Inside the troubling rise of CO2 at power plants

Source: By Benjamin Storrow, E&E News reporter • Posted: Friday, January 11, 2019

The power sector has long been the engine behind America’s reduction in carbon dioxide emissions.

Not anymore.

A recent analysis from the Rhodium Group, an economic consulting firm, estimates that carbon emissions from U.S. power plants increased 1.9 percent in 2018. That would mark the first emissions bump from the sector since 2013, when carbon levels rose slightly.

The development contains several worrying signs for environmental advocates. Greening the power sector is relatively easy compared to transportation and the residential and industrial sectors of the economy, where low carbon alternatives to fossil fuels are limited and more costly.

And failing to limit carbon emissions from power plants makes it more difficult to clean up tailpipes, buildings and factories. Most deep decarbonization scenarios envision using large amounts of wind, solar and other non-emitting sources of electricity generation to power cars and trucks, heat and cool homes, and fuel factories.

“To get anywhere near our climate goals, we need our electric grid to be dramatically cleaner than it is today,” said Daniel Cohan, a professor at Rice University who studies the power sector.

If power plants fail to clean up faster than other sectors of the economy, meeting the 26 percent reduction in emissions envisioned by the Paris Agreement “becomes impossible,” Cohan said.

American utilities have made impressive progress in cutting their carbon output in recent years. Emissions from power plants fell 28 percent between 2005 and 2017, according to federal figures. Total energy-related emissions, by contrast, were down 14 percent.

The trend made the power sector a bright spot for greens who are distraught by President Trump’s dismantling of environmental protections and his promotion of coal. In 2017, the U.S. was one of a few countries worldwide to post a reduction in carbon levels, thanks in large part to the continued decline in emissions from power plants (Climatewire, March 23, 2018).

Much of those reductions came as utilities traded coal plants for facilities fueled by natural gas. The U.S. Energy Information Administration estimates that coal to gas switching accounted for roughly two-thirds of all power sector emission reductions between 2005 and 2017.

But last year illustrated the limitations to that approach as a climate strategy.

Coal plant retirements approached record highs (Climatewire, Jan. 2). But falling emissions from coal plants were offset by natural gas generators, which ran harder to satisfy an increase in electricity demand.

Rhodium’s analysis found that coal generation fell by 52 kilowatt-hours in the first 10 months of the year, while gas generation rose 166 kWh. Power sector carbon emissions increased by 34 million tons as a result, helping fuel an estimated 3.4 percent increase in overall U.S. carbon emissions (Climatewire, Jan. 9).

“Gas has been rising to the challenge of meeting demand in 2018 in a way it hadn’t needed to in the past because electricity demand hadn’t risen as quickly,” said John Larsen, a former Department of Energy official in the Obama administration who leads Rhodium’s power sector research.

Part of the demand spike could be temporary. A hot summer and cold winter last year, combined with a galloping economy, meant demand for power outpaced gains in energy efficiency, which has helped mitigate rising electricity use in recent years.

Other factors point to the difficult challenges facing climate hawks. Little coal remains in the Northeast and on the West Coast, meaning future carbon reductions will have to come from elsewhere, said Jesse Jenkins, a researcher at Harvard University.

“The low-hanging fruit, swapping out coal for some combination of natural gas and renewables, is starting to get picked,” Jenkins said. “Now, the challenge is to displace gas plants with low-carbon resources.”

Whether America can add enough renewables to significantly reduce gas generation and its resulting emissions is an open question. EIA estimates that wind will account for 46 percent of all new power plant capacity in 2019, the last year for the federal wind production tax credit. Gas and solar, by comparison, represent 32 percent and 18 percent of new capacity, respectively. But gas overtakes wind as the top source of new capacity in 2020 and 2021, according to federal projections.

When renewables are brought online, their emissions impact could be mitigated by the retirement of nuclear plants. Offshore wind in the Northeast will largely replace power from a series of retiring nuclear facilities in the region, analysts noted.

The dynamic speaks to the continued need for new policies to drive power sector reductions, they said. California recently passed a bill requiring all of its electricity to come from carbon-free sources by 2045. And several newly elected Democratic governors have signaled they intend to follow suit with similar plans.

But analysts said action at the federal level is needed to ensure that emissions reductions from the power sector don’t stall out.

“We’ve been saying there will be a limit to what increasingly cheap renewables and continuously cheap natural gas can deliver with respect to emissions,” Larsen said. “We’re not done yet.”