Pueblo, Colo., tour of homes generates interest in solar power

The Pueblo Chieftain, Colo. --Oct. 10

Oct. 10--There were times during last weekend's tour of solar homes when Sallie Watkins felt like she was back in the classroom.

The retired CSU-Pueblo physics professor said she stopped counting after 150 people toured her Pueblo West home, most of them fascinated by what's probably the largest solar-electric system in the county.

One visitor even asked what happens when all the electrons are gone, she said. "I told him, the world has plenty," she said with a laugh.

Even though solar cells have been around since researchers at Bell Labs created the first ones 50 years ago -- and they're increasingly used to power everything from hand-held calculators to landscape lights -- the process remains a mystery to many.

Scientists learned in the early 19th century that light could "excite" atoms in some substances, sending electrons moving from one to another and generating electricity. The first photovoltaic cells -- using light to make electricity -- were developed in 1954 using silicon and while they've become more efficient, the basic design has changed little since then.

Watkins has 14 panels mounted on the hill behind her Pueblo West home that generate up to 4.2 kilowatts of power. The direct current electricity flows into an inverter in her garage that changes what she needs into alternating current and stores the rest in a cabinet containing a dozen batteries.

Any surplus power flows back through a meter outside the house and into Aquila's grid. If at night or when it's cloudy, and the batteries don't have enough juice, power flows back in from Aquila.

Under federal law, Aquila has to reimburse her for the power she sends back into the grid, albeit at the wholesale price while she pays retail when she uses it, but it makes a significant dent in her monthly bill.

In August, for example, she paid only $16.31 to the power company, mainly to cover the overhead costs of having a line and reading the meter. That was because she used 207 kilowatt hours of power but produced 345 with her own system.

It also helps that Watkins's home is designed to be energy efficient so she doesn't use a lot of power to cool it in the summer or very much propane to warm it in winter.

She had the house built 20 years ago from a plan she developed with architect Phil Gallegos. The Spanish-style building overlooking Lake Pueblo is well insulated and its windows are arranged to heat it in the winter and keep it cool in the summer. She averages $15 a month for the propane that provides space heat and hot water.

Watkins said she considered installing a photovoltaic system when the house was built, but it was prohibitively expensive then with a system able to power her house costing $400,000.

By 1999, she was able to use the money she'd saved up for the project and contracted with Altair Energy of Golden to have the system installed. The total cost came to $42,000 but she was able to get a $7,000 rebate available in Colorado then but no longer offered.

No, there's nothing wrong with the physicist's math skills. Watkins freely admits that it would have been cheaper to just stick with Aquila. Even using the 25-year warranty she got to model the system's cost over time, that still comes to $167 a month on top of the base Aquila will always charge for its back-up connection and not counting maintenance. Watkins hasn't had any maintenance costs and the batteries should last another five years, technicians say.

But Watkins, a longtime community activist and Catholic nun, freely admits that she had more in mind than cost: The solar cells in her backyard might mean that power companies will have to burn a little less coal or gas.

The biggest barrier to solar is the cost. Kirk Stokes, director of engineering at Altair, said that the rebate funded by an oil overcharge fund made the cost for many borderline, but when it expired, so did demand.

Prices have continued to drop, however. He said that a 4.2-kilowatt system like Watkins' would cost between $25,000 and $27,000 today, if mounted on a roof and batteries weren't included.

He said that 90 percent of Altair's customers don't get battery backups, which adds about 10 percent to the cost. Roof-mounted systems also are cheaper to install than freestanding arrays that have to be set on concrete bases.

But although most buyers finance their systems with low-interest home equity loans, costs are still a barrier. That's why Altair and other providers are strong supporters of Amendment 37, the renewable energy bill on the November ballot.

The measure, opposed by utilities, would require them to obtain 4 percent of their power from solar and half of that amount from residential systems they would have to finance for up to $2 a watt. That would still pay for only about a third of the cost of a 4.2-kilowatt system, but the amendment also requires the power companies to reimburse the customer one-for-one at the retail rate per kilowatt hour rather than the skewed retail-in, wholesale-out system used now.

"That's why Xcel and others are fighting against it so hard," Stokes said.

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