Students try to make solar power viable

Cincinnati Business Courier ^ | December 13, 2002 | Laura Williams-Tracy

[Willie Green]

For education and discussion only. Not for commercial use.

Apathy, expensive equipment among hurdles

Solar energy has become almost a throwback term from the energy crunch of almost three decades ago, when some environmental advocates felt homeowners could help end the country's reliance on imported oil and reduce pollution.

Unattractive solar panels on rooftops popped up here and there, but generally the technology failed to catch on in any great numbers with homeowners.

But some architecture students at the University of North Carolina-Charlotte proved recently that with the right technology, the sun can satisfy much of the power needs of today's energy-hungry homes.

Under the direction of Dale Brentrup, a professor of architecture at UNC Charlotte and director of the lighting and energy technology lab, a team of 15 students worked over three school terms to demonstrate the viability of solar power. The UNCC team designed a solar-powered house, raised money and material donations for its construction, and built the structure in time to compete in the U.S. Department of Energy's Solar Decathlon, held recently in Washington, D.C.

UNC Charlotte was one of 14 schools competing for the top prize, which was awarded to the team that could build the most energy-efficient solar home.

During three weeks spent operating their houses on the Mall, students were charged with proving to judges that their projects could meet high-energy demand. Students were required to use solar energy to cook their meals — including breakfast for the judges — power a computer to generate a newsletter, power and drive a solar car and run a television for eight hours a day.

"We had to assure everyone this was a real house," said Brentrup.

And based on the cost — close to $130,000 — the house was no feeble attempt at demonstrating the virtues of solar power. Donations came from companies such as Insulspan and the N.C. Modular Home Institute for structural elements; Velux and MW Manufacturers Inc. for windows and skylights; and ASE Americas Inc. for the home's 16 rooftop solar panels. Those materials were supplemented by significant funding from the university, allowing the students to compete with a sophisticated model home.

The university finished the competition near the bottom of the pack, but Brentrup said the experience was enlightening for students, and the house is back on campus for use as an education tool.

"Currently there is a large push for a resurgence of these issues connected to sustainable design," said Brentrup. But, he said, overcoming the inertia that has marked the public's attitudes toward alternative energy has been challenging.

In part, that's been because solar energy, while unmetered and renewable, is certainly not free. As with any energy source, it requires equipment to collect, store and distribute power. And that technology is far more expensive than traditional power grid technology. Brentrup said some competing schools spent as much as $400,000 on their solar homes.

The cost-benefit analysis makes solar power the most viable for homes in remote locations that would require large costs to install electric lines.

That's been the experience of Jason Grant, general manager of Express Plumbing, Heating and Cooling in Charlotte, which recently installed a $45,000 solar system in a remote mountain cabin. The system was far less expensive than the more than $100,000 that would have been required to extend power lines.

State-of-the-art solar systems for homes start at $30,000, and Grant said that cost largely explains why homeowners have been reluctant to go solar.

"With a $100-a-month light bill, it takes quite some time to recoup your $30,000 investment," said Grant.

But he said those who choose solar energy even when less-expensive options are available do so for personal reasons.

"Your motivation has to be political or to make an environmental statement or be in a remote location, otherwise it's not feasible unless you have won the lottery."

The market isn't limited to the environmentally obsessed or mountain hermits. Solar water heaters have become more common because they will pay for themselves in tax credits and energy savings within five years. And solar power is popular for secondary lighting systems, such as landscape and emergency lighting.

Mark Baldwin, executive vice president of the Charlotte Home Builders Association, said with traditional energy sources so abundant and affordable, few builders or homeowners have opted for solar technology in area homes.

"After the OPEC energy crunch of the 1970s, solar was huge," said Baldwin. "But I haven't heard anyone mention solar in years."

In some states, such as Virginia, Wisconsin and California, the growth of solar energy for residential and commercial use is coming in the form of an arrangement called net metering, said Brentrup. In cooperation with local power companies, homes and offices with solar technologies are also connected to the region's power grid.

For homes, during daytime hours when families are away at work and school, solar energy is used to power the few appliances in use, such as the refrigerator, while the rest of the solar energy being collected is turned back to the power grid for credit.

In the evenings and mornings when the family is home and more energy is needed to power kitchen equipment, showers and televisions, the home draws its energy needs from the power grid. This "net metering" practice reduces use of power from traditional electric sources.

While no power companies in North Carolina offer net metering, Brentrup said the state offers some of the best rebates for renewable energy in the country in the form of tax credits to owners of solar panels, solar water heaters and other renewable energy technologies.

[Cicero]

I'd be delighted to install solar power if it were affordable. Our power company's rates are among the highest in the country. But it still isn't practical.

[Chairman Fred]

There's nothing more useless in a blizzard than a solar heating system.

[dogbyte12]

A man I know here in Southern California actually does run everything on solar, and quite well. It will take a while to pay off, he did it more as a vanity project. He actually does end up selling power back to the energy company more power than he uses, but the cost will take a good 15 years to even out.

