Biomass and biofuels offer multi-utilization

Biomass can be defined as biological material that originates from living, or recently living organisms, most often referring to plants or plant-derived materials. Unlike other renewable energy sources, biomass can be directly converted to liquid fuels, the so called biofuels. The two most common types of biofuels are ethanol and biodiesel, whose production is constantly growing in the last two decades.

Ethanol is produced by the fermentation of biomass high in carbohydrates through a process that is quite similar to the one of brewing beer. The practical use of ethanol is as a fuel additive to reduce the total vehicle's greenhouse gas emissions.

Biodiesel, on the other hand, is produced by combining alcohol with vegetable oil or animal fat. Biodiesel is also used as an additive to reduce car greenhouse gas emissions and it can be also used in its pure form as a renewable alternative fuel for diesel engines.

The oil market is more volatile than ever before and because of this biofuels are really among only handful of alternatives to gasoline. The largest ethanol and biodiesel producers in the world are United States and Brazil.

Chinese are also rapidly entering the biofuel market. China has constructed the world's largest fuel ethanol facility at Jilin. This facility uses corn, but Chinese have been already experimenting with cassava, sweet potato and sugar cane.

The increased biofuel production requires adequate support from government. The positive example of the supportive biofuel policy comes from the Germany where Germany government has slashed taxes on biofuel production.

There are many ongoing researches from all over the globe where scientists look for new ways to transform biomass into energy. The key is to find the most cost-effective solution to produce biomass and biofuels, the one that could challenge fossil fuels in terms of efficiency and total costs.

Among most interesting studies is the one coming from the Pennsylvania State University. The researchers at the Pennsylvania State University have developed an electricity generator that is fuelled by human waste. This system is able to produce 51 kilowatts of power from the waste of 100,000 people.

The researches of this kind could be especially helpful to the third world countries that are often lacking funds when discussing new energy options. The notable work in this area is being done at national environmental engineering research institute (NEERI) Nagpur, Maharashtra, India where researchers are developing the use of activated sludge to evaluate its potential as a source of microorganisms capable of producing biodegradable plastics.

The multiple utilization of biomass is one of its main advantages when compared with other renewable energy sources. Just imagine what kind of breakthrough solution for both environment and economy would be if world could transform much of its enormous waste to useful energy. 

Payback period of domestic wind turbine system

Wind energy is often being touted as clean and environmentally friendly form of renewable energy, the one that can help clean our environment and protect us from various environmental issues such as climate change. However, when installing wind turbines people are not only interested in going green but they also want to know more about the total needed investment and how to calculate the payback period for the installation of domestic wind turbine systems.

As the global population continues the demand for energy continues to rise. The main problem with this is, of course, that currently our energy needs are being met through the processing and burning of coal, oil and other fossil fuels. There are two main drawback of our dependence on fossil fuels, for one they are present in limited quantities, and eventually will become exhausted and the second reason is that they are hurting our environment, mostly in form of harmful greenhouse gas emissions that cause climate change and air pollution.

It is no wonder that many countries in the world tend to change their existing infrastructure in order to make the switch to more renewable power in their energy grid.

The first thing when doing the calculation of payback period is to know how much money you are planning to spend on the purchase and installation of your wind turbine system. The best way to achieve lowest installation costs is to look online and contact some local dealers to learn how much it will cost to buy and install a desired wind turbine system at your home.

There are several different factors you should take into account here –these include size, total energy output and construction and transport costs. You can run this analysis on several different wind turbines in order to determine if one is a better deal than the other. Obtaining the information on the cost and the energy production of a wind turbine is a necessary first step in order to calculate the payback period.

In some cases there are available government incentive programs for installation of wind turbines on your property, so it is worthwhile to check with a local dealer to make sure whether you can obtain certain incentives or not. If there are available rebates or tax incentives, then you are able to subtract whatever money you get back from your initial cost expenditures.

The starting expenses needed for the installation of your wind turbine system minus any incentives you might get is your cost for the first year. To calculate saving for the second and next year you need to know the total output of your wind turbine system. To get a plausible estimate, take somewhere around 70% of that number and then multiply your expected energy output by the cost per kWh from your bill. This will show you how much money you can expect to save.

For most people, their initial investment is recouped in between seven and ten years. Since wind turbines have an average lifespan of 20+ years you can save plenty of money on the long run by installing domestic wind turbine system.

Wind energy – worth the effort or not?

Wind energy is one of the fastest growing renewable energy sectors in the world. We are talking about a clean (greenhouse gas emission-free) and renewable source of energy that is receiving plenty of attention worldwide. Today, wind energy is considered as the second fastest growing renewable energy sector, right after solar energy.

With lots of positives that people can achieve from harnessing wind energy, there are millions of homeowners all over the world who choose to install residential wind turbines to supply electricity for their home. However, is wind energy really worth the effort? This can be best answered by looking at the positives and negatives of installing wind turbines.

Wind Energy Positives

1. Wind energy is free and renewable source of energy that is available almost everywhere and you do not have to pay to get wind because nobody owns the wind, and as long as the sun keeps shining, wind will always be there.
2. Installing wind turbines can help you to save money on your electricity bill. Wind turbines can immediately after installation produce electricity for your home (of course, if there is enough available wind energy in your area). By installing wind turbines you can therefore achieve a significant reduction on your electricity bill. In some cases you can even earn some money if your turbines generate more electricity than your household needs by sending the excess back to the grid.
3. Wind turbines do not produce harmful greenhouse gas emissions or any other dangerous pollutants. Unlike fossil fuels and nuclear energy wind energy is clean and has zero emissions.
4. More wind energy helps reduce our carbon footprint – This means that by installing wind turbines we can save thousands of tons of carbon dioxide emission and thus help decrease the ever growing climate change impact.
5. Wind energy is becoming increasingly cost-competitive with fossil fuels - The prices of wind turbines have decreased by more than 50 percent in the last ten years. The constant technological development and high demands are the main factors behind this decline in prices. As the demands for wind turbines keep on increasing, the price of wind energy will continue to further decline in years to come.
6. Many countries have mandatory wind energy targets- Many countries from all over the world have set a goal to supply some percentage of their national electricity needs from wind energy by the year of 2020 or further.
7. Wind energy industry is creating new, well paid jobs – According to some estimates there are one million wind energy jobs in China alone. When turbines are being installed, the installation alone can create hundreds of construction jobs. Once the turbines are installed they usually create tens of operation and maintenance jobs.
8. Overall speaking, wind energy has positive environmental impact, particularly when compared with currently dominant fossil fuels - Many environmentalists still claim that wind turbines are dangerous to wildlife especially birds. However, from thousands of turbines that have been installed all over the world, there is still no concrete proof that would show that wind turbines are presenting the real danger to wildlife and environment.
9. Tax benefits and other favorable incentives are available in many countries of the world. – U.S. and U.K., for instance, are among countries that offer favorable tax incentives for homeowners who install wind turbines.

Wind turbines do not produce harmful greenhouse gas emissions or any other dangerous pollutants (directly).

