Baltimore County Executive Johnny Olszewski Jr. announced a five-year deadline Wednesday to transition county government operations entirely to renewable energy sources.

To help meet that goal, Baltimore County has hired Silicon Valley-based SunPower Corp. to install solar panels at two landfills, the county’s first large-scale solar projects. The energy produced by the solar arrays — expected to power 35% of the county’s energy needs — is part of Olszewski’s push to invest in more environmental sustainability initiatives.

“Climate change poses one of the most significant threats to our long-term health and prosperity,” Olszewski said in a statement.

The solar project marks a “step forward to ensure Baltimore County remains a statewide leader in renewable energy,” he said.

The county will pay no upfront cost for the solar panels, per a power purchase agreement that stipulates SunPower will finance, install and maintain the solar farms and sell the power to the county. The county would get renewable energy and the developer would get financial benefits, such as tax credits and income from the sale of electricity.

The county will pay $1 per kilowatt-hour for the solar power over the next 25 years, lower than a standard rate from Baltimore Gas & Electric. The county expects the solar projects will generate 43 million kilowatt-hours annually; enough to power more than 5,500 homes.

Olszewski said the savings, estimated in the millions by the end of the 25-year contract, can be redirected “into our communities.”

The ground-mounted solar farms are planned for landfills in Woodstock and Parkton, both closed in the 1980s, according to the Maryland Department of the Environment. Construction is expected to begin in 2022.

In a statement, SunPower executive Eric Potts lauded the county for turning “under-utilized land into productive solar parks.”

During his 2018 campaign, Olszewski, a Democrat, pledged to create a timeline for county government to get 100% of its energy from renewable sources, which will power all office buildings, pumping stations and streetlights, county spokesman Sean Naron said.

Last year the county entered an agreement with Energy Power Partners in June to convert methane gas produced by decomposing landfill waste into electricity.

Olszewski’s administration first put out a bid for a solar energy development contractor in 2019, following one announced in 2016 by the late County Executive Kevin Kamenetz that would have installed solar panels at four county sites. That project fell through.

In 2016, Kamenetz set a goal to generate at least 20% of the county’s electric demand from renewable energy sources by 2022. Between the county’s methane program and solar farms, Baltimore County is now expected to exceed the 20% goal by that deadline.

Josh Tulkin, director of the Maryland Sierra Club, called the county’s 100% renewable energy goal in five years ambitious — but “the fact that they are taking concrete steps on the same day they announced the goal is a good sign ... that that they are on the right track.”

Tulkin questioned the county’s inclusion of methane capture toward its goal. Converting methane to energy still emits planet-warming gases, but less so.

“It is literally burning a fossil fuel,” he said. Still, he added, “I would not look at their policy on [methane capture] and conclude that it means they’re not committed to clean energy.”

The methane capture generators prevent the equivalent of 10,400 tons of carbon dioxide emissions each year, according to the county.

Solar power installation in Baltimore County has been controversial. Rural county communities have railed against proposed solar farms in the past, saying such projects eat up green space and reduce home values.

The County Council approved legislation in 2017 regulating solar development, but allowing projects to be built in farmland. The planning board later recommended the facilities should not be put on productive farmland, and should instead be directed toward business and manufacturing areas.

“We really think this is a win-win situation for people like us who support renewable energy but who would like to see it on the places that, you know, have the most benefits and the least drawbacks,” said Teresa Moore, executive director of the Valleys Planning Council.

The Valleys Planning Council is one of several groups that have challenged building solar projects on vacant land that could be farmed or preserved. Moore advocates for the construction of solar panels on brownfields and buildings.

The Parkton and Woodstock landfills were identified in a list of “optimal sites” which the planning council says would be the most appropriate for the solar projects.

Baltimore Sun reporter Alison Knezevich contributed to this article.