If you live in a sunny environment and have the money, and are young, it isn't a bad investment in that regard. Getting checks from the power company every month that are actually profit, will come in hand nicely for retirement. I wouldn't recommend it now though, for anybody over 45 or 50 with the current state of technology.

[templar]

But it still isn't practical.

The practicality depends more on the storage system than on the collection system. although both are important. Harnesing the suns energy in an electric battery system and hot water is dependant on fairly high tech collection as well as expensive storage components, which is why it is so expensive.

Fortunately, there is existing technology that can collect and store solar energy quite affordably and provide both heat and electricity at a price almost anyone can afford to install in their home. This can also be used both on grid and off grid, depending on the practicality of transmitting from a central location (population density). There just doesn't seem to be much commercial incentive to use these systems, which is why most of the ones in use are, basically, home engineered by experimenters and tinkerers.

[BIGZ]

The Government Screwed up the the Solar Tax Credit program in the 80s by not understanding the ingenuity and resoursefulness of the American people. Instead of putting a cap on a graduated scale on the total cost of the system the government issued a 50% tax credit and the result was the tax credit was being sold not the Solar System. In some cases a 50% tax credit coupled with a 15% investment credit and accelerated depreciation you could get a tax shelter of over 100%. The American people figured this out pronto it took the Government years. This is from the same brain surgeons that during a water shortage advised you to restrict you toilet water closet by inserting gallon bottles or bricks in a closet that required 5 gallons to flush. It takes a least 2 gallons to siphon this type device, the result was you had to flush twice using six to seven gallons to eliminate the waste.

They are brilliant!

[BIGZ]

A PS to my prev.

A properly installed Solar System for hot water is not that expensive and it WORKS rather well.

[sonofron]

the trick is to combine solar panels with wind power.

[RLK]

The sun's output is 100 mw under ideal conditions. When the birds crap on your solar cell array or bugs land on it, output goes to squat. Dust is similar. Clouds? Winter sun angles? Leakage current in solar diodes due to heat?

[ASOC]

Gee
Those can be a problem, but if you take a bit of time each day or weekend....you can stay ahead.
I have a small place that is solar (due to high cost power lines) we put on solar with 'salvage" or free panels and batteries purchased from a golf course for "scrap" value.

Not a big thing, but do-able

Have fun

[patton]

OK, give. Where did you land the gear? My cabin is landlocked from Electrons.

[Jhoffa_]

Along these same lines, I once saw a guy with a big frensel lens (I think that's what it was, sort of opaque looking and had grooves in it. Like what you would see in an old overhead projector maybe.) melt concrete..

If you could focus several of those, could you boil enough water with them to run a small steam turbine?

Hey, it melted concrete..

?

[Jhoffa_]

Be even neater if you could capture and condense the steam, recycle it.

Add some type of X-Y positioning device run with stepper motors and phototransistors, or a lookup table for position or something so it could track the sun as it progressed across the sky.

[cmsgop]

Do you write for Radio Shack ?

[steve86]

When the birds crap on your solar cell array or bugs land on it, output goes to squat.

What are you talking about? Even if there were a completely opaque obstruction on part of the glass, panels are partitioned into zones and the other zones are unaffected.

I just cleaned bird stuff off a panel today. There was no measurable effect on output whatsoever. The solar insolation simply refracted under the spot and onto the photovoltaic grid. This was easily apparent looking at the silicon cell from the side. The cleaning is more so humans feel better about it than anything, although I'm sure a big enough bird could cause problems, but then that would cause problems on your windshield too.

Please explain the statement "The sun's output is 100 mw". Seems to me that if the sun can heat up the earth from so far away it must be greater than that.

[Jhoffa_]

LOL!

No, but I own all the Radio Shack, Forrest Mimm's notebooks though..

[RLK]

You'd probably have a good shot at running a small steam turbine or steam engine.

[1redshirt]

I put my panels on the outside of the railing of my deck not on my roof. They get just as much sun and are easily cleaned. I also use mirrors to reflect more light onto the
panels. I don't run the heat, air conditioning, or oven on the panels BUT everything else is run on them. I have a bank of 20 batteries mostly gel type. I get them from fire stations. Fire stations have to recycle their backup batteries EVERY year whether they are good or not. I pay between $10-$30 dollars each for them. The batteries can run all I mentioned for 3 days with solar assist. Hooking a windmill to the system would be a piece of cake. I am going to do just that in the spring.

[1redshirt]

BTW I only have 2 110 Watt panels

[RLK]

In the 70s I was part of a research team working on solar cells. 100 mw is what you get. To see the effect of dust and bird crap you need to measure the internal resistance of the cell under various conditions. For some things solae cells will work decently. Just remember something like a small air conditioner will draw in the order of 12 amps at 110 volts. That's a pile of solar cells.