Wind Energy Negatives

1. Wind energy is not the most reliable source of energy – It is true that wind is available everywhere but it is sadly not available at anytime. Also, the average wind turbine requires at least 10 mph of wind speed to operate normally. What this means is that in areas with low wind speeds we cannot achieve much from this renewable energy in terms of total output and efficiency without the adequate energy storage solution (the intermittency of wind energy).
2. The question of aesthetics - Both commercial and residential wind turbines can slightly reduce aesthetic value of natural landscape, though this question is still a highly debatable one.
3. Wind turbines are sometimes being connected with noise pollution - Wind turbines, especially the large ones, produce noise from blades movement and other moving parts. Some people feel annoyed with the noise levels coming from these turbines. However, the new, recently produced turbines have been designed to work more silently, and as the technology develops further noise pollution issue will likely no longer be connected with wind turbines.
4. The initial investment is still relatively high, even despite the drop in prices – An average residential wind turbine can have costs of up to $5,000. The good side is however that manufacturers offer 20+ years warranty on their wind turbines so $5,000 still looks like a very good deal, particularly on the long run. The additional bonus is that the wind turbines only require low maintenance.

Both commercial and residential wind turbines can slightly reduce aesthetic value of natural landscape.

As concerns about climate change and air quality continue to mount, wind energy can provide residents and businesses with the electricity they need without the harmful emissions associated with conventional electricity generation sources, but wind power is not without controversy.

Huge solar energy improvement - Nano-sized antenna arrays

Solar energy is not only the most popular energy source in the world, it is also the most abundant energy source of them all. Still, solar energy is still far behind fossil fuels in terms of primary energy consumption, mostly because of its lack of cost-effectiveness when compared with traditional energy sources (coal, oil, hydro and natural gas).

One of the latest promising technologies comes from the University of Connecticut engineering professor Brian Willis. The first tests have showed the excellent potential and this technology looks to have what it takes to vastly improve today's solar energy systems.

The basic principles of this technology that rely on incredibly small nano-sized antenna arrays that are in theory capable of capture more than 70 percent of the sun's electromagnetic radiation and simultaneously converting it into usable electric power thus greatly improving the efficiency of currently used solar cells.

With today's technology, even the most effective silicon panels are not able to collect more than 20 percent of available solar radiation, not to mention that the separate mechanisms are needed to convert the stored energy to usable electricity for the commercial power grid. This pretty much efficiency as well as quite an expensive development costs are the two major stumbling blocks to the widespread adoption of solar power as a practical replacement for traditional fossil fuels.

Theoretically promising is not anything for commercial production and scientists have lacked the technology required to construct and test because the fabrication process is extremely challenging. The nano-antennas because of their ability to both absorb and rectify solar energy from alternating current to direct current must be capable to operate at the speed of visible light and be built in such a way that their core pair of electrodes is a mere 1 or 2 nanometers apart, which is approximately 30,000 times smaller than the diameter of human hair.

Illustration of a working nanosized optical rectifying antenna or rectenna (source).

However, the potential solution for fabrication issue can perhaps be found in the selective area atomic layer deposition (ALD) that was developed by Willis. The Professor Willis developed the ALD process while teaching at the University of Delaware, and patented the technique in 2011.

As he explained it is through atomic layer deposition that scientists can finally fabricate a working nano-antenna device. In a nano-antenna, one of the two interior electrodes must have a sharp tip, similar to the point of a triangle. The trick here is getting the tip of that electrode within one or two nanometers of the opposite electrode, which is something similar to holding the point of a needle to the plane of a wall. Before the ALD came into the picture, the existing lithographic fabrication techniques were unable to create such a small space within a working electrical diode. Even when using sophisticated electronic equipment such as electron guns, the closest scientists could get was about 10 times the required separation. However, through ALD, Willis was able to precisely coat the tip of the nano-antenna with layers of individual copper atoms until a gap of about 1.5 nanometers is achieved. The process is self-limiting and stops at 1.5 nanometer separation.

The size of the gap is of vital importance because it creates an ultra-fast tunnel junction between the nano-antenna's two electrodes, which allows a maximum transfer of electricity. This gap also gives energized electrons on the nano-antenna just enough time to tunnel to the opposite electrode before their electrical current reverses and they try to go back. The triangular tip of the nano-antenna prevents electrons to reverse direction, thus capturing the energy and rectifying it to a unidirectional current.

These nano-antennas, because of their incredibly small and fast tunnel diodes, are capable of converting solar radiation in the infrared region through the extremely fast and short wavelengths of visible light, something that has never been accomplished before. The current solar panels build on silicon have a single band gap which, allows the panel to convert electromagnetic radiation efficiently at only one small portion of the solar spectrum unlike nano-antennas that are able to harvest light over the whole solar spectrum, creating maximum efficiency.

Prior to the advent of selective atomic layer deposition (ALD), it has not been possible to fabricate practical and reproducible nano-antenna arrays that can harness solar energy from the infrared through the visible and ALD is what makes the creation of these devices possible. The atomic layer deposition process is favored by science and industry because it is simple, easily reproducible, and scalable for mass production. The method being used to fabricate nano-antennas can also be used in thermoelectrics, infrared sensing and imaging, and chemical sensors.

Willis has already made the prototype device and as he says „now we're looking for ways to modify the nano-antenna so it tunes into frequencies better.“ The question whether these devices really function at this high level of efficiency is yet to be answered?’ Theoretically this is possible, but further tests in practice will tell us the rest of the story.

PV electricity generation is not that complicated

The process of generating electricity with a photovoltaic solar system is not as complicated as many people think it is. It's actually a rather simple process that consists of several different principles. The basic principle is at follows; once the sunlight hits the surface of the PV panels the electrons in the solar cells get activated. The activation of electrons means that they start to move with much bigger frequency, and in the process they start to bump into each other more frequently. This interaction between the electrons is what generates electricity.

A solar (photovoltaic) panel or module consists of large amount of individual solar cells. If we were to simplify things we could say that solar cell is primarily silicon with some circuitry. The more cells there are in a solar panel, the more electricity it can generate. A string of panels makes up an array and multiple arrays comprise a solar PV system.

If we were to divide things even further we could say that PV system is only one form of harnessing solar energy. For instance, hot-water system is used specifically to heat water while A Concentrated Solar Power system (CSP) uses mirrors to focus sunlight on water, causing it to boil producing steam, which is then used to generate electricity.

PV systems are in most cases connected to the grid with the only real exception here being people in more remote locations where a battery back-up system is often lot more practical. Two primary types of solar panels are mono-crystalline and polycrystalline.

Silicon is the primary material used in solar panels as the main active material in a solar cell, primarily because of its unique chemical properties. A silicon atom is comprised of twelve electrons on three separate 'shells' or layers. The outermost 'shell' has four electrons that are highly reactive. The outer electron shell of a silicon atom is seeking to reach of state of equilibrium by 'sharing' its electrons with other atoms. Conversely, those other atoms will share their electrons as well.

These electrons are always moving but the energy from the sun causes their rate of movement and interaction to increase. By bumping into each other more frequently they generate friction and this is what generates electrical energy. After this phase it is only a matter of channeling the current through all the wiring to the inverter. The inverter is needed to convert the electricity from direct current to alternating current because our electrical grid is not designed to handle direct current. In a grid tied system any excess current is supplied back to the grid. In off-grid PV system there is usually a battery back-up system to store excess current generated by the system for later use.

Generating electricity from the sun is a very practical way to meet our electrical demand, especially because solar panel prices have decreased by more than 70% in the last five years. This particularly applies to remote and isolated areas where using PV panels to generate electricity is far more efficient than rebuilding entire energy grid.

Latest research on environmental impact of wind turbines

Offshore wind farms and noise pollution issue

Although majority wind turbines are built on land there are also many suitable offshore locations where offshore wind turbines can be built. Offshore wind energy projects have lately become very popular in some countries of the world, most notably United Kingdom and offshore wind energy is set to play major role in global clean energy market in years to come. Offshore wind energy projects can provide better efficiency compared to the wind energy projects on land because of powerful winds that are also more stable and frequent as compared to those that blow on land. The major drawback is however construction costs, being significantly higher for offshore wind energy projects since they need to be constructed to withstand extreme weather conditions.

