Mosaiko

Solar Panels Versus Trees

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Americans love their trees. As a growing number of homeowners in leafy neighborhoods install solar panels, however, an awkward debate has emerged.

What is more important for the environment and for humans in the long run: clean energy or trees?

As the United States continues to develop renewable power sources and encourage homeowners to take advantage of solar and wind power tax credits, clean energy advocates increasingly run into opposition from environmental groups with other priorities. It can force communities to make tough choices.

In the Washington suburb of Takoma Park, Maryland, city leaders told a homeowner that a tall silver maple tree that would shade the solar panels he planned to install was protected by the city’s strict tree-protection rules. Because the tree trunk measured more than 24 inches (60 centimeters) it was part of the city’s coveted “urban forest,” which covers more than half the town.

In Sunnyvale, California, the solar panels won out. A couple in that community took its dispute all the way to federal court, but they were told they had to chop down two trees that shaded their neighbor’s solar panels.

Under California’s Solar Shade Control Act, homeowners cannot let trees in their yard shade more than 10 percent of a neighbor’s solar panels between 10 a.m. and 2 p.m., when sunshine is most intense.

A homeowner in Winter Springs, Florida, spent $26,000 on her solar panels, crossing her fingers that the city would let her cut down a number of trees that blocked her investment. The city did, but only if she planted new trees where the old ones had stood or paid $250 per tree to have it planted somewhere else.

“We were trying to do what’s right for the environment,” the surprised homeowner told a local television station. “We thought everybody would give us the thumbs-up for it.”

Such debates are mirrored in other parts of the world. In Sweden, for example, groups have protested against construction of large wind-power turbines in what they say are environmentally sensitive areas. In Brazil and some other Latin American countries, hydroelectric projects sparked opposition from people who say the damming of water threatens sensitive ecosystems and native communities.

PROS AND CONS

When weighing trees against solar panels, the decision may depend on where you live, said Pieter Stroeve, a professor at the University of California-Davis and co-director of the California Solar Energy Collaborative.

“In states where there is less sunlight, [sacrificing trees] may not make sense because the return on saving energy from not burning [fossil fuels] may be too small,” he said. In the sunny Southwest, removing trees and replacing them with low trees that don’t interfere with photovoltaic systems may make sense.

Another solar expert and colleague of Stroeve’s, Jan Kleissl of the University of California-San Diego, said many people forget that when trees die and rot, they release the carbon that they once captured.

“Generally the public overrates the carbon dioxide impact of trees,” said Kleissl, also a co-director of the California Solar Energy Collaborative. “Solar panels remove carbon for good by displacing fossil fuels. Solar panels are also 10 to 20 percent more efficient than a tree in removing carbon.”

Removing a large tree for one solar panel would be a waste, but most people have a solar array that is equal to, or larger, than the tree, he said. “And then the solar panels always win.”

TREES COOL HOMES, PREVENT RUNOFF

The Takoma Park homeowner, high school environmental science teacher Patrick Earle, had done the math. He told city leaders that it would take his silver maple tree 140 years to sequester the carbon dioxide emissions that his solar system offsets in one single year.

Half the electricity his household used to buy from a regional power company was generated by coal-burning plants, he said.

“Coal mining in my wife’s home state of West Virginia has disastrous environmental and social consequences,” Earle told city leaders during a recent debate about the city’s tree rules. “Forests are leveled. Mountain tops are completely removed, leaving grotesque scars in the landscape. Rivers are polluted by sediment and acid drainage from mining. Lives are lost in mining accidents. We realized that through our dependency on coal, we were indirectly contributing to all these problems.”

To Earle, it’s a matter of environmental justice as much as reducing greenhouse gases.

“When we are so focused on protecting the trees in our backyards, we lose sight of the fact that in doing so we force other communities to bear the environmental costs of our energy production,” he told America.gov.

The silver maple did come down in the end, but only after Earle agreed to plant 23 other trees throughout the city. He was able to whittle down that requirement to 15 trees after purchasing larger seedlings than originally planned.