The United States saw its greenhouse gas (GHG) emissions decline last year, according to new analysis last week by the New York-based Rhodium Group, with reductions in the electricity sector coming on strong and fast enough to offset increases in other parts of the economy.

“The results, which estimate a decline in greenhouse gas emissions of around 2% in 2019, contrast with 2018, when emissions rose for the first time in three years,” Greentech Media reports. “Rhodium attributes much of the 2019 turnaround to the electricity sector, where technologies such as wind and solar, in addition to super-cheap gas prices, continued to erode the dominance of coal-fired power.”

But “emissions increases in other sectors tempered the 10% reductions in the power sector,” Greentech adds. “While electricity emissions declined and transportation emissions remained fairly flat in 2019, Rhodium estimates that emissions from buildings, industry, and other sectors increased.”

“It’s a good-news bad-news story,” said report author and Rhodium partner Trevor Houser. “In the electricity sector we had a banner year—we had the largest decline in coal generation in recorded history. But in the other 75% of the economy, emissions remain stubbornly flat.”

The analysis “shows how much coal matters, because in reducing generation from coal we get pretty sizable reductions in the power sector. But at the same time, it shows the limit of coal-led reductions in power, and of the power sector overall, in bringing down economy-wide emissions,” Hannah Pitt, a senior research analyst with Rhodium’s climate and energy group, told Greentech.

“There is only so much you can squeeze out of the power sector before you really need to start seeing reductions in other sectors,” she added.

News lays out the details in the Rhodium report in six charts.

Greentech says the report shines a light on sectors like industry, agriculture, and waste, where “low-cost technology alternatives” aren’t as available or obvious as they are in electricity generation.

“In the power sector, the news is comparatively brighter. According to Rhodium’s estimates, U.S. coal generation experienced a historic year-on-year decline, falling 18% last year,” the industry newsletter states. “Over the whole decade, the U.S. halved its coal generation.”

But while renewable energy “supplemented a chunk of that decline,” Greentech adds, “a sharp decline in gas prices, which were down 20% last year, took a bite out of the emissions reductions tied to coal retirements. Pitt said competition between solar and wind versus natural gas will be a trend to watch,” with renewables now beginning to undercut gas on price.

“As coal retires, there’s an opportunity for those technologies to stand behind it,” Pitt said. But “once we have retired the coal plants we can retire in the U.S., then cheap natural gas could be crowding out cleaner sources in the future.”

In the Rhodium analysis, Grist adds, “surging natural gas was the biggest reason for coal’s demise,” bringing along its own problems with carbon dioxide and methane releases.

And “that’s where policy can play a role,” Greentech says, with the Trump administration rolling back more than 90 environmental rules and regulations, according to tracking by the New York Times. State action can reverse some of that impact, “but if the U.S. is to make the serious changes called for by scientists,” the national government “will have to play a bigger role. Though market forces also contribute, federal policy is ‘the most effective way’ to push emissions down to Paris-acceptable levels, according to Pitt.”

“Nudging people toward clean electricity requires policy: Efficiency standards, building codes, incentives, and taxes,” Grist agrees. “Some state and local governments are making these changes, but at the federal level, the Trump administration is doing its best to stop them. As a result, the country’s energy use seems to have its own laws of motion. It takes a lot of work to change direction, but it’s relatively easy to let things keep running as normal. You can see that in coal’s continued slide, as well as in the status quo in emissions from factories, cars, and buildings.”