Growth in offshore wind generation is expected to play a major role in fight against climate change issue by meeting carbon reduction targets around the world, however the environmental impact that offshore wind turbines have on marine life hasn't been much researched as is also the case with the impact of construction noise on marine species. There could available be a lot more information about this matter because the scientists from the United Kingdom and the United States have recently managed to develop a method to assess the potential impacts of offshore wind farm construction on marine mammal populations, with the special emphasis on the noise made while driving piles into the seabed which occurs while installing wind turbine foundations.

The researchers report that pile driving during the construction of offshore wind farms produces a staggering amount of noise which is potentially harmful to marine species. This is particularly hazardous for already endangered marine species, such as protected populations of seals, dolphins and whales.

The researchers studied ongoing construction in and around the North Sea, where many proposed wind farm sites are on submerged offshore sandbanks. These sandbanks provide important habitats for many different marine mammals and seabirds. Several previous researches focused their attention on the potential impacts to birds, while this latest comprehensive research tries to assess the potential long-term impact of construction on protected marine mammal populations, particularly harbor seals. In United States where offshore wind power development is set to grow rapidly in years to come, this type of assessment could be applied to wind turbine construction that may impact a number of endangered species, including three whale species: the North Atlantic right whale, the humpback whale, and fin whale.

This study aims to present takes a worst case assessment of the short term impacts of noise pollution coming from installation of offshore wind turbines and how these negative effects of excessive noise may influence longer term population change. The information gathered from this study should provide information that would allow regulators to balance their efforts to meet both climate change targets and existing environmental legislation thus paving the way for sustainable offshore wind energy development.

It has been reported that harbor seals can be impacted by the noise pollution in several different ways. Particularly damaging loud construction activities can cause traumatic hearing injury or even death at the close range while little bit less loud noise pollution levels could lead seals to avoid the area and lose favorite feeding grounds, potentially causing greater competition in other areas thus leading to problems with finding food which could negatively result in lower reproduction or survival rates. Also, the changes in hearing sensitivity could make seals more vulnerable to predation, thus further reducing their numbers and putting their future survival in question.

Bat deaths from wind turbines – Exaggeration or not?

Several different studies were studying the impact that wind turbines have on bat population. There hasn't been a general opinion on this matter with some studies reporting minimal bat dearth rates while other reporting alarming bat death rates.

A brand new estimate of bat deaths caused by wind turbines concludes that more than 600,000 of bats have probably died in 2012 in the United States. This latest estimate is published in an article in Bioscience and has caused plenty of controversies. The researchers   used sophisticated statistical techniques to predict the probable number of bat deaths at wind energy facilities from the number of dead bats found at 21 locations, correcting the statistics for the installed power capacity of the facilities.

Many people care very little about bats, but nonetheless they play an important role in the ecosystem because of their role as insect-eaters, not to mention that they also pollinate some plants.

How are bats killed by wind turbines? It is not only by collisions with moving turbine blades, but in some cases also by the trauma resulting from sudden changes in air pressure that occur near a fast-moving blade, particularly in large wind turbines.

Mark Hayes of the University of Colorado says that 600,000, although a big number is still a conservative estimate with the possible actual figure 50 percent higher. The data that Hayes analyzed also leads to conclusion that some areas of the United States might experience much higher bat fatality rates at wind energy facilities than others and it has been reported that the Appalachian Mountains have the highest estimated fatality rates in entire United States.

The consequences of deaths at wind farms for bat populations are hard to assess ad give exact numbers primarily because there are no high quality estimates of the population sizes of most North American bat species. Wind farms are just another negative factor in the line for bat populations because these mammals are already under stress because of climate change and disease, in particular white-nose syndrome.

Conclusion

One can not say that using wind energy is perfect from environmental point of view because every source of energy, renewable or not, has some negative environmental effects. In any case, using wind energy is definitely better for environment than staying with fossil fuels. Of course, future technological development must go hand in hand with the protection of species such as whales and bats, and thus we need to make future wind farms, offshore and onshore, as environmentally friendly as possible because this is the only way to ensure sustainable wind energy development.

The overall effect of wind turbines still remains more positive than negative, particularly in comparison to environmental damage done by currently dominant fossil fuels (climate change, different forms of pollution). There is still plenty of room to improvement and wind project developers need to apply different technological innovations in order to minimize the damage done by installation and operation of large wind turbines. Hopefully, future research will provide new environmentally friendly technological solutions for wind turbines. Some positive examples already exist such as for instance equipping turbines with radars to protect birds from colliding with its blades.

Wind energy development, effects and outlook

Wind energy industry is together with solar energy the fastest developing renewable energy sector with the fairly competitive prices in comparison to currently dominant fossil fuels but this doesn't mean that wind energy can be regarded as the perfect energy source because there are several things wind energy industry will need to improve in years to come in order to become one of the dominant energy source.

To start with, wind energy industry despite being one of the most cost-competitive energy sources is still unable to maintain its current tremendous growth without the adequate incentives and favorable policies, the proof of which is clearly seen from the current situation in United States (wind energy tax credit and the controversies about its prolongation). What this means is that wind turbines will have to significantly drop in prices and will also have to become more effective. Achieving both cost-competitiveness and satisfying efficiency can only be achieved with the help of science. In this sense, the global wind energy industry requires the continuation of technological development as one of the key components that will determine the future of wind power industry.

The benefits of using wind energy

Wind energy is together with solar energy the most popular and most talked about renewable energy source. It is also one of the fastest growing renewable energy industries in the world. There are many benefits of using wind energy and by this I do not mean only environmental benefits.

Using wind energy has many environmental benefits. If world would to make a switch from fossil fuels to wind energy then this would first of all mean fewer greenhouse gas emissions (greenhouse gas emissions contribute to global warming and climate change). Wind energy also doesn't contribute to air and water pollution and has overall very low environmental impact.

Since wind power is a renewable source of energy it cannot be depleted. Wind energy can therefore provide future energy security once fossil fuels become exhausted.

Wind energy has excellent global potential. The global wind energy potential is more than five times more than the world's current energy demand.

More wind energy (instead of sticking with fossil fuels) also means reduced need for foreign fuel import. By developing domestic wind energy sector instead of relying on expensive foreign oil we can give big boost to our economy in form of new jobs, and most of all our money stays inside our borders.

Wind energy can be developed on land as well as offshore, meaning that each country can choose wind energy option that best suits its needs.

Wind power is currently the most cost-competitive renewable energy source. In some areas of the world wind power has already achieved cost-parity with fossil fuels. Wind turbines are also becoming bigger, more efficient and more technologically sophisticated.

The global wind power capacity continues to grow rapidly. There's no doubt whatsoever that wind energy will be a key part of our clean energy future.

Wake turbulence behind individual wind turbines can be seen in the fog in this aerial photo of the Horns Rev wind farm off the Western coast of Denmark.

Environmental effects of wind energy – Not everything is positive

The positive environmental effects of wind energy were already briefly mentioned above, and now we'll say a bit more about this interesting topic.

Using wind energy is lot more environmentally friendly that continuing our dependence on fossil fuels such as coal and oil. This however doesn't mean that using wind turbines is always positive for environment and through this article I will mention certain environmental issues connected with harnessing wind energy and using wind turbines.

