U.S. natural gas to pass coal as electricity fuel in 2035

Coal will continue to fuel the largest share of electricity generated in the U.S. until 2035, when natural gas will surpass it, according to a recent federal report.

The U.S. Energy Information Administration's 2014 Annual Energy Outlook presents a long-term forecast of energy supply, demand, and prices from the present through 2040.  Its scope includes predictions about shifts in the portfolio of types of electricity generating resources used to produce power.  The largest such trend projected in EIA's 2014 report is that the market share of coal and nuclear generators will likely decline over the next two decades, as natural gas-fired and renewable electricity sources grow in prominence.

Historically, coal has fueled the largest share of electricity generated in the U.S.  Typically operating as baseload generation, coal has traditionally been a relatively low-cost fuel for electric production.  Coal's share of the electricity mix peaked in 2007, at 49% of all electric power generated.  Since then, coal's share has declined; in 2012, coal-fired generators produced 39% of all electricity generated by utilities -- still the largest piece of the generation portfolio, despite a significant decline.

Coal's role in the nation's energy mix is under challenge from multiple fronts.  Economically, the increased availability of lower-cost natural gas has made coal less competitive.  Meanwhile, tighter environmental regulations -- such as the U.S. Environmental Protection Agency's Mercury and Air Toxics Standards, or MATS rules -- have placed additional pressure on coal plant operators to either invest in upgraded environmental controls or shut down.

At the end of 2012, 310 gigawatts of coal-fired generating capacity was available to run in the U.S.  Of that, EIA projects that 50 gigawatts will be retired by 2020 under its base case model.

Under EIA's model, natural gas will grow its market share while coal declines.  EIA projects that 70% of all new capacity added before 2040 will be fueled by natural gas.  If EIA's assumptions hold, natural gas will surpass coal as a fuel for electricity generation in 2035.

While EIA's model rests on a series of assumptions, all of the alternative cases examined by EIA assume that coal-fired capacity will be retired, while natural gas-fired and renewable generation will grow.  What will the future hold for the U.S. energy mix?