Northwest Ohio community saves land space by siting solar project on reservoir

It’s only Wednesday, and it’s already been a week of wild weather that won’t soon be forgotten in Ohio. Intense thunderstorms have reached every corner of the state, and strong winds flipped over a car on the interstate north of Columbus. Heavy rainfall put many counties under flood watches, and central-Ohio utility AEP Ohio said it would still take a few days to bring the 135,000 customers who lost power back online.

One community in Northwest Ohio braved the continuing rain to celebrate the completion of a solar project that thrives in water. A 2-MW floating PV array was recently finished atop the Twin Lake Reservoir in Lima, the third floating solar project in the state, all developed by D3Energy and constructed by ARP Solar. The companies completed a 1.5-MW array for Del-Co Water in the city of Delaware in 2024, and a 6-MW system in Monroeville will come online before the end of the year.

The Twin Lake Reservoir is the primary drinking water source for Lima’s 35,000 residents, and the water treatment plant next door processes 14 million gallons each day. By far the city’s largest energy consumer, the water treatment plant will benefit from the solar project that is expected to provide $10 million in electricity savings over its lifetime.

“This project allows us to take an asset we already have — our reservoir — and use it in a new way to support the critical work happening at our water treatment plant every day,” said Michael Caprella, Lima utilities director. “When you are treating approximately 14 million gallons of water each day, energy efficiency matters. This array gives us another tool to manage those costs while continuing to provide the safe reliable water our customers depend on.”

The state-wide rainfall has no affect on the floating solar project, as the system’s mooring lines and anchors adjust to fluctuating water levels. Over 3,100 bifacial solar panels are mounted to Ciel & Terre Hydrelio floating systems and anchored to the reservoir’s banks and bottom. Power is fed to eight Yaskawa Solectria XGI inverters on the shore.

The 2-MW project sits on only four acres of the reservoir, whereas a project of the same output mounted on land would need at least 10 acres for appropriate spacing. For a state that has sometimes been hostile to solar projects on land, no one in Ohio seemed opposed to this floating solar project, said Stetson Tchividjian, D3Energy managing director.

“This project shows that clean energy doesn’t have to come at the cost of land,” he said. “By building on water the city already owns, Lima is generating 2 MW of clean power while preserving nearly 10 acres. That’s why D3Energy exists — to help communities grow their energy independence without giving up their land.”

The completion of the Twin Lake floating solar project represents years of collaboration spanning multiple mayoral administrations and partnerships at the local, state and federal levels. Planning began five years ago, and Lima city council authorized the project in 2023. The $5 million solar array secured $2.4 million in grants from the U.S. Dept. of Energy, which former state Sen. Sherrod Brown helped secure, and it will take advantage of nearly $1 million in direct pay tax credits.

“This project is a great example of what can happen when leadership carries forward across administrations, and organizations come together around a shared goal,” said Lima Mayor Sharetta Smith. “Today, we aren’t celebrating one person or one moment. We’re celebrating the many people who believed in this project, helped move it forward and ultimately brought it across the finish line.”