Wind energy opponents usually start pouring critics about wind turbines with noise by saying that large wind turbines create excessive noise pollution levels which hurt nearby environment. This is somewhat true because large wind turbines with gigantic blades can produce excessive noise levels and despite the technological advancement over the recent years the noise levels connected with large wind turbines pretty much remained the same. The noise pollution therefore remains the biggest environmental issue connected with wind turbines.

Large wind turbines can also hurt wildlife because birds can be caught by their blades. Birds are not the only animals that can be jeopardized by large wind turbines. The animals that live underground can also be jeopardized because large wind turbines require very deep foundations meaning that their habitats might be destroyed in the process.

Wind energy opponents also complain about the visual look of turbines by claiming that they interfere with the aesthetics of perfect natural landscape as they do not fit in the visual appearance of certain area thus degrading the natural beauty of given environment. This is a highly controversial question because aesthetics is really a matter of personal opinion, so I'll not debate about this issue any longer as this is really more about individual opinion so it is difficult to draw general conclusion about it.

As can be clearly seen from above paragraphs wind energy isn't 100% environmentally friendly source of energy and using wind turbines can also lead to negative environmental impact but this harmful effect is definitely not the reason to move away from wind power and continue our dependence on fossil fuels. The currently dominant fossil fuels such as coal and oil create much bigger environmental damage in form of climate change and air pollution so the environmental damage coming from wind turbines is really negligible compared to environmental damage coming from fossil fuel fired power plants.

This means that replacing fossil fuels with wind energy is much more positive to our environment in comparison to staying with fossil fuels. Of course, the role of the science is vital as it should find new solutions to make wind turbines more environmentally friendly by reducing their noise output as well as equipping them with suitable equipment (such as radars) in order to prevent large bird killings.

Conclusion and future outlook

According to the latest study by Pike Research global wind energy market looks set for the steady growth in the next few years. Pike Research’s report, Global Wind Energy Outlook predicts that by 2017 wind power installations will represent $153 billion global industry.

The numbers in this study predict that in a period 2011-2017 global investment in new wind power capacity will reach $820 billion, and total wind power capacity will grow from current 235.8 GW to 562.9 GW in 2017.

Wind turbines are not only becoming cheaper but are also growing in size which until now weren't considered to be either practical or economical. Wind power is already the low-cost option in many regions, especially in the ones with scarce fossil fuel resources.

Wind power industry will likely continue its growth in years to come, and if everything goes as expected wind power should satisfy more than 20% of world's electricity by the end of this century. There are still some issues like efficiency and intermittency which wind power industry will have to resolve in years to come but nonetheless wind power industry should already look forward to a very bright future.

Solar energy potential, current issues and future role

Solar energy is form of renewable energy that receives the lion share of media coverage. There are several reasons for this with most obvious being that Sun is free and practically unlimited source of energy, for at least next five billion years. Solar technologies are constantly developing and are vastly improving its cost-effectiveness ratio as compared to other energy sources though it also has to be said that solar energy is still some way off from achieving cost parity with traditional sources of energy (fossil fuels). Solar energy technologies are usually divided on active and passive solar energy technologies. Active solar energy technologies include photovoltaics and solar thermal collectors to harness the energy from the Sun while passive solar technologies include methods such as orienting a building towards the Sun or selecting materials with favorable light dispersing properties.

Many energy experts agree that clean solar energy offers our civilization huge long-term benefits. These not only include positive impact on climate change and less pollution but also limitless source of free energy that is the most abundant of all other energy sources on our planet. Fossil fuels, as many of you already know, are finite energy sources, meaning they will eventually become exhausted, and once this starts to make toll world needs to have adequate alternatives ready, so why not give solar energy a change it most definitely deserves?

What exactly is energy from the Sun?

Sun radiates enormous amounts of energy. It has been said that our planet receives 174 petawatts (PW) of incoming solar radiation at the upper atmosphere, with 70% of this gigantic amount being absorbed by clouds, oceans and land masses. It has been estimated that the total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. Energy from the Sun is essential for all life on our planet, and our planet is heavily dependent on this energy. Without solar energy there also wouldn't be photosynthesis, a base for the entire food chain on our planet. Harnessing solar energy to power our entire industry and society in general is currently a dream but in years to come this dream could well become a reality, after all this is pretty logical conclusion when you consider the total amount of available solar energy and the miniscule amount of this total number we need to power our world.

Sun radiates enormous amounts of energy.

Solar energy development – The challenges that need to be overcome

Solar energy industry is still fairly young in terms of development, and therefore still lacks the "proven technology" mark that other energy sources, most notable fossil fuels, have. The lack of maturity of solar energy sector means that efficiency is still inadequate and that the total costs are still too high, meaning that solar energy industry still has a mountain to climb in order to become cost-competitive with fossil fuels.

The prices of solar energy technologies are still relatively high but the good news is that they are also constantly declining though still not enough to compete with the costs of fossil fuels without the subsidies. High costs, lack of maturity in development, and the lack of tradition are top reasons why solar energy is still couple of decades away before achieving cost-parity with fossil fuels. Solar energy storage issue is also one of the challenges for young solar energy industry. Sun doesn't shine at night or when it is cloudy or raining so what the industry needs is an adequate solar energy storage technique that would do the job in these situations by providing reliable supply. The scientists from all over the world are currently working on solar energy storage issue and the world still eagerly awaits effective solution to this issue.

What exactly are photovoltaics?

Photovoltaic is term with which we are often bombarded with by solar energy industry. The best way to define photovoltaics would be to say that these are devices that convert sunlight into electricity by using the photoelectric effect. Solar cells are also often referred to as photovoltaic cells, and they aren't exactly the brand new technology as some people think they are. The creation of first photovoltaic cell is more than one century old as the first one was constructed by Charles Fritts in the 1880s. It also has to be said that the first significant application where solar cells showed their potential and worth was as a back-up power source to the Vanguard I satellite in 1958.

Photovoltaic cells are made of semi-conducting materials very similar to those used in computer chips. There are several different types of photovoltaic cells and it is still early to tell which one will win the commerciality race; among those that are currently mostly used are thin film, monocrystalline silicon, polycrystalline silicon, and amorphous cells.

Concentrating photovoltaics is also well known term used by global solar energy industry. Photovoltaic cells that are designed to operate with concentrated sunlight are built into concentrating collectors that use lenses to focus the sunlight onto the cells. It is fair to say that this may not be an ideal solution because the lenses must be pointed at the sun so the efficient use of concentrating collectors is really limited to location with the highest solar insolation values. However, concentrating photovoltaics are advantageous in terms of costs because they use very little expensive semi-conducting materials.

An average photovoltaic cell has an efficiency of 15%, which means that less than one-sixth of the sunlight striking the cell actually generates electricity which means that efficiency levels are in need of massive improvement in order for photovoltaics to rule the global energy market and achieve cost-parity with fossil fuels.

Current usage and conclusion

Solar energy can provide us with over 1000 times more energy than this world currently needs but despite of this enormous potential solar power is yet to reach tiny 0.03% of the world's total energy supply.

