For people who devour energy data like Thin Mints, last week was a special one, with the release of a trove of numbers from the Energy Information Administration showing us how 2019 fits into the bigger picture of the transition to clean energy.

Natural gas remained the leading fuel for electricity, used to generate 38 percent of the country’s total in 2019, up from 35 percent in the prior year, thanks to very low market prices for gas and a building spree of new gas plants.

Next was coal, with 23 percent, down from 27 percent, continuing a long-term decline. Nuclear accounted for 20 percent, about the same as the prior year, followed by renewables, with 17 percent, which I’ll tell you more about in a minute. That leaves about 1 percent to “other,” which includes other gases and oil.

But the most interesting story is not the one-year changes, but how 2019 helped to reinforce some of the longer-term trends we’ve been watching.

Here are five takeaways, with graphics from ICN’s Paul Horn:

The electricity sector is responsible for more than one-fourth of all of U.S. carbon emissions, ranking just behind transportation as the leading emissions source.

For the country to stave off the most harmful effects of climate change, the sector would need to get its emissions to zero, or close to it, as soon as possible, and the transportation sector would have to make a shift to using electricity, rather than gasoline, as a default fuel.

The chart above is a good indicator of how well we’re doing in making this transition in the electricity sector. There is clear progress, but it’s moving much more slowly than many climate scientists say is needed.

Here’s a big fat positive indicator for you: Coal, a severe climate hazard because of its high emissions, is retreating from the market. At the same time, renewables are rising.

Coal is on the decline because coal-fired power plants cost more to operate than those fueled by natural gas, wind and solar. No new coal plants are being built, and many existing plants are closing.

The line for renewables may look oddly flat, considering that wind and solar have been growing at a rapid rate. The thing to remember is that hydroelectric power is more than one-third of the total and it has not been growing, so the increase is less dramatic than if the category was limited to wind and solar.

Solar is growing like crazy, but its total in 2019 of 107,275 gigawatt-hours is still a tiny share—3 percent—of the country’s total.

To take action to fight climate change, utilities, developers and private owners will need to build a lot more than is in place today. The low cost of solar panels and the versatility of the systems—they are capable of being placed in utility-scale arrays and on roofs of homes and businesses—mean there is a giant upside in how big the country’s solar market can get.

We also can see diversification in where solar projects are happening compared to 2014, with California occupying a smaller share and the rest of the United States growing by leaps and bounds.

Wind energy generates more than twice as much electricity as solar, but it’s not growing nearly as fast. Some of the best prospects for growth are in offshore wind, which now includes just one small project in Rhode Island but is in the process of ramping up to become the engine of the U.S. wind industry, with projects in various stages of development along the East Coast.

This last chart shows the least dramatic shift, and that’s a good thing. The U.S. has gotten much better at conserving energy, using more efficient lighting and appliances, and improving building codes, among many other changes. This means that the country’s total electricity demand has been essentially flat since about 2010.

The lack of growth in demand is crucial for keeping emissions in check, because increases in demand will be met by the building of new power plants or running existing plants more often, and in many places that means burning more natural gas and other fossil fuels.

Some technical notes: These figures come from the most recent edition of EIA’s Electric Power Monthly, which was the first to have full-year numbers for 2019. Some of the numbers are preliminary, meaning they may be updated, and the numbers in all the charts have been rounded.

I’ve written before about the criticism of how EIA’s long-term forecasting has been slow to recognize the pace of the energy transition. It’s important to distinguish the current data used in the charts above, which is tremendously valuable, from the long-term forecast.

Report: The Building Boom of Natural Gas Power Plants is Bad—for Investors

One of the factors limiting the speed of the transition to clean energy in the United States is the continuing proliferation of natural gas power plants.

But that increase may be time-limited. A report released Wednesday says that investors in the companies building natural gas plants are setting themselves up for future financial losses.

“States and cities in the U.S. are increasingly saying they’re not willing to have fossil fuels in the grid by 2050, and I don’t see that trend slowing,” said Michael O’Boyle, a co-author of the report, and director of electricity policy for the think tank Energy Innovation.

A clash with state and city policies is just one of many factors cited in the report, issued by Energy Innovation and the investor-focused activist group As You Sow. The underlying idea is that new power plants, with expected lifetimes of 30 years or more, are not compatible with the idea of drastically reducing carbon emissions and fighting climate change.

I’ll be watching for evidence that this kind of message is getting through to investors, not just climate-focused activists but also institutional investors, whose interests are almost completely financial.

South Dakota to Get Its First Super-Size Solar Array

Geronimo Energy is a good example of how large solar projects are showing up across the country.

The company said this week that it has an agreement to build a 128-megawatt solar array in South Dakota, a place not known for being sunny.

The project, to be located about 20 miles east of Rapid City, is on a scale unheard of, in a state that now has just 1.8 megawatts of solar, according to the Solar Energy Industries Association, which ranks South Dakota 50th out of 51 states and the District of Columbia.

Minnesota-based Geronimo will be developing the project for use by Basin Electric Power Cooperative, a company that generates electricity for rural electric cooperative utilities across nine states.

Geronimo has a track record as a pioneer in new solar markets. It is developing a 200-megawatt solar project near Grand Forks, North Dakota, that will be the largest in that state.

Inside Clean Energy is ICN’s weekly bulletin of news and analysis about the energy transition. Send news tips and questions to [email protected].