The U.S. in 2017 continued its trajectory toward a transforming energy economy by amping up renewable power output and new natural gas installations while curbing greenhouse gas emissions to levels not seen since 1991, despite the Trump administration's efforts to roll back key environmental regulations.
Renewable power generation shot up 14% to an estimated 717 TWh in 2017 thanks to increased production by hydroelectric power in Western states that saw a slight reprieve from a prolonged drought, according to the "2018 Sustainable Energy in America" report released Feb. 15 by Bloomberg New Energy Finance and the Business Council for Sustainable Energy. About 18,400 MW of new renewables came online in 2017, while purchase agreements for offsite renewables rose to 2,900 MW, which was the second-highest year on record since 2015, when 3,200 MW of new deals were signed.
While global clean energy investment rose to $333 billion, the second-highest amount on record, U.S. investments tracked 2016 levels at $57 billion but saw a shift in capital deployment toward wind and energy smart technologies, the report said.
All this growth "has happened during a year of change for sustainable energy policy" including the U.S. Environmental Protection Agency's proposed rollback of the Clean Power Plan, regulatory actions by other agencies, solar trade case tariff proposals and tax reform, Rachel Luo of Bloomberg New Energy Finance said Feb. 15 at a press briefing on the report in Washington, D.C. "There has been a lot of uncertainty and yet the [clean energy] sector has continued to make progress."
Industry officials said tax reform talks and the four-year tariff on certain solar imports that President Donald Trump put in place in January, combined with the looming action on that case in 2017, dampened growth.
"On the solar side, I think we're going to continue to grow," said Abigail Ross Hopper, president and CEO of the Solar Energy Industries Association. "We'll still see a little over 10 GW of new solar capacity in 2018, but it could have been more" if not for the tariff import decision.
Tom Kiernan, CEO of the American Wind Energy Association, said that for the wind industry during tax reform discussions, "it was sort of pens down" on new projects but that industry has picked back up now that a bill passed that left the wind tax incentives phaseout deal from 2015 intact.
American Gas Association President and CEO Dave McCurdy defended some of the actions as necessary, including the administration's efforts to streamline pipeline permitting. More broadly, on regulatory reforms, McCurdy said, "We didn't support all of them."
Natural gas power plants, which generally emit less carbon dioxide than coal, are playing a role along with renewables and energy efficiency in filling the supply gaps as coal-fired plants retire thanks, in part, to low gas prices tied to increased hydraulic fracturing. Natural gas-fired power retained its position as the top U.S. power producer, contributing 32% of the electricity mix in 2017, and saw 10,700 MW of capacity, its best year since 2005. Liquefied natural gas and pipeline exports to Mexico increased net export volumes to 2 Bcf/d as of the end of November 2017, compared to an average 0.03 Bcf/d of net imports for the same period in 2016.
Coal-fired generation retirements are showing no sign of slowing despite Trump's pledge to restore the industry to its former glory. Coal plant owners by the end of 2017 had announced 12,500 MW of planned retirements for 2018, "foreshadowing the largest year for coal decommissioning since the 15 GW of retirements in 2015," the report said.
U.S. greenhouse gas emissions fell 1.4% year on year to 6.4 gigatonnes of carbon dioxide equivalent in 2017, putting the nation about halfway to its target under the Paris Agreement on climate change of slashing economywide emissions to 26% below 2005 levels by 2025. Trump has pledged to withdraw the U.S. from the climate accord. Power sector emissions in 2017 were 28% below 2005 levels, which is only 4 percentage points away from achieving the overarching Clean Power Plan's target of reducing emissions 32% below 2005 levels by 2030.
The transportation sector in 2016 overtook power as the largest greenhouse gas emitter, although both sectors together still account for about 60% of emissions. Most scientists have linked greenhouse gas emissions to climate change.