There are several answers to the question why the world isn't using more solar energy to satisfy its huge energy demand. As already said above solar energy technologies are still in the very early phase of development, which gives us an answer as to why solar power still fails to achieve efficiency comparable with fossil fuels. An average solar panel has an efficiency of around 15 percent, which means that large amount of solar energy gets wasted, and ends up like a heat instead being turned into some form of useful energy. The intermittency is also one of the burning issues that solar energy sector will have to find the solution for in the form of adequate solar energy storage method. In fact, making solar energy panels lot more effective and far cheaper is what global solar energy industry needs to dominate. The science will have to play its part, and so will the politics because without politics science cannot obtain the necessary funds needed for further research and important new discoveries. Luckily, many of the world countries favor solar energy and the sector has become well subsidized in the recent years which resulted in many favorable policies for future solar energy development in much of the world. It 's no doubt that solar energy industry will continue to develop and further improve, and if all goes according to the plan, in one moment of the time, solar energy will become the dominant form of energy on our planet. It's difficult to predict when exactly will this moment come, but there are very few of those who doubt future leading role on solar energy industry on global energy market.

Quick guide to geothermal energy extraction

Geothermal energy is abundant renewable energy resource that is yet to fulfill its immense potential because geothermal energy is currently being harnessed in only 24 countries of the world, with U.S. still being the world’s largest geothermal producer. Harnessing geothermal energy refers to extracting heat below the Earth's surface for electricity generation and for heating/cooling purposes.

Geothermal energy is basically a heat within the Earth's core. This heat remains at a relatively constant temperature throughout the entire year, meaning that geothermal energy does not suffer from intermittency issue like this is the case with solar and wind energy, and is available 24-7 without the need for some backup energy storage solution. This naturally available energy is extracted by a series of pipes filled with water buried below the Earths surface. This hot water is then used in our homes for heating purposes or to generate electricity.

Geothermal Power Plant - Hot water is pumped from deep underground, turned to steam to power turbines and generate electricity, cooled back to water and then pumped back into the Earth.

What is the main working principle of geothermal energy? Within the Earth's core, somewhere around 4000 miles below the surface, temperatures can reach over 9000 degrees Fahrenheit. This enormous amount of heat originated four billion years ago in a fiery combustion of dust and gas in time when our planet was created. It is the radioactive decay of the inner core that keeps the heat generating and flowing outward from this inner core to the mantle of harder rock which surrounds the core. Once the temperature and pressure reach high enough levels, some of this mantle rock melts. Then, because the melted rock or magma has lesser density when compared to surrounding rock, it rises and moves slowly up to the Earth's crust.

In rare occasions the hot magma moves all the way to the Earth's surface in a form of a volcanic eruption, but in most cases the magma remains underground and heats the adjoining rock as well as any water that has seeped down through holes and cracks. Some of this water, whose temperatures can reach as high as 700 degrees, travels back up through cracks to the Earth's surface and emerges in forms of hot springs and geysers. In most cases, however, the water and magma are trapped within the rock, forming a natural underground geothermal reservoir. It is these underground geothermal reservoirs that are the enabling us the extraction of geothermal energy for the purposes of heating and generating electricity.

Geothermal Heat Pump - In winter cold air or water is pumped trough underground pipes to heat, and in the summer hot air or water is pumped trough underground pipes to cool. 

In order to use geothermal energy for heating/cooling purposes one needs to install geothermal heat pumps. Geothermal heat pumps are significantly more efficient compared to conventional heating and cooling systems and their main advantage is the fact that they can move heat in two ways: during the hotter summer months, the geothermal heat pump operates by removing the heat from the building and dissipating it back into the ground, while in the cold winter months heat gets withdrawn from the ground (the heat source) and is used to heat building.

The process of using geothermal energy for electricity generation is as follows: extremely hot water from the underground is pumped to surface and once it reaches surface it turns to steam where it is used to power turbines that generate electricity.

Biofuels cannot help decrease greenhouse gas emissions?

Biofuels are touted by many energy experts as one of the energy options that can lead to less greenhouse gas emissions in years to come. But not everyone is thrilled with the thought of increased biofuel production. One of the latest researches coming from Italian scientist Simone Vieri of the University of Rome argues very interestingly that biofuels will primarily serve the interests of large industrial groups rather than helping to decrease greenhouse gas emissions and ward off climate change.

When describing policies to combat climate change, Vieri points out that the European Union has planned to increase to 10% the share of fuel derived from biofuels on the market by 2020. The problems is that EU focused attention mainly on first-generation biofuels, made from the conversion of plant material which can be grown specifically for fuel production, such as corn, soy, sugarcane or palm oil. The second-generation biofuels, made from agricultural and woody crop biomass, including waste and by-products, is still in second plan and is not expected to play major role in achieving this goal.

By further analyzing currently available data and predicting future trend Vieri highlighted that in 2020 European Union will not be able to keep to its 10% biofuels goal focusing only at European agricultural production, but will have to continue importing the greatest part of raw materials, or biofuels from abroad.

The primary focus on first generation biofuels favors „production systems that are in competition with traditional agriculture for use of resources and production factors“. It can also lead to exploitation of human and environmental resources of poorer countries. The most important conclusion however is that the agricultural production processes that change land use can lead to zero net benefit in terms of emissions reduction.

If we look at the things from market perspective there are also several important observations. For example, financial market speculation strengthens the link between the price of oil and the price of the main agricultural raw materials, and increase in agricultural product prices also can lead to devastating impact on poorer nations and their food security.

Vieri further concluded that „the choice to promote first generation biofuels is an example of how politics places the protection of the interests and profit strategies of a restricted number of subjects before the costs and benefits to be had on a wider scale“.

Failure to achieve sustainable biofuel production would only raise the profits of multinationals and count for nothing in terms of reducing the global carbon footprint. Finding the right „green economy“model can only be achieved with the sustainable biofuel production, and focusing on first generation biofuels doesn't look to be the good solution.

Hydrogen production cost-effective soon

Hydrogen is the most abundant element in entire Universe so it comes to very little surprise that scientists are working on different ways to cost-effectively produce hydrogen. One of the recently talked about solutions for hydrogen production, as a potential source of almost unlimited energy for fuel cells, is silicon. The US scientists at the University of Buffalo have recently discovered that super-small particles of silicon react with water to produce hydrogen almost instantaneously.

This was confirmed by the series of numerous experiments in which the scientists created spherical silicon particles about 10 nanometers in diameter. When combined with water, these particles reacted to form silicic acid and hydrogen. The benefits of these experiments include the facts that the reaction didn't require any light, heat or electricity, and the production rate was excellent as it enabled production of hydrogen about 150 times faster than similar reactions using silicon particles 100 nanometers wide, and 1,000 times faster than bulk silicon, according to the study.

The produced hydrogen was defined as relatively pure by testing it successfully in a small fuel cell that powered a fan. What this means is that in processes that include splitting water to produce hydrogen, nano-sized silicon looks like a lot better solution than the more obvious choices aluminum that people have studied for a while. The researchers hope that with the further development, this technology could form the basis of a 'just add water' approach to generating hydrogen on demand and have also revealed that the most practical application for this process would be for various portable energy sources.

Particularly surprising was the speed at which the 10-nanometer particles reacted with water. In under a minute, these particles produced more hydrogen than the 100-nanometer particles produced in about 45 minutes. The maximum reaction rate for the 10-nanometer particles was about 150 times as fast.

The reason of this discrepancy is said to be geometry because larger particles form non-spherical structures whose surfaces react with water less readily and less uniformly than the surfaces of the smaller, spherical particles. The downside is that it still takes significant energy and resources to produce these super-small silicon balls, but nonetheless these particles could help power portable devices in situations where water is readily available and portability is more important than low cost (such as military operations).

Hydrogen can be rapidly produced from silicon, one of Earth's most abundant elements, and this paves to way for future discovery which could one day turn hydrogen into one of the most important energy sources in the world.

