Solar Energy Exploratorium: Alternative Energy Education on the American River

The purpose of the Solar Energy Exploratorium (SEE) is to provide our students hands-on opportunities to encounter the many ways solar energy impacts our daily lives and the phenomenal potential solar power has to transform our society in positive ways. Our food, the weather, the hydrologic cycle that provides and purifies the water we drink, even the fossil fuels we burn in our cars, all ultimately derive their energy source from the sun.28,750 BTU Solar Hot Water Heater at MaLode

Today, the United States currently employs among the lowest percentages of solar power use in the industrialized world, less than 1%. Yet solar is one of the fastest growing and potentially the most promising type of energy that provides an environmentally sensible alternative to the fossils fuels that are creating so many problems for our society. In fact, if properly developed, solar energy could provide 65% of our total energy needs by the year 2050 (Scientific American January 2008 issue). Unfortunately, the type of solar power that has the greatest potential to achieve this, concentrating solar, is largely unknown to the American public and benefits from virtually no public policy support. At the Exploratorium you will have an opportunity to understand how this can and should be changed.

Another solar option we are all familiar with, photovoltaic cells, have quadrupled in energy efficiency from 3% to 12% in the past decade and will undoubtedly also contribute significantly to the coming solar transformation. While concentrating solar is installed as “solar farms”, PV cells are easily installed in a decentralized or “distributed” fashion that allows individuals and even whole communities to go “off the grid”. Our students learn that the belief that PV cells aren’t effective in cloudy weather or in Northern locations such as Seattle is simply incorrect. In fact, the American Institute of Architects estimates that by devoting one south facing wall to PV, the average building in Seattle has 6 times the sun exposure necessary to provide for all its electrical needs. This is using current efficiencies of 12%. Imagine how the 28% efficient panels currently being constructed in research labs will increase the ability of individuals to become energy self-sufficient!

Another realization our students will share is that the most efficient type of solar technology of all is not concentrating solar or photovoltaics, rather it is the thermal solar hot water heater. All too frequently neglected because it lacks technological sex appeal and is less profitable to install, solar hot water heating can replace the approximately 33% of one’s domestic energy which is used to heat water with a cheap, reliable, simple solar solution that you can construct from salvaged materials and install yourself. Doing the math gives some surprising results.

You may know that the performance of thermal solar systems is measured in British Thermal Units (BTUs) while photovoltaic solar electric systems are measured in kilowatt hours (kW/hrs). One of the four solar thermal systems we have installed at the River Center uses a progressive tube 50-gallon water filled heat exchanger that produces 28,750 BTUs. Converting this to Kilowatt-hours, we multiply by .0002931 resulting in 8.43 Kilowatts. An 8.4 Kw photovoltaic system would cost approximately $10,000 per kW or $84,000. This compares with the $3,500 to $4,000 retail value of our solar thermal system. Clearly, for heating water the solar thermal system is approximately 20 times more cost efficient. From an energy standpoint it is also six times more efficient than PV and three times more efficient than concentrating solar!

If you or your students would benefit from learning such information about solar energy, plan a visit to the SEE. You can take home some plans to build your own thermal “box” hot water heater that can be constructed for less that $300. Remember, it always helps to conserve energy (go lean) first, choose an alternative energy source (go clean) second, and finally, save some green by choosing the most cost efficient as well as the most environmentally responsible solutions to your energy needs. More often than not, solar is a great choice!