Tuesday, October 20, 2009

Lessons from the Solar Decathlon

This year's Solar Decathlon ended on Sunday, Oct. 18, and was a leap forward from other years in several respects. For those who are not familiar with this contest, it is sponsored by the Department of Energy, occurs every 2 years, and involves 20 universities from around the world. The goal is to create an energy efficient residence that is judged in numerous categories. The Solar Decathlon houses are constructed on the Mall and are open to the public for about 10 days, with some house closures scheduled for judging.
The DOE conducts this contest partly to educate the public in energy conservation and efficiency techniques, showing the values of different construction types, insulation value, window design and construction, thermal solar uses, and the latest in photovoltaics. There is always an exhibit at the center of the "street" of houses with interactive displays, docents give tours, and each university team has its members & volunteers available to describe the specific advantages and design features of its house.
The rules for the decathlon change from event to event, and, this year, the DOE decided that the teams could not set up battery storage systems for their solar arrays. All of the houses were connected to the grid with net metering, under the DOE assumption that the standard homeowner who installs a solar photovoltaic system would utilitze net metering (if the solar system doesn't provide enough power for the house, the power company will supply the shortage; if the solar system generates more power than needed at that time, the excess power is "sold" back to the power company and the electric meter runs backwards). With this system, there is virtually no power generated for use at night, and the house must draw from the electric grid. Adding storage battery capacity to a new solar installation adds significant cost, but allows the homeowner to store generated energy for use when the photovoltaics aren't sufficient for the need.
The houses were judged on their energy generation (net metering), architecture, market viability, engineering, comfort zone, hot water, appliances, home entertainment, lighting design, and communications. Although the University of Alberta's SolAbode ranked 10th in the architecture (and 6th overall), I found this house to be gorgeous, made from natural materials blended in a warm and stylish design. Team Germany came in 1st overall, with a really innovative house "skin" made of super-thin solar panels. This house combined many advanced technological concepts in a modern package, achieving great results with a larger square footage of living space than other teams attempted. To my taste, the ultra-modern styling left me a bit cold, but it was a worthy winner. Team California was third, with a nice twist to the solar model in that they turned their modules at angles to create a small courtyard effect, quite different from the standard box.
The entertainment category was also interesting. Each of the teams that we visited used LED TVs, which use approximately 42% less energy to run than LCDs and dramatically less than a plasma TV, which is a noted energy hog. The two companies chosen for the TVs were Sharp and  Samsung. I don't know if any other manufacturers are in the LED TV market, but these two were prominent.
As for sustainabililty and environmental friendliness, this aspect is not emphasized in the Solar Decathlon, the DOE's main thrust being energy efficiency. Although the teams made efforts (some more than others) to use recycled materials, there was no concerted drive to find materials whose manufacture doesn't pollute or generate undue amounts of greenhouse gasses, etc. Using local materials was clearly secondary to the stated goal of conserving and generating energy. Not a crime, just an observation.
Take a look at the houses and their special features on the official website. It was a real education, and I look forward to the next Solar Decathlon. 

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