The things were taken even further when Stanford University scientists recently created a silicon-based water splitter that is both low-cost and corrosion-free. This new splitter, which is basically a silicon semiconductor coated in an ultra thin layer of nickel -- could help pave the way for large-scale production of clean hydrogen fuel from sunlight, according to the Stanford scientists.

As researchers reported solar cells only work when the sun is shining meaning that when there is no sunlight, power needs to be generated from conventional power plants that run on fossil fuels such as coal or natural gas. The greener solution to this dependence on coal and natural gas fired plants would be to supplement the solar cells with hydrogen-powered fuel cells that generate electricity at night or in times when demand is especially high.

The first thing that needs to be enabled prior to using this greener solution is to produce clean hydrogen. The novel hydrogen research uses technology called water splitting. The working principle of this technology is as follows: Two semi-conducting electrodes are connected and placed in water where they absorb light and use the energy to split the water into its basic components, oxygen and hydrogen. At the end, the oxygen is released into the atmosphere, while the hydrogen is stored as fuel. When energy is needed, the process is reversed as stored hydrogen and atmospheric oxygen are combined in a fuel cell to generate electricity and pure water.

The entire process is sustainable and environmentally friendly because it emits no greenhouse gases. But finding a cost-effective way to split water still looks to remain a major challenge and researchers continue searching for inexpensive materials that can be used to build water splitters efficient enough to be of practical use for hydrogen production.

Some researchers have turned to xylose as the solution for hydrogen production. One of the most notable researches on hydrogen production comes from the Virginia Tech where scientists have discovered a way to extract large quantities of hydrogen from basically any plant. This discovery has the potential to revolutionize the entire hydrogen fuel production because of its high potential to bring cost competitive and environmentally friendly hydrogen fuel as a viable alternative to our current dependence on fossil fuels such as coal and natural gas.

The major accomplishment that researchers have achieved was that they used xylose, the most abundant simple plant sugar, to produce a large quantity of hydrogen. Prior to this study this process was pretty much attainable only in theory, and had no practical proof.

The main benefits of this brand new hydrogen fuel production process include focus on renewable natural resources, negligible greenhouse gas emissions, and no need for costly or heavy metals. The majority of previously used methods led to significant greenhouse gas emissions, and were connected with high cost and low efficiency.

This process is yet to become commercially available, but has the possibility of making an enormous impact, from both environmental as well as economic point of view. The lead author Y.H. Percival Zhang said that "hydrogen market capacity would soon be at least $1 trillion in the United States alone."

Zhang's team were able to liberate high-purity hydrogen under mild reaction conditions at 122 degree Fahrenheit and normal atmospheric pressure by separating a number of enzymes from their native microorganisms to create a customized enzyme cocktail that does not occur in nature. These enzymes, when combined with xylose and a polyphosphate, were able to liberate the unprecedentedly high volume of hydrogen from xylose, resulting in the production of about three times as much hydrogen as compared to other hydrogen-producing microorganisms.

Hydrogen is definitely one of the most acceptable alternative fuels from the environmental point of view. When hydrogen burns in air, it produces nothing but water vapor, meaning it is totally ecologically acceptable. With little luck and more research hydrogen could even become the most important energy source in the world. The potential is already there, and it is up to science to create solutions to cost-effective harness this enormous energy potential that hydrogen has.

Hydrothermal liquefaction facts

Hydrothermal liquefaction refers to a process that can convert all kinds of biomasses to crude bio-oil. This crude bio oil is much similar to fossil crude oil, up to a point that a simple thermal upgrade and existing refinery technology can be employed to subsequently obtain all the liquid fuels we know and use today.

Hydrothermal liquefaction is connected with very high efficiency levels. It consumes approximately 10-15 percent of the energy in the feed-stock biomass, resulting in an energy efficiency of 85-90 percent.

The big advantage of hydrothermal liquefaction is that it accepts all biomasses from sewage, manure, wood, compost and plant material along with waste from households, meat factories, dairy production and all other similar industries.

This process is said to be the most feed-stock flexible of any liquid fuel producing process (it only consumes approximately 10-15% of the energy in the feed-stock biomass), the one connected with significantly smaller costs as compared to pyrolysis, bio-ethanol, gasification with Fischer-Tropsch.

The brand new HTL method is based on flow production, where the biomass is injected into a 400 °C pre-heated reactor, then cooked under high pressure for  around 15 minutes and afterwards quickly cooled down to 70°C. The temperature of 400°C and high pressure creates so called super critical state, neither liquid nor gas, at which it easily decomposes the biomass.

HTL method is environmentally friendly, since no harmful solvents are involved (crude HTL oil has very low oxygen, sulfur and water content), and looks to be cost-effective since the energy efficiency is very high.

The water that emanates from the HTL process has low carbon contents and can either be recycled into the process or ultimately be purified to attain drinking water quality, which is the scientific long-term goal.

The crude bio-oil coming from HTL process is storage stable, and has comparatively low upgrading requirements, due in part to a high fraction of middle distillates in the crude oil. It can be used as produced in heavy engines or it can be hydrogenated or thermally upgraded to obtain diesel, gasoline or jet-fuels by the existing refinery technologies.

It is often said that bio-oil coming from HTL process is unique because it is directly comparable to fossil crude oil as it can directly enter the existing fuel distribution network for automotive transportation in any concentration.

HTL process isn't „upgrading intensive# as this is the case with some other similar processes such as pyrolysis which needs immediate upgrading in order not to deteriorate.

Crude HTL oil is said to have high heating values of approximately 35-39 MJ/kg.

The most notable hydrothermal liquefaction comes from the Denmark, with Aarhus and Aalborg University leading the way on HTL research at all levels.

Thinner solar cells could be the next big thing

Most technological innovations aimed at improving solar cells have focused primarily on increasing the efficiency of their energy conversion, or on lowering the cost of manufacturing. However, there is another approach coming from MIT researchers that are aiming to produce the thinnest and most lightweight solar panels possible.

These extra thin solar panels have the potential to surpass any substance other than reactor-grade uranium in terms of energy produced per pound of material. The MIT researchers also stated that they could be made from stacked sheets of one-molecule-thick materials such as graphene.

Using two layers of one-molecule-thick materials it is possible to create solar cells with 1 to 2 percent efficiency in converting sunlight to electricity, That's pretty low compared to the 15 to 20 percent efficiency of standard silicon solar cells but the plus side is that is being achieved using material that is thousands of times thinner and lighter than tissue paper. The two-layer solar cell is only 1 nano-meter thick, while on the other hand conventional silicon solar cells are usually hundreds of thousands of times that. The stacking of several of these two-dimensional layers could boost the efficiency significantly thus being able to compete with conventional technologies.

There are certain applications where weight is a crucial factor –this include spacecraft, aviation or for use in remote areas of the developing world where transportation costs are significant, and in these cases using these lightweight cells could be far more beneficial than sticking with conventional technology.

If we were to measure things pound for pound these new solar cells would produce up to 1,000 times more power than conventional photovoltaics. Being so thin makes it advantageous in shipping, but it also makes ease of mounting solar panels and when you consider that half of the costs of today's solar panels are in support structures, installation, wiring and control systems, going for these cells could significantly reduce the total costs.

The fact that cannot be ignored either is that the material itself is much less expensive than the highly purified silicon used for standard solar cells and since the sheets are extra thin, they require only minuscule amounts of the raw materials.

The additional advantage of these materials is their long-term stability, even in open air, while other solar-cell materials must often be protected under heavy and expensive layers of glass. These materials have proven to be quite durable as they are stable in air, under ultraviolet light, and even in moisture.

