Solar Double Cropping

Reader Contribution by Lyle Estill
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For as long as I can remember, my brothers and I have been gathering for “Brother’s Weekends.”  There is no schedule, and seldom an agenda, but growing up in a family of four boys, we have simply gathered together at random intervals to connect, and laugh, and discuss our individual lives together.

On one such occasion we met in Lion’s Head, Ontario, on the edge of Georgian Bay.  I was walking down Isthmus Bay road with my brothers Glen and Jim, and we were discussing a new law proposed by the government of Ontario that would ban all new solar installations on farmland.

Earlier they had passed a lucrative feed-in tariff that made the creation of solar electricity extremely attractive.  Solar became the most profitable thing you could do with land. People were bulldozing vineyards to put up solar farms, and the government decided that was not what they intended.

We walked toward White Bluff and discussed the classic “food versus fuel” debate. I’m in the biodiesel business, where we turn fat into fuel, so that is a topic that is close to my heart. 

My brother Glen envisioned elevated solar panels with crops growing beneath them.  He is in the wind business, where the notion of “double cropping” is commonplace. 

Whenever you see a picture of a giant wind turbine, you typically see a bunch of happy cows grazing below.

I returned from the weekend with the idea lodged in my brain. I work at Piedmont Biofuels, which makes fuel out of used cooking oil from local restaurants, and our plant is surrounded by Piedmont Biofarm—a sustainable farming operation with three acres of produce under cultivation.

Piedmont Biofarm is the domain of Doug Jones, an award winning farmer with an eye toward innovation and sustainability.  When I ran the idea past Doug he pointed out that our agricultural zone is changing—we are becoming increasingly hot, and increasingly arid in the piedmont of North Carolina.  As a result, many of our regular crops are migrating northward.  He felt that perhaps his agricultural production could benefit from a little shade.

Encouraged by his enthusiasm for the idea, we built a cold frame using a partial-shade solar panel.  In the prototype, 50% of the light energy would be converted to electricity, and 50% would be available for vegetable growth.

It worked like a charm.

Solar generation in North Carolina comes about through the tax code.  As a regulated market that favors subsidized coal and natural gas, solar will never compete for the production of electrons.  But for those with a tax liability, solar becomes an excellent investment. 

In the absence of my own tax liability (I am in biodiesel, after all), I brought Michael Tiemann into the discussions.  He was just completing his construction of Manifold Recording, which is one of the world’s great recording studios. Apart from being an amazing creation, its existence meant two things:  a new consumer of electricity that would prefer to be offset by “green” electrons, and a substantial tax liability that would benefit from solar tax treatment.

With Glen’s idea, Michael’s tax appetite, Manifold Recording’s desire for green attributes, Piedmont Biofuels’ thirst for electricity, Farmer Doug’s cooperation, and the ingenuity of David Boynton at Southern Energy Management, we managed to build a 97kWh array over the north field of Piedmont Biofarm.

So far it has performed beautifully.  On sunny days it delivers about a half a megawatt of electricity to the biodiesel plant, while providing strategic shade to plants below.  Energy is produced above as farmers harvest below in a genuine double cropping scenario.

While climate change mitigation has been controversial, and “cause and effect” arguments have been politicized, there is not really anything to fight about when it comes to adaptation strategies. 

Solar double cropping is one such strategy.  It creates clean energy to fuel our economy while it augments the production of food.