Juli Burden has spent three years growing crops in the small shaded corner of a 130-acre solar power plant in Mililani.
Lettuce, kalo, sweet potato, vanilla and even māmaki — all grow under solar panels that automatically rotate with the movement of the sun.
Burden is a research assistant with the Hawaiʻi Agriculture Research Center and she wants to know which crops thrive under various levels of shade cast by the panels.
Because the solar panels rotate, the shade they cast differs throughout the day depending on the location of the plants underneath. Plants directly under the panels are in full shade in the daylight, and plants off to the side get partial shade.
“In a lot of ways the system is agroforestry — it's just we have bionic trees that are providing the shade. It's basically not trying to smash a plant or crop in a system that doesn't want to be there but finding what works best,” she said.
The Mililani Agricultural Park houses Clearway Energy Group’s 39-megawatt power plant where Burden works.
Agrivoltaics, co-siting solar panels and agriculture, isn’t a new concept. However, experts say there’s a lot more that can be done locally.
Nicola Park, Clearway’s director for Hawaiʻi, said the group is expanding its agrivoltaic efforts.
“There’s a lot of acreage that we could expand into, but for development projects, on the order of 500 acres of land that we could explore for a variety of these types of agricultural uses,” she said.
Burden is also growing a variety of mushrooms and has a bin for vermiculture under the solar panels.
“Not all sites will lend themselves to crops, but there's a variety of things that we can look at, between contributing to food hubs, beekeeping, pollinator species, a variety of things that we're really excited about trialing,” Park said.
The work has received the attention of local lawmakers. Rep. Nicole Lowen, who chairs the House Committee on Energy and Environmental Protection, and Rep. Amy Perruso, who sits on the Committee on Agriculture and Food Systems, recently visited the site.
Co-siting means both agriculture and renewable energy take advantage of desirable land, but it also means both can share costs to operate, such as rent or utilities.
“The land that is the most desirable for both agriculture and energy projects — and development, for that matter — it's all the same land,” Lowen said. “The idea of being able to combine them together opens up possibilities for being able to use potentially more land that also is more accessible and easier to use, which could lower the cost of projects.”
Burden hopes her work can show local farmers that agrivoltaics is possible. Farmers would have to feel confident in her findings before taking on the financial risk of farming at an operational solar power plant.
But Burden also hopes to show farmers that it’s not just possible, but profitable, too.
“One of the things why I really love about these systems is, you know, potentially you're seeing reduced rents for farmers. Also lowered water costs, potentially by subsidizing some irrigation costs,” she said. “A lot of the goals of this partnership is really to make farming more profitable for farmers.”
Park said there is already interest in farming under Clearway’s solar panels.
