Brighter Days Solar Farm

Down the rows

In words: a pale blue sky with a small white sun straight overhead. Three rows of dark blue solar panels on tall grey posts, tilted, each with a bright white line of sun along its top edge. Under each row the soil is in shade. Under the first row, bushy chiltepin plants hung with small red peppers; under the second, jalapeño plants with long green peppers; under the third, cherry tomatoes in cages and low clumps of basil. Two sheep graze in the sun between the rows, and at the end there is a small pale battery shed.

Why the peppers like it

Grow two kinds of pepper under the same panels and they answer the shade two different ways. That is what Star Stuff’s Two Peppers is about, a zine of ours, built from a field experiment outside Tucson where three crops were grown under panels and in the open beside them and measured. The point it ends on is not about peppers at all:

Shade tolerance is not a property of the plant. It is a property of the plant and the place, and it changes when the place does.

So the farm does not ask which crops are suited to shade. It asks how much shade each one wants, and sets the panels for that:

There is no unsuitable crop. There is a ratio nobody adjusted.

The panels over the crops in that field ran about 8.9 degrees Celsius cooler in daylight than panels over bare ground, and the soil under them stayed wetter. From Barron-Gafford and others, Nature Sustainability, 2019; the whole citation is in the liner notes.

What grows under the panels

• Chiltepin peppers

  In the field under panels outside Tucson, chiltepin made three times the fruit it made in the open, and took up a third more carbon.

  Goes to the café in the old dairy, and the honesty box.

  From Barron-Gafford and others, Nature Sustainability, 2019.

• Jalapeños

  Under the same panels, jalapeños made about as much fruit as in the open, with 65 per cent less transpirational water loss. The watering was the same; the plants lost less of it.

  Goes to the café in the old dairy, and the honesty box.

  From Barron-Gafford and others, Nature Sustainability, 2019.

• Cherry tomatoes

  Cherry tomatoes made twice the fruit under the panels that they made in the open. In a greenhouse in Michigan, short of light rather than of water, shading cost them fruit instead: what is scarce decides it.

  Goes to the café in the old dairy, and the honesty box.

  From Two Peppers, Stimpunks Zine No. 87.

• Basil

  Basil stops using more light past a point well below full sun, so the light the panel takes is light the basil had no use for.

  Goes to the café in the old dairy.

  From Two Peppers, Stimpunks Zine No. 87.

Who else is under the panels

The sheep come from the farm next door, to graze between the rows and under them, which keeps the grass down with nobody mowing. Along the ends of the rows there are strips of native flowers for the bees, because a field of panels can be somewhere for them too. The word for all of it is the government’s:

This practice, also known as agrivoltaics or dual-use solar, involves locating agricultural production, such as crops, livestock, or pollinator habitats, underneath solar panels or between rows of solar panels.

And where flowers were planted among the panels at solar farms in Minnesota and watched for five years, the insects came, the native bees most of all:

We found increases over time for all habitat and biodiversity metrics: floral rank, flowering plant species richness, insect group diversity, native bee abundance, and total insect abundance, with the most noticeable temporal increases in native bee abundance.

The nearest real farm like this one is Jack’s Solar Garden, in Boulder County, Colorado, where vegetables are grown under the panels of a community solar garden and researchers come to measure them. Some of the films on the rack below were made there.

The power

Everything on this land runs off the sun, and so does much of the street. Every place out here keeps its own panels and its own battery too, so the farm is a big share of the power and never the only one. This is not a far-off idea for us. It started at home:

In January of 2020, before COVID lockdown, we (a Stimpunks family) signed on a solar plus battery system for our home.