The researchers are yet to turn computer models into actual production but the potential is certainly there. Perhaps this is the first step to a new trend in solar energy industry, creation of extra thin solar cells.

Is wind really the new oil in Texas?

Texas was for many years been primarily characterized with oil production but today things look mighty different compared to what they looked like a few decades ago. Wind power is becoming increasingly popular energy option in Texas, with state's wind power capacity increasing all the time. The state of Texas has really set the national standards for harnessing wind energy by generating around 10400 MW of wind electricity in 2011, which is almost three times more compared to second-ranked Iowa that generates around 4300 MW.

Such huge emphasis on wind energy is not all about environmental benefits, and although wind energy is one of the environmentally most friendliest energy sources there is much more to wind energy than "just" being ecologically acceptable. Wind energy also provides significant economic benefits by providing new jobs as well as other sources of income.

Term "other sources of income" primarily refers to the large number of Texas farmers that lease their farms so the wind power can be generated. The prices are not bad either as farmer can receive up to $60 per acre to generate wind power. The additional benefit in this whole story is that the land is still adequate for producing food.

Texas certainly doesn't plan to stop its tremendous growth in installed wind power capacity because Texas has so far used only small part of its huge wind energy potential. In fact, according to the latest report from The Electric Reliability Council of Texas (ERCOT) currently installed wind capacity in Texas counts less than 9% of nameplate capacity so there's plenty of room for further growth.

The bigger wind power capacity means more well paid green jobs, in fact the latest estimates show that every new megawatt of installed wind capacity creates around 5 new green jobs, both direct (manufacturing, construction, operations) and indirect (advertising, office support, etc.).

Of course, this doesn't mean that there aren't some problems on the way, and currently the biggest problem with wind power in Texas is not enough transmission lines. But Texas is already solving this problem by establishing the $5 billion project to ensure the transmission of electricity generated by West Texas wind farms to customers in the large cities.

There are currently around 40 wind farms in Texas, with the largest being Roscoe Wind Farm. Roscoe Wind Farm with the capacity of 781 MW is not only the largest wind farm in Texas, but also nationwide. Other large wind farms in Texas include: Horse Hollow Wind Energy Center, Sherbino Wind Farm and Capricorn Ridge Wind Farm. The state even plans its first offshore wind energy project, a 300 MW offshore wind farm in Galveston.

If wind energy sector continues this impressive growth in years to come then wind could soon become more important than oil in the state of Texas. The growing wind power market should help Texas meet its 2015 renewable energy target of 5,000 new megawatts of power coming from renewable energy sources.

Top five renewable energy sources

Renewable energy has started making headlines with many energy experts looking at various renewable energy sources such as solar energy, wind energy, geothermal energy, hydro power, and biomass. Renewable energy is very important because it offers alternative to using fossil fuels, not just in terms of reducing harmful greenhouse gas emissions but also to replace depleting oil, coal and natural gas. Renewable energy also improves our energy security and our energy independence, and is extremely abundant, practically limitless, meaning that the future will no doubt belong to renewable energy.

SOLAR ENERGY

Solar energy is the most abundant energy source on our planet but the world currently uses a tiny fraction of the totally available solar energy. Solar energy technologies are still connected with high costs, and do not offer satisfactory efficiency, though things are certainly improving very fast.

Solar energy is environmentally friendly renewable source of energy. Harnessing solar energy doesn't result in increase of harmful CO₂ emissions. The other advantage of solar energy is that the Sun is virtually unlimited source of energy that could supply with ease our current as well as the future energy demand, even with the predicted global population growth, as for instance covering just 4% of the world's desert area with solar panels would be enough to supply all of the world's electricity.

The downside of solar energy is that solar panels are still connected with relatively high costs, there are many ongoing solar researchers and hopefully science will soon find solutions to improve economics and efficiency of solar power technologies.

In 2012, solar energy accounted for less than 0.03% of the world's total energy supply, which is way too little, given its enormous potential. Despite this small number solar energy sector is constantly growing, and solar energy industry is one of the fastest growing industries in the world. The largest photovoltaic market in the world is still Germany.

Generally speaking, solar power plants have positive environmental impact. Harnessing solar energy doesn't contribute to climate change, acid rains or any form of pollution. This however doesn't mean there are no downsides to solar power plants, for instance manufacturing solar panels involves some toxic materials and the fact that huge solar power require lot of land for construction, and lot of water for cooling purposes.

Solar power plant.

WIND ENERGY

Wind energy has very long tradition as people were using wind energy for more than 5000 years to propel sailboats and sailing ships. These days wind energy is mostly used to generate electricity by using wind turbines. Wind power is one of the fastest growing renewable energy markets, even despite the stagnation in recent years, after losing its popularity to solar energy. Wind farms are no longer being built only on land but also offshore and offshore wind energy could in years to come become dominant way of harnessing wind energy.

Wind energy is ecologically acceptable renewable energy source that does not contribute to climate change or air pollution. Wind turbine prices are constantly decreasing and wind is certainly becoming cost-competitive on global energy market, as it currently represents one of the few renewable energy sources that could actually compete with fossil fuels in terms of economics.

Wind energy is intermittent energy source, and in times when wind doesn't blow we need another backup energy option to ensure constant energy supply for reliable power delivery. Large wind turbines with huge blades can sometimes lead to bird deaths if not equipped with radars. Sometimes it is difficult to integrate wind turbines into existing environment because they can disrupt visual effect of certain landscape.

Wind farms represent a group of interconnected wind turbines on one location which is used for production of electricity. At this moment, the world's largest wind farm is The Roscoe Wind Farm, with the output of 780 MW, in the US state of Texas.

Wind energy has overall positive environmental impact since there are no emissions involved. Certain environmental drawbacks are still present such as the fact that large, fast rotating blades can kill many birds if not equipped with radar, large wind turbines can also create noise pollution which can have negative effect on wildlife in nearby area.

Wind power plant.

GEOTHERMAL ENERGY

Geothermal energy also has relatively long history of use and refers to power extracted from heat stored in the Earth. This heat comes from the radioactive decay of various elements beneath the Earth's surface, volcanic activity, and also from solar energy that was absorbed at the surface. People were first using geothermal energy for bathing, though today geothermal energy is mostly used to generate electricity, though there also some countries that use geothermal energy for heating purposes in form of geothermal heating.

Geothermal energy is renewable energy source that cannot be depleted since earth is in constant state of producing heat (though there can be a factor of temporary local depletion), and it does not produce harmful carbon emissions nor it contributes to air pollution like fossil fuels (coal, oil, and natural gas do). Geothermal energy is clean, cost effective, reliable, sustainable, and environmentally friendly source of energy. Unlike solar and wind energy geothermal energy isn't intermittent energy source and is thus very reliable in terms of supply and delivery.

Geothermal power plants are very expensive to be built costing twice as much compared to coal and natural gas fired plants. High construction and drilling costs are the main reason why geothermal energy is being harnessed in only 24 countries of the world, as it is only being economically acceptable in areas with suitable amount of hot rocks at just the right depth for drilling. Once the drilling technologies become more technologically advanced geothermal energy will likely become much more competitive to fossil fuels.

Three basic types of geothermal power plants are: 1.dry steam plants where steam is piped directly from a geothermal reservoir to turn the generator turbines. 2. flash steam plants that takes the high-pressured hot water from deep inside the Earth and convert it to steam to turn the generator turbines. 3. binary cycle power plants that transfer the heat from geothermal hot water to another liquid, and afterwards the second liquid is turned into the steam that turns the generator turbines.

