Woodbury man harnesses the sun

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Forty years ago, Woodbury resident Kerry Smith wanted to get a degree in solar engineering.

But there was no such thing.

Now the technology has grown so much that the federal government and energy companies encourage homeowners to use renewable energy.

And that’s just what Smith did: he took advantage of federal tax credits and Xcel Energy rebates last year to install 11 solar panels right in his backyard.

The front exterior of his Watertower Place home is just like any other in the neighborhood. But the back houses a tracker system that follows the sun at different times of day to power the house.

“Tracking is about 40 or 50 percent more efficient than a fixed panel,” he said.

Smith’s residence was part of this year’s Minnesota Renewable Energy Society Solar Tour Saturday, Oct. 6. His “Doc Smith Labs PV System” was the only Woodbury home in the tour that featured 75 systems.

Before deciding on the best place to install the solar panels, Smith said he thought about installing the standard rooftop system.

But because of the direction of the sun, it would’ve had to be visible from the front of the house and he didn’t want it to interfere with the look of the home.

So he looked into the tracker system that has to fit into 200 square feet of space with limitations on how far it had to be from neighboring homes.

About two months later and 10 tons of concrete, the “over-engineered” system was installed, Smith said.

The panels face east when the sun rises and follow the direction of the sun until about 4 p.m. when it starts moving fast to get back around and prepare for the next day.

There are black boxes behind each panel that convert the DC (direct current) output of the module to AC (alternating current).

The AC from there then runs to the house where it goes to a production meter so the utility company can track the “green energy” requirements they must meet, then it connects to the house’s main breaker panel, Smith said.

Although at first he wasn’t serious about the panels and the entire system that can provide up to 4,400 kilowatt hours, assuming no shading, he ended up with a large structure in his backyard.

“I just wanted to get something to play with so I was going to get one or two,” Smith said. “The recent price drop of PV modules convinced me this was a good time to join the revolution.”

The rebates and tax benefits that came with it were appealing enough to install the 11 panels, too.

But the tracker was only available in nine and 12 panels, and city code would only allow for nine based on the space he had available. Smith wanted to get as much out of the system as possible, so he installed two more fixed panels on the ground.

Sometimes he gets a check from Xcel for the difference in energy that makes the meter actually run backward.

“The electricity flows both ways,” Smith said, adding that it’s always fun to see the meter go the other way for a change. “All that extra power runs back to Xcel.”

Xcel capped the credits to 40 percent of homeowners’ usage, Smith said, when so many solar panel owners started getting a lot more credits than the company wished to give out.

Smith figured the amount of electricity the solar panels produce is about one-third of his total usage.

“And that equates to about $60 a month,” he added.

Being a retired electrical engineer, Smith likes to do the math – it’s about a 5 percent return on investment.

And he gets a tax break, too.

“It’s not like a stock or a bond, there is no risk in this,” he said. “I know where my investment is, it’s in my backyard.”

Over the months of August and September, Smith’s system was producing as close to maximum output as possible with a lot of sunny days and hardly any cloud coverage.

“I’m real happy with what we got out of the system,” he said.

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