Coal is still king in Kentucky, but its reign as the state's main energy source is slipping.

Over the past five years, the state has made its first significant shift away from coal power, thanks to cheaper natural gas. The move comes as the Green New Deal and its ambitious policy proposals push conversations about Kentucky's energy future further into the political arena.

The plan, introduced and backed by Democrats in Congress, aims to set the U.S. on a course toward an energy infrastructure that produces no emissions and relies entirely on renewable power.

In other words, an energy future without coal.

Kentucky has legislation to encourage and allow renewable energy, but it hasn't seen the same level of development as other states, said Tom FitzGerald, director of the Kentucky Resources Council.

"It's an interesting picture," he said of Kentucky's willingness to adopt renewable energy. "The utilities are starting to move to expand their portfolios with some solar."

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But FitzGerald said the state's adoption of renewable energy has been slowed to an extent by the availability of cheap natural gas. That same availability has fueled the state's shift from coal in recent years.

Still, experts say coal will have a place in Kentucky's energy future for at least several more decades.

"It's hard to turn your back on something you have," said Chuck Hookham, who works on energy development projects for a developer and utility in Michigan. "It would be like if you had a huge uranium pile, would you want to put in nuclear (energy plants)? Well yes, because you have the resources in the state. You have a low-cost supply.

"But you have got to look at the environmental and sustainable impacts."

Coal is slipping in Kentucky

Between 2001 to 2014, more than 90% of Kentucky's energy supply came from coal.

In 2015, coal had dipped below 90% for the first time, and by 2018 just 75% of the state's energy came from coal.

Most of the drop can be traced to natural gas use, which rose from 2.4% of the state's energy in 2014 to 18% in 2018.

Creating an energy infrastructure that produces no emissions, as called for in the Green New Deal, likely is "insurmountable" with current technology, said Rodney Andrews, director of the University of Kentucky's Center for Applied Energy Research.

"If we want to do better than what we have able to do, we need to make an investment in new technologies," he said. "If we want unlimited free energy, we need to come up with something better than we have now."

From 2015 to 2018, hydroelectric power increased its share of the state's energy production by only 2%. The gains there, Andrews said, will come from better technology, not more facilities, which also could lead to more solar and wind in the state.

"A moon shot for energy, that would be great," he said. "But the scale of it is something I don’t think people understand."

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Green New Deal is 'a utopian vision'

Some might argue that the Green New Deal sets up that moon shot. However, the plan also includes proposals such as guaranteed jobs and strengthened laws for unions.

As a result, U.S. Rep. John Yarmuth, D-Louisville, said he would like to see the true energy and climate provisions of the plan pulled into a separate plan.

"I think it's a utopian vision for the country and there are a lot of very, I think, important goals in that vision," he said. "I don't think it's something that is actually possible to do, to implement within the time frame that's mentioned."

Yarmuth said he expects coal to continue its decline and eventually have no role in Kentucky's energy generation as battery storage technology and advancements in the electric vehicle industry improve.

"I think the future for renewables is becoming more and more promising a lot faster than, I think, a lot of people anticipated it would," he said.

Almost certainly, Kentucky's shift from coal is unlikely to reverse course, since coal-fired plants have been closing.

"You have a mix of events and occurrences that do not bode good for coal," said Jim Wood, the interim director of the Energy Institute at West Virginia University.

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Could foreign markets help save coal?

"I know there's a lot of research going on on what else can we do with coal … but that's going to take some time. There's going to need to be a market. There's going to have to be economics involved. ... I don't see, in the near term for sure and probably out over a decade or more, I don't see much going on that's going to help coal."

There is one possible future for coal, Wood said, if it can be mined and exported to international markets in countries putting less focus on the environmental impacts of burning it for energy.

"I think that states like Kentucky and West Virginia are going to have to suffer through the loss of jobs," he said. "And those jobs that continue to be in the industry are going to be jobs related to mining and export."

Kentucky's drop in coal reliance is reflected in the Louisville area: Louisville Gas & Electric generated 98% of its production from coal in 2009, but 80% today, company spokesman Daniel Lowry said.

The bulk of that drop has been made up by an increase in natural gas, although the utility is investing in renewable energy, he said.

Pennsylvania-based PPL Corp., which owns LG&E, has committed to reducing carbon emission levels by 70% from 2010 levels by 2050, Lowry added. Utilities across the country have made similar promises.

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However, the shift to natural gas has been more about economics than an effort to reduce harmful emissions, said Jay Apt, co-director of Carnegie Mellon University’s Electricity Industry Center.

Maintenance costs for a coal plant are about 10 times those for natural gas plants, he said, and while there are pollution controls for coal plants, the economics of natural gas has pushed it ahead.

For a sense of what Kentucky's energy future could look like, Apt pointed at Germany, a country that relieved heavily on coal and now produces about 40% of its energy from renewable resources.

Germany made the invests in renewable energy, and Apt said the U.S., which gets about 17% of its energy needs from renewable sources, can make ground in the area before seeing any significant cost increase.

However, he said there will always be a need for maybe a quarter of the energy coming from nonrenewable sources such as coal or natural gas, because solar and wind are not as reliable.

Can technology make renewables competitive?

Any sustained effort to increase renewable energy will have to be coupled with improved technology, specifically storage. Battery storage is expensive but improving as East and West coast states, where energy costs more, look to upgrade their infrastructure.

Those technological advancements take time, as do advancements that could make geothermal, solar and wind more reliable and productive for Kentucky.

Parts of the Green New Deal discuss the need to emphasize these technological advancements. It calls for upgrading energy production, moving to "smart" energy grids and updating or constructing buildings for maximal energy efficiency.

Energy efficiency already is one way that gains have been made in Kentucky and across the country. Areas have started moving toward "smart" grids, a catchall term for adding to older grids — the wires and transformers — to better manage energy flow and reduce or shorten outages, said Hookham, the Michigan-based energy project developer who has worked in Kentucky.

Those upgrades likely will drive up the costs, which can present utilities with difficult choices, but Hookham said there appears to be a willingness in the state to pursue more environmentally friendly alternatives.

"I think there's a mind-set that slowly kind of creeps into the discussion, which is we have to start doing something, there has to be a sustainable solution," he said. "The coal reserves won't last forever."

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Matt Mencarini: 502-582-4221; mmencarini@courierjournal.com; Twitter: @MattMencarini. Support strong local journalism by subscribing today: courier-journal.com/specialoffer.