We got a late start and missed the 9AM workshop at Ijams Park, but we did make it out to see two of the local area homes on the Great American Solar Tour.

First we visited the West Knoxville home of Steve Smith, Executive Director of the Southern Alliance for Clean Energy.

Steve first showed us his Solar Tube "daylighting" system, which pipes sunlight into his kitchen and other rooms for natural lighting. He purchased the Solar Tubes from Homebuilder's Supply on Middlebrook Pike, who also did the installation. He said the 14" Solar Tubes with optional electric lights for nighttime use (using CFL bulbs) were about $650 each installed.

Next he showed us his solar water heating system. It's a sealed system that uses a glycol-based, freeze proof fluid, which is heated in two collector panels on the roof that are about 6' X 8' total, and an 80 gallon heat exchange/hot water tank.

The heated solution circulates from the collectors to the tank where the heat exchange takes place. Heated water from the heat exchange/storage tank then feeds into a standard 50 gallon electric water heater. The standard water heater provides backup, but rarely has to heat water because the input water is already heated.

While we were watching at around 11AM, the solution temperature in the collector was about 140 degrees. When the temperature difference between the collector fluid and water in the heat exchange tank reaches 12 degrees, an electric pump circulates the solution back to the collectors on the roof to be heated again. Steve said water in the heat exchange tank only loses a few degrees overnight.

There's a manual valve between the heat exchange tank and the standard water heater to mix in cold water if the solar heated water is too hot. Apparently, water in the collectors can reach 180 to 200 degrees in the summer. Steve said that he's only had the system for a little over a week, so he doesn't know yet how often it would be necessary to adjust the valve. One improvement I'd want is an automatic regulator to eliminate any manual adjustments.

Because he has only had the system for a short time, Steve doesn't know yet how much savings will result. It's a top of the line system that cost about $10,000 installed, and Steve noted there are other less expensive solutions. The system is made by Shuco and it was installed by Green Earth Services of Knoxville (865-769-7337).

Steve also has a solar photo-voltaic (PV) electric system on order, but because of tremendous demand the panels are back ordered for anywhere from two to four months.

The delay actually worked in Steve's favor, though. He told us the economic recovery bill passed by Congress just yesterday restores federal solar tax credits, eliminates the caps, and extends them for eight years.

Under the old program, homeowners could receive a one-third credit up to $2000. Now they can get one-third credit on the full installation cost. This will be significant on solar PV systems, which can cost up to $40,000 or more. Steve also said that extending the credits for eight years brings incentives and more certainty to the market that will encourage investment and increased production of solar panels for both PV and water heating applications.

Steve also mentioned that TVA is planning to increase the buyback from 15 cents to 20 cents per KWH for residential Green Power Generation Partners, further reducing the payback period for residential solar PV systems.

Steve noted that commercial installations can also get state grants, which along with federal tax credits and other TVA incentives can pay up to three-fourths of the cost for a solar PV system.

Our next stop was the home of Don and Jo Huising in West Knoxville. The Huisings have a 4.5KW solar grid-connected photo-voltaic (PV) system installed at their home. They were the first KUB residential customer to participate in the Green Power Generation Partners program. They have had their system for about three years, and in that time have paid virtually nothing for electricity and in some months make money.

From talking with Ms. Huising, however, it would seem their case is atypical. She said their average monthly usage is about 1000 KWH for a 3000 sq. ft. all-electric home, including heating and AC. My first question was, how did they accomplish that? She said "mainly, my son moved out." But, they have also upgraded to all energy efficient appliances, CFL lighting, improving insulation and minimizing heat loss, and a passive solar sun room which that helps heat their house in the winter.

They have 27 solar PV panels on their south-facing roof. It was installed about three years ago by Big Frog Mountain Corp. of Chattanooga. Ms. Huising said the cost was $28,000, which sounds like a bargain considering the typical cost is usually estimated at about $9K to $10K per KW. The panels have a 30 year warranty.

Someone asked about output degradation, and she said they noticed a slight decrease in output after about a year. On inspection, they found the panels were dirty with pollen and other dirt and debris. Her husband cleaned them off and power output returned to normal. She said they now clean them about once a year.

Ms. Huising showed us her electric bill for last month. They used 781 KWH, and generated 605 KWH. Because KUB charges about 8 cents per KWH but buys back generated electricity for 15 cents per KWH, they received a $90 credit on their $69 electric bill, making their net bill for the month -$21.

(I'm not clear on why this doesn't calculate out according to KUB's rates, but I presume it has to do with taxes and fees and other adjustments. It may have included their water bill, too, but I don't recall.)

We didn't get all the technical details of their installation, but we did take a look at the meters and control panels and it's an elaborate setup. There are three controller devices of some type made by OutBack Power Systems. These fed in to a power inverter (Sunny Boy by SMA). From there the power goes to a "co-generation" meter which meters how much power is generated, then through an isolator and emergency cut-off to disconnect the solar power from the grid when utility workers need to work on the public power lines and then to a distribution box. There is also a "house" meter which measures consumption, and it was indeed running backwards.

Another "extreme energy efficient" home on the tour was David Bolt's home in Harriman. We didn't make it over to that one, but David's home uses all the solar and other energy efficiency tricks in the book to generate more power than it uses. David's company, Sustainable Future, is another local area provider of solar hot water and PV systems along with other products for "sustainable lifestyles."

The solar tour was a great opportunity to get a first hand look at actual installations. Thanks to the participants who opened up their homes to help raise awareness of what's possible. There was surprisingly good turnout, with people coming and going at both stops (several driving hybrids). So there's clearly a lot of interest, and most folks seemed more interested in the environmental rather than the financial benefits.

Systems are still relatively expensive and paybacks are years down the road for most installations. But with increasing production, decreasing system costs, rising energy costs, and heightened awareness of environmental costs associated with fossil fuels, solar systems are becoming more popular and are closer than ever to being financially cost effective.

Both Steve Smith and Ms. Huising stressed, however, that before investing in any solar systems homeowners should do everything they can to make their homes as energy-efficient as possible, otherwise they are just wasting money. That's good advice for everyone, regardless of whether they are planning solar upgrades.