Butterflies, blue-greens, kilowatts, and calories

Sheep, perennial plants, and solar panels could help solve water problems, with the right design and locations. (Photo by Photo by Merrill Smith, U.S. Department of Energy)

Solar energy is helping move the world’s energy production from fossil fuels to carbon-free sources. Done right, it could also offer a solution to other serious environmental problems.

Not only is the planet’s climate warming quickly, but much of Earth’s water is contaminated with nutrients, harmful algae, and chemicals that make it unsafe to drink. A million species of life are at risk of extinction, including creatures like pollinating insects that are critical to human survival.

The best ways to solve these problems are still up for debate — no matter what, big challenges will require big changes. Any strategy that can help address all these issues at once means saving valuable time and resources.

New research points to the potential of “farming electrons” to do exactly that.

Solar panels take energy from the sun and turn it into endless electricity, without adding carbon to the atmosphere. The technology provided more than 1 percent of Minnesota’s electricity needs in 2018, a 50-fold increase from 0.02 percent in 2015. Xcel Energy recently announced it expects to more than triple its solar generating capacity in the state by 2030.

But a solar farm can grow more than one crop, according to Dr. Shawn Schottler of the St. Croix Watershed Research Station and his colleagues. It can also reduce runoff into lakes and rivers, provide habitat for bees, birds, and butterflies, and produce meat for human consumption.

It can do all this while producing revenue to support farmers and rural communities.

To maximize the benefits of solar farm, they must be located in the right places with perennial vegetation planted underneath them.

Until now, the potential benefits to water quality of combining solar and vegetation has not been seriously studied. Schottler’s analysis shows that solar installations could be another way to reduce the overall costs to taxpayers or farmers while making significant strides in improving Minnesota’s clean water.

Schottler’s study builds on previous research that shows much more perennial vegetation is needed on Minnesota’s landscape to make meaningful improvements in water pollution caused by runoff. Novel strategies will be necessary to meet the state’s water quality goals.

Combining solar, perennial plants, and sheep on a regular rotation could help meet essential needs like food, water, and energy, all on the same acres of land. Providing resources humans need in the century ahead, while protecting air, water, wildlife, and climate, is a balancing act that is constantly becoming more critical

The results are still preliminary, but the analysis identified potential benefits of solar that go far beyond energy production.

An acre of solar panels can provide 20 times the energy produced from an acre of corn grown for ethanol, plus pollinator habitat, and nearly as much meat. Three million acres of cropland in Minnesota are used for ethanol and byproducts.

Right now, about 25 percent of America’s corn acres is used to make ethanol and other biofuels, excluding byproducts used for livestock feed. That is in large part because the federal government currently requires American consumers to use about 14 billion gallons of ethanol – approximately 10 percent of gasoline – in order to create a strong and stable market for corn.

But there are other ways to produce energy and protein on the land. Trading corn and cattle for photovoltaic cells and sheep could have an oversized impact.

Schottler’s analysis found that an acre of land with solar panels on it can make at least 20 times as much energy as the same acre growing corn for ethanol, and almost as much meat. Sheep provide nearly as much protein per acre as cattle, and fit under the panels, don’t chew on wiring like goats, and don’t require wintering like cows.

There has been some recent buzz about planting pollinator-friendly vegetation at solar farms. In 2016, agriculture, energy, and environmental groups in Minnesota worked to establish the nation’s first statewide standard for vegetation on solar sites. The initiative pointed to the potential of generating energy and providing pollinator habitat on the same land.

“Because the United States solar industry first took off in the desert Southwest, a standard practice for the land on solar sites is gravel and/or shallow-rooted lawn grass,” says Fresh Energy’s Center for Pollinators in Energy.

A key principle to getting water-quality benefits from the solar-perennials-sheep strategy is to locate some solar sites in sensitive areas where they can reduce the most runoff. Solar sites installed on lands adjacent to streams, and the required streamside buffers, could have a significant positive impact on water, while helping offset the costs of prohibiting annual crops in buffer areas.

If solar farms are installed in sensitive areas, energy development could reduce not only greenhouse gasses, but drive improvements to water and wildlife.

Because solar is such an efficient way to generate energy, we won’t need that many acres of it in Minnesota, it will be critical to provide financial or administrative incentives if we want solar farms in areas that also provide water quality benefits.

Harvesting electricity

Pollinator-friendly solar could also benefit clean water. (Photo courtesy Fresh Energy)

Schottler’s research, funded by the Minnesota Environment and Natural Resources Trust Fund on the recommendation of the Legislative-Citizen Commission on Minnesota Resources, has analyzed numerous scenarios to reduce runoff with market strategies.

Progress on the state’s water quality goals has been slow and improvements remain distant because the amount of land covered in perennial vegetation has remained low. Most protection efforts have focused on small-scale projects to slow runoff, capture sediment and nutrients, and restore wetlands. The benefits of those efforts have too often been overwhelmed by the intensification and expansion of agriculture elsewhere.

So, much of the water in southwestern Minnesota remains in about the same poor condition as it was 25 years ago — overwhelmed with algae, toxins, sediment, and flooding.

Planting sensitive lands with vegetation that reduces contaminant runoff — and produces energy and food — has the potential to finally cause the large-scale change needed to make measurable improvements in clean water.

With prices plummeting and demand soaring, solar projects are coming to America in a major way in the near future. Solar energy development will never exceed more than one percent of America’s 990 million acres of farm and range land, but can be an important part of the solution to providing a clean water supply for the next generation. Now is when the public can actively shape how different solar development designs could result in additional benefits.

Metaphorically, the country is at a policy knick point — the unstable place where a prairie stream cuts through a bluff and down to a river below. Putting solar farms, perennials, and sheep in sensitive areas can help form a firm channel that lets the water flow but reduces what it washes away.

2019 Agroecology Summit

Friday, August 16th, the Willow Lake Farm will warmly welcome visitors for a weekend of conversations, swimming, camping, field trips, homegrown food and live music.

August 16-17, 2019
Willow Lake Farm
Windom, Minnesota

How do we find a path to cleaner water and better habitat while maintaining agricultural profitability? What will it cost and how can we pay for it?

To help answer these questions, we will present tangible examples of policies that could improve water quality and habitat by creating incentivized markets for products derived from novel, perennial cropping systems.

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