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Agrovoltaics: a solar-powered safety net for Massachusetts farmers

The long-term, steady income of solar power complements the higher revenue, but harder work of traditional farming. The Massachusetts SMART program looks to increase this trend with “agrovoltaic” incentives for solar co-located with crops.

They’re called solar farms for a reason – we deploy our seeds of steel, we water the ground with copper, and we pray to the sun gods for plentiful photons! Our previous coverage has noted the trend toward pollinator friendly solar farms, but this is just the beginning.

A recent story by SouthCoast Today on cranberry bogs in Massachusetts shows the stresses of the farming life as the market value of cranberries falls. In the article, a farmer from Carver shows off a bog that has been fully converted to a standard solar power installation:

The City of Dartmouth, where pv magazine author resides, is now grappling with whether to adjust town ordinance and allow a 30-acre solar farm that makes use of a new technique to co-locate solar power and traditional farming: called agrovoltaics (or agro-photovoltaics).

The new SMART program by Massachusetts incentivizes agrovoltaics to the tune of an additional 6¢/kWh in a 20-year contract (see image below):

In designing the solar power incentives for the next 1.6 GW to be deployed in the state, program designers made it clear that the state didn’t want to destroy our farms and forests for solar power. As noted in the SouthCoast Today article, the 30-acre solar farm system is not the standard ground mount, but is instead located eight to ten feet above the ground. It must also be demonstrated that the solar power system will not lessen sunlight to any farming lands by 50% or more. These and other requirements of design are located in the state’s Definition of Agricultural Solar Tariff Generation Units Guideline (PDF).

Imagine something like this, but probably denser:

One of the world’s largest agrovolatic systems is built in China by Huawei. The system is 1 GW-DC, and utilizes trackers and module level electronics.

As seen in the above Twitter account, Thibault Frisson is a consultant who specifically focuses on integrating the proper crop distributions under various racking structures in agrovoltaic deployments. Frisson cannot do a wind load analysis, but he can make sure your cranberries grow full and strong.

There have been many scientific studies at this point looking to tie together crops and solar power. In research presented by the Fraunhofer Institute for Solar Energy Systems, (the source of this articles header image), we got to see both the cost in crop yield and gain in electricity revenue:

The crop yield of clover grass under the PV array was only 5.3 percent less than the reference plot. The yield losses for potatoes, wheat and celeriac are between 18 to 19 percent and therefore somewhat higher. With an installed power of 194 kilowatts, the photovoltaic array can supply 62 four-person households with electricity. In the first twelve months, the array produced 1266 kilowatt-hours electricity per installed kilowatt, one third more than the average value of 950 kWh/kW in Germany.

The combining of the two resources, while it lowered the output of either compared to a pure installation, was a “160% increase” in a combined agricultural and electricity output. What this 160% number means to individual groups varies of course, as the price of electricity and the crop varies by region – but its clear that its more than either on its own.

This is also an area where bifacial modules are proving their worth.