Most of the technology we need to switch from fossil fuels to clean and renewable energy already exists — the greatest hurdles to making...

sunrise-over-earthMost of the technology we need to switch from fossil fuels to clean and renewable energy already exists — the greatest hurdles to making the shift involve planning and politics.

Overcoming those hurdles could yield a 30 per cent decrease in global power demand, according to Mark Z. Jacobson of Stanford University and Mark Delucchi of the University of California-Davis.

Featured in a cover story in the November issue of Scientific American, Jacobson and Delucchi present new research that maps out and evaluates a plan for powering the entire world on wind, water and solar energy. Their analysis, which includes an assessment of the materials needed and costs, concludes it will ultimately be cheaper than either sticking with fossil fuels or going nuclear.

The key, they say, is making a massive commitment to using wind, water and solar energy to generate electrical power, and eliminating combustion energy for both electricity and transport.

Jacobson and Delucchi point to the large inefficiencies of both fossil fuels and biomass combustion. Using petrol to power a vehicle, for example, results in at least 80 per cent of the energy produced being wasted as heat.

With vehicles that run on electricity, it’s the opposite. Roughly 80 per cent of the energy supplied to the vehicle is converted into motion, with only 20 per cent lost as heat. Other combustion devices can similarly be replaced with electricity or with hydrogen produced by electricity.

Jacobson and Delucchi used data from the US Energy Information Administration to project that if the world’s current mix of energy sources is maintained, global energy demand at any given moment in 2030 would be 16.9 terawatts, or 16.9 million megawatts.

They then calculated that if no combustion of fossil fuel or biomass were used to generate energy, and virtually everything was powered by electricity — either for direct use or for hydrogen production — the demand would be only 11.5 terawatts. That’s only two-thirds of the energy that would be needed if fossil fuels were still in the mix.

To convert to wind, water and solar, the world would have to build wind turbines; solar photovoltaic and concentrated solar arrays; and geothermal, tidal, wave and hydroelectric power sources to generate the electricity, as well as transmission lines to carry it to the users. However, the long-run net savings would more than equal the costs, according to Jacobson and Delucchi’s analysis.

“If you make this transition to renewables and electricity, then you eliminate the need for 13,000 new or existing coal plants,” Jacobson said. “Just by changing our infrastructure we have less power demand.”

Jacobson and Delucchi chose to use wind, water and solar energy options based on a quantitative evaluation that Jacobson conducted last year of about a dozen different alternative energy options that were getting the most attention in public and political discussions and in the media. He compared their potential for producing energy, how secure an energy source each was, and their impacts on human health and the environment.

He determined that the best overall energy sources were wind, water and solar options. His results were published in Energy and Environmental Science.

The Scientific American article provides a quantification of global solar and wind resources based on new research by Jacobson and Delucchi.

Analysing only on-land locations with a high potential for producing power, the researchers found that even if wind were the only method used to generate power, the potential for wind energy production is 5 to 15 times greater than what is needed to power the entire world. A comparable calculation found that solar energy could produce about 30 times the amount needed.

If the world built just enough wind and solar installations to meet the projected demand for the scenario outlined in the article, an area smaller than the borough of Manhattan would be sufficient for the wind turbines themselves. Allowing for the required amount of space between the turbines boosts the needed acreage up to 1 per cent of Earth’s land area, but the spaces between could be used for crops or grazing. The various non-rooftop solar power installations would need about a third of 1 per cent of the world’s land, so altogether about 1.3 per cent of the land surface would suffice.

The study further provides examples of how a combination of renewable energy sources could be used to meet hour-by-hour power demand, addressing the commonly asked question, given the inherent variability of wind speed and sunshine, can these sources consistently produce enough power? The answer is yes.

Expanding the transmission grid would be critical for the shift to the sustainable energy sources that Jacobson and Delucchi propose. New transmission lines would have to be laid to carry power from new wind farms and solar power plants to users, and more transmission lines will be needed to handle the overall increase in the quantity of electric power being generated.

The researchers also determined that the availability of certain materials needed for some of the current technologies — such as lithium for lithium-ion batteries or platinum for fuel cells — are not currently barriers to building a large-scale renewable infrastructure. But efforts will be needed to ensure that such materials are recycled and potential alternative materials are explored.

Finally, they conclude that perhaps the most significant barrier to the implementation of their plan is the competing energy industries that currently dominate political lobbying for available financial resources. But the technologies being promoted by the dominant energy industries are not renewable and even the cleanest of them emit significantly more carbon and air pollution than wind, water and sun resources, say Jacobson and Delucchi.

If the world allows carbon- and air pollution-emitting energy sources to play a substantial role in the future energy mix, Jacobson said, global temperatures and health problems will only continue to increase.

Greenbang

  • Ron Dickerson

    October 20, 2009 #1 Author

    According to Science Desk Reference American Scientific. New York: Wiley, 1999: 180.the standardized earth land surface area= 57,500,000 SQ. Miles

    575,500 Sq Miles? Manhattan is a lot bigger than it appears!

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