CHICAGO (WLS) — It’s an audacious effort by the city of Chicago to pay for hundreds of of megawatts of clean energy to offset power usage in the airports and every firehouse, police district, library and city-owned building.

The I-Team tracked Chicago energy usage with an exclusive look inside the clean energy compound.

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On a swath of land about three-and-a-half hours southwest of downtown Chicago, on what was once soybean fields, sits a farm of a different kind: 1.6 million solar panels sprouting up, now helping to power the city.

Considered the largest solar park east of the Mississippi, Double Black Diamond’s nearly 4,000 acres straddles both Sangamon and Morgan counties in central Illinois.

Swift Current Energy, which owns the solar farm, said the nearly 600 megawatt power plant has the capacity to energize 100,000 homes.

“When you have places like the city of Chicago, Cook County, Loyola University, willing to invest in renewables and help make projects like this happen, it is going to go a long way towards producing pollution free green power,” said Doug Zeigler, senior director of asset management for Swift Current Energy.

According to city officials, the solar farm supplies 70% of Chicago’s 411 municipal buildings with electricity – including O’Hare, Midway and the Jardine Water Purification Plant.

“We wanted to leverage our buying power so that we could help to support the green economy,” said Chicago Chief Sustainability Officer & Environment Commissioner Angela Tovar. “We wanted to make sure that we were supporting a new solar farm. We wanted to make sure that we were supporting a solar farm right here in Illinois.”

Tovar said the city gets the remaining 30% of its energy through renewable energy credits from a power agreement with Constellation Energy.

The focus on renewables comes as the cost of natural gas and electricity usage for the city has skyrocketed.

The I-Team obtained and analyzed city energy costs over the past seven years, showing from 2017 to 2024 the city used 14% less natural gas, but costs went up 19%. Electricity use increased by 11% in that time, but the cost went up a whopping 80%.

“It’s market pressures. And then it’s also, you know, the increased rate hikes with People’s Gas, too,” said Tovar.

The city has invested $422 million for 100% clean electric power over the next five years. That’s $84.4 million per year. Last year, Chicago paid $91.7 million for electricity.

“It’s a better deal because it is a fixed price, which is the value of a power purchase agreement, is that you get a fixed price over a certain amount of time,” Tovar said. “And so that will work in our favor in the long term, especially as you think about the volatility of the energy markets.”

How does solar energy eventually end up in Chicago?

The solar panels collect the sunlight.

“That sunlight is converted into electrical energy on these panels,” explained Zeigler. “They feed into our substation, which is then ready for the highway of the transmission lines and getting it to the city.”

Essentially, the city is paying for the solar farm to produce enough clean energy for the Illinois power grid to offset the energy used by all city buildings and facilities.

Swift Energy is making a massive investment in the state: $800 million to stand up the solar farm in central Illinois and to make it as efficient as possible, the panels tilt on an axis following the sun in the sky.

“Solar is among the cheapest power that you can build and produce,” said Zeigler.

In 2022, Chicago pledged to reduce its carbon emissions 62% by 2040. Tovar says this clean energy contract is a big step toward that goal.

“Just through this action, the city of Chicago is reducing our carbon footprint by 290,000 metric tons. That is the equivalent of taking 62,000 cars off the road every single year,” said Tovar.

“You don’t smell any smog. You don’t smell any pollution. This is what the state of Illinois could be. And I think it’s on the runway to do so,” Zeigler said.

The city of Chicago is now claiming 100% renewable electrical energy usage for its buildings and facilities and said it is exploring other options to increase renewable energy usage including thermal energy for heat.