Monday, February 4, 2008

Harnessing the Sun’s Energy/Across the Universe


The energy in sunlight striking the earth for 40 minutes is equivalent to global energy consumption for a year -- Zweibel et al., 2008

Energy from the sun travels to the earth in the form of electromagnetic radiation similar to radio waves, but in a different frequency range (Natural Resources Canada). Available solar energy is often expressed in units of energy per time per unit area, such as watts per square metre (W/m2). I’m told that the amount of energy available from the sun outside the Earth’s atmosphere is about 1367 W/m2, which I’ve calculated is nearly the same as a high power hair drier for every square meter of sunlight (okay, someone told me that too!)…

“Solar energy obviously harvests the sun, which on its own currently provides 99% of the world’s natural energy,” say authors of the University of Michigan website for alternative energy.
The use of solar fields and solar panels is in effect today, just not on an extremely large scale. Some of the downsides of solar energy include the fact that they are relatively expensive to build at first, and that they only harvest energy when the sun is out.

According to Natural Resources Canada “There are many ways that solar energy can be used effectively. Applications of solar energy use can be grouped into there are three primary categories: heating/cooling, electricity production, and chemical processes. The most widely used applications are for water and space heating. Ventilation solar air heating is also growing in popularity. Uptake of electricity producing solar technologies is increasing for the applications photovoltaics (primarily) and concentrating solar thermal-electric technologies. Due to recent advances in solar detoxification technologies for cleaning water and air, these applications hold promise to be competitive with conventional technologies.”

Solar energy has the following advantages over conventional energy:
  • The energy from the sun is virtually free after the initial cost has been recovered.
  • Depending on the utilization of energy, paybacks can be very short when compared to the cost of common energy sources used.
  • Solar and other renewable energy systems can be stand-alone; thereby not requiring connection to a power or natural gas grid.
  • The sun provides a virtually unlimited supply of solar energy.
  • The use of solar energy displaces conventional energy; which usually results in a proportional decrease in green house gas emissions.
  • The use of solar energy is an untapped market.
By 2050 solar power could end U.S. dependence on foreign oil and slash greenhouse gas emissions.” suggest Zweibel et al. (2008). Their recent article in Scientific American (January, 2008 issue) suggests a plausible scenario by 2050: 69 percent of electricity in the U.S. and 35 percent of its total energy would be supplied by solar energy. This would, of course, involve a massive switch from coal, oil, natural gas and nuclear energy currently in use in North America.

Here’s what it would look like: a vast area of the Southwest would be covered in photovoltaic cells with excess daytime energy being stored as compressed air in underground caverns (to be tapped during nighttime). Large solar concentrator power plants would deliver a direct current power transmission backbone of solar electricity across the country.

In order for this scenario to happen, though, $420 billion in subsidies from 2011 to 2050 would be required to fun the infrastructure and make it cost-competitive, says the article. How likely is that? If the government recognizes that the payoff is far greater to the investment, then it is a good bet that this could indeed happen. Here are some of the advantages: solar panels consume little or no fuel, saving billions of dollars annually. The solar infrastructure would replace an inefficient and fuel-glutting system of coal-fired power plants and gas plants. No oil would be imported, along with the obvious headaches associated with that endeavor. And here’s the part I really like: solar technology is virtually pollution-free, and would reduce greenhouse gas emissions by 1.7 billion tons a year. Another 1.9 billion tons of gas emissions would be displaced by plug-in hybrids refueled by the solar power grid, according to Zweibel et al. Furthermore, these authors contend that that by 2050, U.S. carbon emissions would be 62 percent below 2005 levels and suggest this would as much as end global warming. The authors further suggest that by 2100 renewable energy could generate 100 percent of the U.S.’s electricity and more than 90 percent of its energy.

According to the U.S. Department of Energy, here's a look at some things we can expect in the future from solar technologies:
“All our buildings will feature energy-efficient design, construction, and materials as well as renewable energy technologies. In effect, each building will both conserve energy and produce its own supply, to be one of a new generation of cost-effective "zero-energy buildings" that have no net annual need for nonrenewable energy.
"In photovoltaic research and development, there will be more breakthroughs in new materials, cell designs, and novel approaches to product development. In a solar future, your mode of transportation—and even the clothes you wear—could produce clean, safe electric power.
"With today's technology roadmaps to lead the way, concentrating solar power will be fully competitive with conventional power-generating technologies within a decade. Concentrating solar power, or solar thermal electricity, could harness enough of the sun's energy to provide large-scale, domestically secure, and environmentally friendly electricity, especially in the southwestern United States.
"The enormous solar power potential of the Southwest—comparable in scale to the huge hydropower resource of the Northwest—will be realized. A desert area 10 miles by 15 miles could provide 20,000 megawatts of power, and the electricity needs of the entire United States could theoretically be met by a photovoltaic array within an area 100 miles on a side.
Within 10 years, photovoltaic power will be competitive in price with traditional sources of electricity.
"Solar electricity will be used in an electrolysis process that separates the hydrogen and oxygen in water so the hydrogen can be used in fuel cells for transportation and in buildings.”


Zweibel, K., J. Mason and V. Fthenakis. 2008. By 2050 solar power could end U.S. dependence on foreign oil and slash greenhouse gas emissions. In Scientific American, January 2008 issue.





Nina Munteanu is an ecologist and internationally published author of novels, short stories and essays. She coaches writers and teaches writing at George Brown College and the University of Toronto. For more about Nina’s coaching & workshops visit www.ninamunteanu.me. Visit www.ninamunteanu.ca for more about her writing.

4 comments:

Jean-Luc Picard said...

Solar energy is a great step forward. It should be promoted more. Good post, Nina.

sfgirl said...

Thanks, Jean-Luc. I'm quite excited by the positive perspectives of governments toward promoting this excellent energy source.

Anonymous said...

Thank you for your insights. Looking forward to residential applications of this technology, and suggest a government subsidy would be in order until economies of scale make this affordable for all.
Captain K

sfgirl said...

Good point, Captain K. I would also like to see governments fully supporting this technology by using various motivational incentives to both industries and private users.