Geothermal energy is overall environmentally friendly source of energy. Existing geothermal electric plants emit an average of 122 kilograms (269 lb) of CO2 per megawatt-hour of electricity, which represents an amount negligible compared to fossil fuel fired plants. Harnessing geothermal energy has minimal land and freshwater requirements which are drawbacks of solar energy. The only potential environmental threat comes from fluids drawn from the deep earth as they carry a mixture of gases, such as carbon dioxide (CO2), hydrogen sulfide (H2S), methane (CH4) and ammonia which can (if not treated properly) add to global warming, air pollution, and acid rain.

Geothermal power plant.

HYDROPOWER

Hydropower is renewable energy source that has very long history of use, mostly in form of waterwheels and mills. Hydropower is today the most widely spread renewable energy source on global scale supplying around 20% of total global electricity.

Hydropower is renewable energy source that doesn't pollute our planet with harmful greenhouse gas emissions like this is the case with oil, coal and natural gas. Hydropower plants have long lifespan and relatively low maintenance costs since modern technology has enabled that almost everything is automated. Hydropower is very efficient source of energy, and doesn't suffer from intermittency like solar and wind do.

As already mentioned above, hydropower is still the most important renewable energy source on global scale, accounting for approximately 20% of the world's electricity. China currently leads the way in hydroelectricity generation, mostly because of its massive hydropower projects such as Three Gorges Dam.

The largest hydroelectric power plant in the world is Three Gorges Dam in China, with the capacity of 22.5 GW, the second ranked is Itaipu Dam, located between Brazil and Paraguay with the capacity of 14 GW.

The massive hydroelectric power plants can have negative impact on environment if not thoroughly planned and carefully constructed as this was the case with the construction of Three Gorges Dam that led to massive flooding and other negative environmental consequences.

Hydro power plant.

BIOMASS 

Biomass is renewable energy source that refers to biological material deriving from living, or recently living organisms such as wood, waste or biofuels. The five different energy resources from which the biomass derives are wood, waste, garbage, landfill gases, and alcohol fuels.

Biomass is abundant and widely spread source of energy that can be found in almost every corner of the world. Biomass is often said to be carbon neutral energy option, though there are many ongoing studies that still argue whether biomass is really carbon neutral or not. Biomass is also connected with CO2 emissions like fossil fuels are, though it does not contribute to global warming like fossil fuels do because burning of biomass which releases CO2 emissions is said to practically balance the CO2 absorbed by the plants during its growth. Biomass is becoming increasingly popular energy source on global scale, with many countries opening new biomass facilities. Wood is still the most popular form of biomass on global level, though there are many ongoing researches that aim to find the adequate solutions to turn waste and garbage into useful form of energy.

Biomass is said to satisfy today around 4% of US energy needs with more than half of this referring to biomass form using wood. The 2011 US study said that the currently existing biomass power generating industry in the United States has the capacity for around 11,000 MW.

The largest biomass power plant in United States is The New Hope Power Partnership, Florida with the capacity of 140 MW. Biomass power plant size is often driven by biomass availability in close proximity as transport costs of the fuel play a key factor in the plant's economics.

Since wood is the most common form of biomass, unsustainable biomass production could also lead to deforestation which together with the fact that biomass releases CO2 emissions represents environmental drawback of using more biomass.

Biomass power plant.

Solar power - US vs China

Solar energy industry is currently the fastest growing industry in the world, and the most rapidly changing renewable energy sector, where all big countries of the world tend to have their say as much as possible. The economic rivalry between The United States and China has also spread on solar power, and there is an ongoing battle for supremacy in this energy market between these two countries

It has been reported that the United States will likely try to work out a deal that would end ongoing disputes over trade in solar energy products. The European Union already threaten China by saying it would hit back at Chinese solar energy manufacturers for dumping their solar energy products in the European market.

The US did the similar move by the U.S. Commerce Department last year and a senior White House official testified last week that trade policies between countries can only work if they're fair to both countries. The China and the United States are still debating how to best accommodate the other's claims to power, though it seems that the White House may have a few aces up its sleeve to resolve issues related to global renewable energy and trade issues, especially in relation with EU energy policies.

European Trade Commissioner Karel De Gucht has recently complained that Chinese solar panels were sold on the European market below cost on dumping prices which was giving Chinese manufacturers an unfair advantage over the European solar manufacturing companies. In order to counterattack these dumping prices, the EU announced it would impose an 11 percent duty on Chinese solar panel imports. If China still fails to reach a compromise that duty could increase to more than 47 percent by the August.

It is a well known fact that China dominates the global energy market in terms of production of solar panels. The total exports of Chinese solar panels to the European market in 2011, the last year for which information is available, totaled more than $27 billion dollars. Last year, the U.S. Commerce Department targeted Chinese solar manufactures in one of the largest anti-dumping initiatives in U.S. history to protect its solar energy market.  In the United States, China is major player by dominating the solar cell market, with about $3.1 billion worth of goods being imported in 2012.

The Chinese government considers the renewable energy sector, solar power in particular, to be a vital component of its domination in clean energy race. The battle for supremacy on global clean energy market is becoming tenser with each new day, and there still doesn't seem to be the will between all the parties to reach a satisfying agreement as all involved tend to achieve the best possible position on global renewable energy map. Whether there is enough room for both China and United States on top of the hill in terms of renewable energy still remains to be seen. The new trade laws will certainly set the tone, at least short-term speaking.

Geothermal energy – Quick homeowners guide

Geothermal energy is a very interesting alternative to traditional fossil fuels in many parts of the world, not just for the electricity generation but also for heating and cooling purposes. By using more geothermal energy instead of solely relying on coal, oil and natural gas we could help lower global carbon footprint, and thus help our planet tackle the threats of climate change and global warming.

According to a U.S. Department of Energy and Environmental Protection Agency geothermal energy is one of the most efficient and environmentally-friendly options to heat and cool your home. The number of households that employ this source of energy for lowering their electric bill and helping the environment is constantly growing, not just in United States but the rest of the globe too.

The working principle of geothermal energy is not that complicated - geothermal energy uses the natural heat flow inside the earth (from the radioactive decay of elements) for heating and cooling purposes. Geothermal heat pumps, once installed, take heat from underground, and send the energy to the surface to use for heating purposes. For cooling purposes, the opposite is done and the heat is taken away.

The costs of installing geothermal system are significantly higher compared to those of a traditional heating/cooling system, but the total investment will usually be paid off in only a few years’ time – this is since the monthly savings can be pretty substantial because geothermal heating systems are, in average, 50-70% more efficient traditional heating and cooling systems; it has been calculated that some systems can save the homeowners up to 50% on the water heating bill just by preheating the tank water.

Geothermal systems are also connected with easy maintenance and with very little upkeep. In many states there are different manufacturing companies, utilities, and lending institutions that offer rebates and incentives to install geothermal heating and cooling systems.

More geothermal energy instead of staying with fossil fuels does not only mean less greenhouse gas emissions, but also helps lower the threat of ozone layer destruction - by using factory-sealed refrigeration systems.

Geothermal heat pumps are about the size of traditional heating/cooling units. After you install geothermal heat pumps the only costs connected with them will be the electricity that needed to operate the pump, compressor and fan, otherwise they are completely "free" energy. Their electricity needs are fairly low as they do not need large amounts of electricity to function properly.

There are many reasons to give geothermal energy a chance, both economical as well as environmental. The popularity of geothermal energy will no doubt continue to grow in years to come, not just because world is looking for new clean energy solutions, but also because further technological advancement will lead to better cost-competiveness of geothermal systems.