Exxon Mobil's latest energy outlook forecasts that power generation in the U.S. will continue to shift toward natural gas, nuclear and renewables over the next few decades. U.S. use of nuclear power is projected to rise 25% from 2025 through 2040 and overtake coal as a source of energy production. Increased use of nuclear fuel is likely to be a catalyst for growth of nuclear decommissioning trusts - funds set aside to decommission plants and cleanup radioactive waste. Pensions & Investments estimates total assets of nuclear decommissioning trusts to be more than $55 billion.