March 6, 2008

The Solar Power Push

Everyday it blazes across the sky and shares more energy with the Earth than humans could ever hope to use. The greatest energy factories on Earth use its never ending supply of high power radiation to assimilate carbon, produce oxygen, and feed the world. If we add up all the power that could ever be harvested by our oil and coal deposits, it would laugh and produce the same in a 24 hour span. Yet everyday we see the sun rise and set and rarely contemplate just how important that glowing ball of plasma is.

The energy from sunlight falling on only 9% of the California's Mojave Desert could power all of the United States' electricity needs if the energy could be efficiently harvested. Really? So if we could dedicate 9% of unusable desert land to solar energy production we could turn all of our coal and gas power plants off? That sounds like a great future technology, but the truth is with the right incubation and nurturing of technology this type of energy production is just around the corner.

A team at Northwestern recently discovered a new way to make solar cells that boosted their efficiency "by approximately 40 percent and the power conversion efficiency from approximately 3 to 4 percent to 5.2 to 5.6 percent." I know those numbers don't mean a lot to you non-science folks, but they are quite amazing for such a simple solution. The group is continuing to do work on recovering efficiency within the system and the results look promising to further increasing the ability to store solar electricity. There are numerous advances within the efficiency of solar capture and conversion.

A great advantage to solar cells is their ease of production. Many cells are now produced just like a newspaper, with huge sheets of malleable plastic being printed with the solar capture machinery by the roll. A small startup company can make small solar cells using an inkjet printer. This means that in the future large quantities of commercial products can be produced to meet consumer demand with little capital investment. A major concern for massive production though is the pollution that solar cells may make. Production of solar cells includes the use of toxic heavy metals such as lead, mercury and cadmium. But with proper monitoring and capture strategies it has been shown that "producing electricity from solar cells reduces air pollutants by about 90 percent in comparison to using conventional fossil fuel technologies.

The big barrier to commercial potential for solar lies in the startup and installation costs. But with continued research the cost of components and manufacturing will continue to decrease. A recent publication showed that efficiency was not hampered when some of the most expensive materials are replaced by good ole steel. Conductively coated glass sheets have been the standard for making solar cells but now new production methods allow manufacturers to substitute low cost, thin steel sheets. The glass sheets account for more than 30% of usual production costs but steel is extremely inexpensive per pound when compared to the glass sheets.

And while production costs will start to go down with increased efficiency and larger production infrastructure, right now the demand is outpacing the supply. This is a double-edged sword as an increase in consumer demand indicates growing public support for residential and commercial solar technology, but also brings with it an increase in price. The cost of photovoltaic (PV) cells has declined steadily over time, but in the last three years the price per watt has risen from $6.93 in 2005 to $7.25 in 2006 and $7.62 in 2007. has the full economic results for PV costs.

The supply though will continue to rise to meet the demand. Already we have seen a huge boom in renewable energy plants, not just solar. This investment in energy supply will eventually lead to cheaper electricity costs as mining for solar and wind power takes very little sustained investment. Think about the front-end cost for coal consumption, huge machines and a dangerous work environment that requires many laborers, those things all cost vast quantities of money. Now consider that mining for solar energy consists of waiting for the sun to rise and for wind technology sitting waiting for the breeze. The reduced cost of obtaining an energy supply should be passed onto consumers (unless we let the electric companies run like oil companies) by way of decreased cost per kilowatt hour. Now this decrease in cost will take a while as the supply and demand must settle in and reach an equilibrium but it should be encouraging to know that it costs nothing to make the sun rise or listen to the wind blow.

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