Clean Energy: Rooftop Photovoltaic Power Plant

Wednesday, February 11th, 2015

I own a power plant: my roof sprouts an array of photovoltaic panels that convert solar energy into electricity for my house and garage/studio. What I don't use (which turns out to be a bit under half of what I produce each month), feeds into the electric grid.

My power plant, producing electricity even in a summer hailstorm. My power plant, producing electricity even in a summer hailstorm.

Unlike conventional coal and gas-fired power plants, my small photovoltaic "plant" doesn't produce unhealthy emissions or add CO2 or other more destructive greenhouse gases to the atmosphere. (Manufacturing the panels does create a "carbon cost," however.)

The panels work quietly and simply: Sunlight hitting a layer of silicon crystals causes them to shed electrons. Those electrons flow into wires connected to each panel, and voilá, it's power.

Of course, as I wrote several years ago in an article for Audubon Magazine, "This lovely green power is direct current. Therefore it can’t make your Cuisinart hum until an inverter... makes it into alternating current." Each of my panels sports a mini-inverter right on the rooftop.

My power plant is clean and efficient and my two small buildings were designed to sip energy instead of gulping it, drawing on the sun's heat in winter instead of a furnace and down-valley breezes in summer instead of air conditioning.

My twin power meters--the one on the left measures what I produce, the other what I consume. My twin power meters--the one on the left measures what I produce, the other what I consume.

Which is why my electric bills total in the negative numbers, and the power company pays me for the excess I generate instead of me paying them.

Solar panels only produce electricity when the sun is above the horizon (though they do generate even when it is cloudy or snow blankets the panels). So I draw on the power grid at night; but peak power consumption is in the daytime anyway.

There's plenty of solar energy for the harvesting: According to the U.S. Department of Energy, enough solar energy reaches the earth’s surface every minute to meet the world’s energy demands for a year.

In the fifteen months that my power plant has been up and running, I've produced enough spare clean electricity to power an average American household for four months. (When I looked up those data, I was shocked to realize that my use is about a tenth that of the average household. More of us need to conserve, it seems.)

Creek House, my small house, on a clear evening. Those reflective dark panels on the roof are a 3.0 kw photovoltaic array. My 3.0 kw photovoltaic array, still generating a trickle of power even after sunset.

The best part about the power plant on my rooftop? Knowing I'm helping to combat global climate change by generating clean electricity. My system has offset 3 tons of carbon in 15 months, which is equivalent to planting about 75 trees.

I'm no saint, environmental or otherwise. But it truly does feel good to do good.