“Trump Digs Coal” read the signs during the campaign, and Donald Trump promised he would be “an unbelievable positive” for the miners. Now he’s trying to deliver by repealing the Obama-era Clean Power Plan and proposing to subsidize coal-fired power plants. These moves are, in fact, unbelievable: Not only are they a setback in the fight against climate change, but they also make no economic sense, since the cost of renewable energy is falling sharply.

1. Trump can’t save coal. He only claims he can.

On Tuesday, the Environmental Protection Agency published its proposal to undo the Clean Power Plan without putting anything in its place. The plan was one of the most important parts of former President Barack Obama’s commitment under the Paris climate agreement to cut United States greenhouse gas emissions by 26 percent to 28 percent below 2005 levels by 2025. The plan was meant to accelerate emission reductions in the power sector.

Power sector CO2 emission projections Million metric tons 2014 projections HISTORICAL emissions 2,000 Projections without cpp EPA TARGET: 32% below 2005 levels 1,500 1,000 2005 ‘10 ‘15 ‘20 ‘25 ‘30 Note: 2014 projections based on Annual Energy Outlook. Sources: Energy Information Administration (historical, 2014 projection); Rhodium Group (current projection without CPP) Power sector CO2 emission projections Million metric tons 2014 projections 2.0K HISTORICAL emissions Projections without cpp EPA TARGET: 32% below 2005 levels 1.5K 1.0K 2005 ‘10 ‘15 ‘20 ‘25 ‘30 Note: 2014 projections based on Annual Energy Outlook. Sources: Energy Information Administration (historical, 2014 projection); Rhodium Group (current projection without CPP)

Earlier, Mr. Trump’s energy secretary, Rick Perry, asked the Federal Energy Regulatory Commission to come up with rules that would require businesses, consumers and anybody else who uses the electricity grid to pay coal-fired plants to be ready to supply power whether that energy was needed or not. He claims such payments will make the grid more “resilient” — many experts doubt that.

Taken together, these proposals are a brazen attempt to promote one source of energy over others — a criticism that conservatives often lobbed at Mr. Obama for his attempts to do something about climate change. In fact, tied up in court, the Clean Power Plan has not even gone into effect.

2. Coal use is declining. Meanwhile, use of other energy sources has risen sharply.

Coal has been falling out of favor because utilities are switching to natural gas, which has become much cheaper in recent years thanks to a boom in shale production.

Megawatt-hours of electricity production, by energy source 2b 1.5b Coal Natural gas 1b Nuclear Hydro- electric 500m Wind Other 0 1990 1995 2000 2005 2010 2015 Source: U.S. Energy Information Administration Megawatt-hours of electricity production, by energy source 2b 1.5b Coal Natural gas 1b Nuclear Hydro- electric 500m Wind Other 0 1990 ‘95 2000 ‘05 ‘10 ‘15 Source: U.S. Energy Information Administration

3. Renewable energy is coming on strong. Mostly because producing it is getting cheaper.

The worldwide average cost of wind and solar power has fallen sharply over the last three years, according to a recent report by the International Energy Agency. While these sources of energy make up a small portion of the overall system — for example, about 15 percent of electricity generated in the United States last year and 24 percent generated worldwide — they are growing fast: Two-thirds of generation capacity added globally last year came from renewable sources.

Price per solar module PRICE PER WATT $2 RANGE OF Typical module priceS Average price 1 Projection 0 2010 ‘11 ‘12 ‘13 ‘14 ‘15 ‘16 ‘17 ‘18 ‘19 ‘20 ‘21 ‘22 Notes: A module is made up of the solar cells that convert light into electricity. Includes photovoltaic modules. In 2016 dollars. Source: International Energy Association Price per solar module PRICE PER WATT $2 RANGE OF Typical module priceS Average price 1 Projection 0 2010 ‘12 ‘14 ‘16 ‘18 ‘20 ‘22 Notes: A module is made up of the solar cells that convert light into electricity. Includes photovoltaic modules. In 2016 dollars. Source: International Energy Association

4. Wind and solar are becoming cheaper. They’re expected to be cheaper than other sources for years to come.

In some countries like India, the United Arab Emirates, Mexico and Chile, auction prices for renewable energy have fallen so much that they are “comparable or lower than generation cost of newly built gas and coal power plants,” according to the agency, which researches the energy sector for 29 member countries, including the United States. Based on current trends, the agency forecasts that the cost of land-based wind turbines and utility-size solar projects will fall an additional 15 percent and 25 percent, respectively, in the next five years.

Average solar system prices $6k/kW Residential Utility-scale 2015 5k ‘16 4k ‘22 3k 2k 1k Japan Korea U.S. Aus. China Ger. India Notes: A module is made up of the solar cells that convert light into electricity. Includes photovoltaic modules in 2016 dollars. Source: Analysis based on IRENA; International Energy Association Average solar system prices $6k/kW Residential Utility-scale 2015 5k ‘16 4k ‘22 3k 2k 1k Japan Aus. U.S. Korea $2k/kW 1k China Ger. India Notes: A module is made up of the solar cells that convert light into electricity. Includes photovoltaic modules in 2016 dollars. Source: Analysis based on IRENA; International Energy Association

In the United States, developers of new wind farms signed contracts to sell power at around $20 per megawatt-hour last year, down from about $61 per megawatt-hour in 2010, according to a recent report by the Energy Department.

Wind contract price, national average $60 40 20 $22.02 0 2010 2012 2014 2016 Note: Contract price is the power purchase agreement, generation-weighted average. Source: U.S. Department of Energy Wind contract price, national average $60 40 20 $22.02 0 2010 ‘12 ‘14 ‘16 Note: Contract price is the power purchase agreement, generation-weighted average. Source: U.S. Department of Energy

That report also points out that these prices are lower than those for electricity from natural gas plants and are expected to stay that way for years to come. That’s because wind power contracts lock in low prices for 20 years or longer, whereas the cost of natural gas fluctuates from day to day. Developers of wind farms — and solar projects — do receive federal tax credits, but those subsidies are being phased out and will be eliminated in 2020.

5. Technology is helping renewables. It’s getting easier to produce renewable energy.

Wind turbines and solar panels cannot produce electricity at all times in all weather conditions. But there have been great technical strides that have improved their performance. For example, modern wind turbines are much more productive than the turbines installed just one decade ago.

What’s more, batteries have become much cheaper, making it less expensive to store electricity when it’s windy or sunny for times when it is not. The average cost of lithium-ion batteries fell 73 percent, to $273 per kilowatt-hour, between 2010 and 2016, according to Bloomberg New Energy Finance.

Lithium-ion battery price $1,000 per kWh 800 600 400 $273 200 0 2010 2011 2012 2013 2014 2015 2016 Note: Includes cells plus pack prices Source: Bloomberg New Energy Finance Lithium-ion battery price $1,000 /kWh 800 600 400 $273 200 0 2010 ‘11 ‘12 ‘13 ‘14 ‘15 ‘16 Note: Includes cells plus pack prices Source: Bloomberg New Energy Finance