An area roughly the size of Cherokee Park would be required to supply and store the needed power to meet the studied area’s demands, the LG&E study shows. | Courtesy LG&E

What would it take to power Louisville solely by the sun? Probably more land and money than customers would bear, according to the city’s power and natural-gas provider.

In a study released Thursday, LG&E analyzed a roughly 316-acre section of the Highlands to see what would be required to cut it off from the grid and power it just with solar panels, backed up by batteries. The study says it would take an area roughly the size of Cherokee Park and cost about 2.5 to 3.5 times as much money in 2030 as sticking with the LG&E system.

While the technical challenges could probably be overcome, “doing so would require a large geographic space…that would result in land being used for solar panels and battery storage on a scale that would likely not be acceptable to the local community,” the study says.

The study by the unit of Allentown, Penn.-based PPL Corp. comes as environmental groups urge the Louisville Metro Council to adopt a nonbinding resolution for the city to quit using fossil fuel-fired electricity and to power all of its operations with renewable energy by 2030 — with the rest of the community following suit five years later.

The council’s Committee on Sustainability and Parks on Thursday heard advocates make a second pitch to switch the metro area to all-green electricity. The proponents laid out various technologies such as photovoltaics, wind generation, landfill-gas capture and advanced efficiency efforts that could be used to meet the target. Committee members tabled the resolution and will pick it up to discuss in the new year.

“There is no shortage of energy options for us, but a shortage of political will,” said Tim Darst, executive director of Kentucky Interfaith Power and Light, which works with houses of worship on sustainability issues. Darst later said proponents of the resolution aren’t pressing to power Jefferson County just with local solar power, but want to set the goal and then bring in different groups to figure out the most economic way to reach it.

“There’s not one way to do it and we’re not saying we know the best way to get there,” he said. However, slashing demand with efficiency incentives would be a smart first step. 

LG&E and KU has cut some efficiency incentives, saying they didn’t make economic sense.

David Sinclair, LG&E and KU’s vice president of energy supply and analysis, told committee members that cutting greenhouse-gas emissions might be a more realistic goal than striving strictly to go all-renewable.

“You don’t want to let the perfect be the enemy of the good here,” he said. “I would think it would be more important to focus on CO2, rather than the means by which you do it.”

key U.N. panel warned in October that drastic changes to society were needed to stave off the worst effects of climate change. Although that report’s stark appraisal was echoed in a big U.S. government climate assessment released last month, President Donald Trump dismissed the reports, and his administration has stepped back from efforts to fight climate change.

LG&E analyzed 2017 data for the distribution circuit Highland 1103, which lies mostly between the south edge of Cherokee Park and Bardstown Road, because its mix of about 1,600 residential and 240 small commercial customers was typical for Jefferson County.

The company estimated the all-in retail rate to be paid by consumers, assuming an increase ranging between 2 percent and 5 percent a year. (Since 1990, LG&E’s rates have gone up an average of 2.1 percent a year.) At the midpoint of the forecast range, going totally solar with batteries in 2030 would cost 44.7 cents a kilowatt hour, versus 16.8 cents/kWh to stick with the LG&E system, the company said.

With solar and battery costs forecast to keep dropping, “waiting as long as possible to make such investments would increase the probability of being economical compared to the LG&E system rates,” the study says. 

One of the biggest challenges to going pure solar, the study shows, is having sufficient generation in place to make sure batteries have enough juice to meet nighttime demand and to guard against short, overcast winter days. To cover those periods, it would take eight times as much solar generating capacity as would be needed to power air-conditioners at the peak of summer demand, the study says. And that’s even with customers using gas to heat their homes and water.

In winter, “because the sun is not very high in the sky very long, there is no supercharger, you’re on the trickle charger,” Sinclair told Insider. “That’s the physics of electricity.”

The study says isolating the Highland 1103 circuit to run strictly on solar and batteries would cost 2.5 to 3.5 times more in 2030 than the LG&E system. | Courtesy LG&E

Sinclair said the study was unrelated to the renewables resolution before the committee. “Here, we’re focused on just these two technologies because everybody says the secret to the intermittency of renewables is storage. OK, we’re going to look at that,” he said. “We’re not advocating this, this is a thought exercise and we’re trying to identify issues to think about.”

Even if all the homes and businesses installed rooftop solar systems and batteries, the vast bulk of the power would still need to come from big utility scale solar farms, the study shows.

This article has been updated with additional details.