One of these options is definitely nuclear energy. Unfortunately, nuclear energy still suffers because of its former sins (Chernobyl, Three Miles Island), and many think of only Chernobyl disaster when thinking about nuclear energy. But truth is completely different, and today with maximum safety measures on, nuclear energy is definitely worth to consider. Nuclear energy sector has learned from mistakes and today we are talking about nuclear power plants with maximum safety, with literally no chance of another Chernobyl disaster. From the ecological point of view nuclear energy is ecologically acceptable energy source, for instance it creates less than 1/100th of the CO2 created by the traditional power plants.
There are two well known processes in producing nuclear energy - fission and fusion. Fission, which is the splitting of nuclei, is highly efficient process that creates more than 10 million times the energy compared to the energy created in the burning of the same amount of fossil fuels. Fusion is the opposite, the process of joining nuclei that happens naturally in stars and the sun; though fusion process has been recreated in laboratories, it is not ready yet for mass energy production. Once this happens the amounts of usable nuclear energy will dramatically increase.
Currently, there are 442 nuclear fission reactors operating in the world, of which almost one third (130) is in the United States. With the current technology, thermal reactors can capture only 1% of the energy available in uranium. This energy makes up between 11% and 18% of the total energy available in the world. Developing technologies that would allow us to capture more of this available energy are still couple of decades away but nonetheless nuclear energy has big potential.
Nuclear fuel cycle. Uranium is mined, enriched and manufactured to nuclear fuel (1) which is delivered to a nuclear power plant. After usage in the power plant the spent fuel is delivered to a reprocessing plant (2) or to final repository (3) for permanent storage in a safe place, such as inside rock. In reprocessing 95% of spent fuel can be recycled to be returned to usage in a power plant (4).
Uranium is the main source of nuclear energy (large uranium deposits are found in Australia). Mining uranium is not too expensive, and the additional advantage of uranium is very easy transport to reactors anywhere in the world. This of course makes nuclear energy relatively inexpensive to produce when not only compared to conventional methods of energy production, but also to some renewable energy sources. Cost of nuclear energy is between 3 and 5 cents per kilowatt hour, and the developing technologies have seen this cost to be dropped over the last 25 years, unlike the cost of other forms of energy that have steadily increased over the same period of time.
With these advantages, and relatively low incidence rates, nuclear energy is definitely one energy source we should be thinking much more in years to come.