- 235. It is a finite energy resource just like the fossil fuels, but nuclear fission releases a vast amount of energy. For example, 1kg of coal has enough energy to keep a bright light bulb running for 1000 hours. 1kg of uranium 235 keeps the same light running for 10 million hours.
Although nuclear fuels are relatively cheap the total cost of generating electricity using nuclear fuels is high. This is because of the cost of building, and decomision the plants themselves and disposing the safely.