Aspen, county to encourage solar electricity
September 16, 2008
ASPEN ” Is solar energy still environmentally conscious if production exceeds demand and the power never gets used?
Yes, but not as much as a system that puts that excess energy back in the system, say building department staff in the city of Aspen and Pitkin County.
The departments are currently in the process of re-writing their building codes. As they do so, they are looking to encourage homeowners who must mitigate for outdoor energy use (in the form of a pool, spa or snowmelt system) to use more photovoltaic power, instead of building unnecessarily large solar hot water systems. Photovoltaic systems are arguably more desirable than solar hot water systems for a community ” especially one with many second homes ” because any excess solar energy can be returned to the grid and used by others instead of being wasted.
Though photovoltaic systems cost about three times as much as solar hot water systems, they are also three times as effective, said Biospaces, Inc. president Jeff Dickinson, who has been advising the building departments. Thus, the building staff plans to propose that homeowners who choose to mitigate with photovoltaic systems be allowed to build systems one-third the size, said Dickinson.
The current Renewable Energy Mitigation Program requires homeowners to mitigate for exterior energy use ” but it doesn’t specify what type of system should be used. As a result, many homeowners choose cheaper solar hot water systems.
The problem, according to Aspen’s chief building official Tony Fusaro, is that a solar hot water system designed to melt snow (or mitigate for the snowmelt with a radiant heat system) has little purpose in the summer months when hot water demand is often limited to domestic uses.
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In fact, he explained, the systems have to be designed with a heat sink so that they don’t overload. A snowmelt system, for example, might continue to run hot water under the driveway, just to get rid of the heat. The exceptions are solar hot water systems that heat a snowmelt system in the winter and a pool in the summer.
To prevent homeowners from building huge and unnecessary hot water systems as mitigation, a 2003 rewrite of the code limited solar hot water systems to 500 square feet, said Fusaro.
The newest code update may require homeowners who choose solar hot water systems to mitigate for 100 percent of their outdoor energy use, said Dickinson.
Homeowners who choose photovoltaics, however, will only be required to mitigate for 30 percent of their outdoor energy use. Currently, all homeowners have to mitigate for 50 percent of their energy use, regardless of what system they use.
The new code should be presented to elected officials within the next month or two, said Pitkin County plans examination manager Denis Murray.
Meanwhile, both local officials and those in the alternative energy field say photovoltaic systems continue to grow in popularity of their own accord.
Mike Tierney, of Aspen Solar, explained that for many years, solar hot water has been far more popular than photovoltaic systems. Only recently, he said, has he seen an increased interest in photovoltaics. Aspen Solar sells both types of systems, he said.
Sandy Pickard, the business manager at Solar Energy International and one of the Solar Sisters on KDNK’s show, agreed, noting that SEI will hold roughly 35 photovoltaic courses this year and only two courses in solar hot water systems.
Advances in photovoltaic technology, along with the ability to sell energy back to the grid, have made solar electric systems “the hottest item” in the renewable energy field right now, she said.
Tierney acknowledged the benefits of photovoltaic systems that can feed energy to the grid all year long ” but noted that he would hate to see solar hot water be “pushed aside.” He hoped that the updated code would continue to incentivize solar hot water systems that do work year round (such as those that melt snow in the winter and heat pools in the summer.) He also hoped the building departments would encourage hybrid systems that use both solar hot water and solar panels.