Nuclear energy is necessary to fight climate change and decrease fossil fuel use. Wind and solar are distributed energy sources which are intermittant and variable. Nuclear, however, is continuously available and represents a much more concentrated source of energy, with a much higher capacity. Both nuclear and renewable energy's contribution to energy production on the planet must increase exponentially in order to significantly cut down the share of fossil suels in the world energy mix.
In order for the entire planet to achieve at least 25% greenhouse gas (GHG) reduction by 2025, nuclear energy is going to have to augment truly clean, renewable energy in the effort to dramatically reduce fossil fuel use. Once it’s at the operational stage, carbon dioxide emissions from a nuclear reactor and the power plant’s site are minimal. Other than reduction of emissions, nuclear offers, by far, the most energy dense resource available. Fossil fuels are more energy dense than renewable energy sources, but 1 kg of coal can only keep a lightbulb lit for a few days, while the same quantity of a nuclear energy source will keep it lit for well over 100 years. Nuclear does this without any CO2, or most other GHG, emissions from the nuclear plant.
Current reactors, 2nd and 3rd generation plants, rely on water and uranium. Therefore, these nuclear plants still deplete water supplies, create nuclear waste, use a fuel source that can be enriched to convert the material into a bomb, and represent a source of potential danger, as in the Fukushima disaster (although this risk is dramatically minimized in a 3rd generation plant). A safer, cheaper, and still energy abundant and emissions-free design that uses relatively benign energy sources and relatively much less water than previous designs and operational plants, is becoming available in 4th generation nuclear.
Using very little water, the 4th generation designs are safe, cost- effective, environmentally-friendly and still energy-dense. Molten salt reactors using depleted uranium, nuclear waste, from other plants are being designed as 4th generation nuclear plants. 4th generation designs are autonomous, smart plants that are even being designed to run on different fuel sources. Thorium, instead of uranium, is being looked at as a fuel source, as it is abundant, much less radioactive than uranium, and also creates by-products from burning the fuel source, that can just be used again in the reactor. Thorium reactors are being designed with low up-front capital costs, and little manpower needs to run and maintain the plants, due to the advanced computer technology set to be deployed in the plants. Thorium, and depleted uranium, have a very low chance of being developed into a nuclear weapons, produce less radioactive waste, are abundant fuel sources, and are safer, cheaper and cleaner.
Thorium, in particular, is being looked at by developing nations like China and India because of the relatively low cost, increased safety, abundance of the material, and tremendous energy potential of this energy source. The U.S. has huge stockpiles of thorium, in places like Idaho, and there are large stockpiles in countries like India, Australia and Brazil. The U.S., Europe and even some of the aforementioned developing countries also have large stockpiles of depleted uranium, with more being produced every day, which would work in many of the 4th generation designs. 4th generation nuclear promises to produce abundant, low-cost energy safely, and with little environmental impact.