Dive Brief:

Cincinnati is releasing details about a plan to build what's being touted as the largest municipal solar array in the United States: a 100 megawatt (MW) solar installation about 40 miles east of the city's downtown.

The solar array will cover about 1,000 acres with more than 310,000 solar panels, transitioning up to 30% of the city's power from fossil to renewable fuels, according to Cincinnati Mayor John Cranley​. A 35MW installation to power city buildings is expected to be in service by December 2020, and the 65MW residential portion tentatively should be live by December 2021.

A 35MW installation to power city buildings is expected to be in service by December 2020, and the 65MW residential portion tentatively should be live by December 2021. The city entered a 20-year power purchase agreement so power will be supplied at a fixed cost for the duration of the contract, and the city does not have to pay up-front costs for the solar field construction. "I think we all have a responsibility to do what we can do to deal with our carbon footprint, but we also have to be responsible... stewards of the tax dollar. What we have been able to do by getting economies of scale is bring the price down enough that we're saving money," Mayor Cranley told Smart Cities Dive. "We're very proud to be leading what we believe to be the largest city-led solar project in the country... We think [cities] should look into it both for environmental and also for economic reasons."

Dive Insight:

This solar array project came to light two years ago, just before Cincinnati announced a contract to purchase 100% renewable energy for most municipal facilities. At that time, the city estimated its switch to renewable power at city-owned facilities would cut emissions by more than 9% and save more than $100,000 annually on its utility rates.

Cincinnati should be able to power about 25,000 homes each day with the new solar array once it is completed. The city estimates the renewable energy will reduce the region's carbon emissions by 158,000 tons annually, or the annual equivalent of removing 30,000 cars from the road or planting 2.4 million trees.

Besides the environmental gains, Cranley says there are financial gains from entering the 20-year power purchase agreement. But he cautions cities considering similar deals to do their homework to ensure they receive favorable pricing and don't get ripped off. Building a large enough solar installation is part of what makes the math work, he said.

"The real energy savings comes from the massive array — 100MW to begin with," Cranley said. "It's probably a $40 million project, but once you... get bigger and better, the price comes down." Not every city has the ability to create such a large-scale installation, but they can collaborate with other communities to get the economy of scale and financial benefits, he said.

In addition, the project is considered an economic boon because it will create jobs. Cincinnati State Technical & Community College and the IBEW Local 212 will collaborate on this solar project and put in place a workforce skills and hiring program.

"We see this as the future... To bring jobs to this region is a tremendous win," Dan Sawmiller, the Natural Resources Defense Council's Ohio energy policy director, told Smart Cities Dive.

The solar array is one of numerous steps Cincinnati has taken recently to reduce emissions. This summer it added the first electric vehicles to its city fleet, with intentions to add 20 more and 160 charging stations. Cincinnati was one of the 15 cities to receive financial and technical assistance for its efforts to achieve certification through the LEED for Cities and Communities program. And it was named one of the winners of Bloomberg Philanthropies' American Cities Climate Challenge.

Sawmiller anticipates that like Cincinnati, more cities will take on their own projects to reduce emissions and mitigate the effects of climate change amid waning support from state and federal governments.

"We're seeing leadership from our cities. Cincinnati is stepping up in a big way and making a big commitment. I think the city is geographically in a really interesting location to make this commitment and show the region this is something we can be doing," he said. "This is an example of how you do it, and I expect we'll see more and more of this."