Technology.am (Aug. 24, 2009) — As you are aware the world’s oil supply continues to dry out every day. At the present rate of consumption, coal will run out in 130 years, natural gas in 60 years and oil in 42 years.
Image courtesy: greenecon.net
As a solution to this problem Derek Abbott, Professor of Electrical Engineering at the University in Australia states that a solar-hydrogen economy is more sustainable and provides a higher total power output potential. He argues about the major non-renewable and renewable energy sources.
Nuclear fission: While nuclear fission power plants may at first seem to have the economic advantage, they have “hidden costs” (the biggest being the $6 billion cost to decommission after a 30 or 40 year lifetime). In addition, nuclear fission isn’t sustainable i.e. there would only be five years supply of uranium; and thorium considered a substitute if it meets the world’s energy needs.
Nuclear fusion: Abbott argues that nuclear fusion, which usually involves the fusion of deuterium and tritium, is not actually clean as Tritium requires weekly cleaning. In addition, Tritium is obtained by reacting neutrons with lithium whose reserves would last about 100 years if it were to supply the world’s energy along with other usages at present such as in batteries, glass, ceramics, and lubricants.
Wind: Abbott shows that wind power is economically uncompetitive with solar power in all locations except cold regions with poor sun levels.
He emphasizes that we need to preserve at least some of our remaining oil for uses other than energy – such as lubricating the world’s engines, for making dyes, plastics, and synthetic rubber. Similarly natural gas has industrial applications for making ammonia, glass and plastics, and coal for making soap, aspirin, tires, and other materials.
Hydroelectric: Hydroelectricity currently provides 20% of the world’s electricity. However, hydroelectricity could not supply the whole world’s power due to the limited availability of waterways.
Geothermal: Geothermal power has shown to be cost-effective and sustainable, due to the large amounts of heat contained in the Earth, but much of the energy is diffused and unrecoverable.
Solar: Abbott considers solar power as an alternative energy source especially low-tech solar thermal collectors rather than high-tech silicon solar cells. Solar cells require large amounts of water and arsenic; to manufacture enough solar cells to power the world would require 6 million tonnes of arsenic, while the world’s supply is estimated at about 1 million tonnes.
Today, the world’s energy consumption is currently 15 TeraWatts (TW). The total solar energy that strikes the Earth is 166 Petawatts (PW). Even with 50% of this energy being reflected back into space or absorbed by clouds, the remaining 83 PW is more than 5,000 times our present global energy consumption.
In contrast, the above sources of renewable energy (wind, hydroelectric, and geothermal) can supply less than 1% of solar power potential. The challenge, of course, is how to harness this large source of renewable, sustainable solar energy.
On the other hand, solar thermal collectors are specifically designed to operate under hot temperatures. The idea is to use a curved mirror to focus sunlight to boil water and create steam, which is then used to power, for example, a Stirling heat engine in California’s Mojave Desert to produce electricity.
Abbott says, solar farms should be distributed widely throughout the world in order to avoid geopolitical stresses and minimize transportation costs. Solar farms of one or two square km could be built in deserts in many regions.
Hydrogen: After connecting these solar farms to the local electricity grid, the electricity could then be used to electrolyze water to produce liquid hydrogen to run our vehicles. And the next step would be to power public transport, such as buses, using liquid hydrogen.
According to Abbott, running vehicles on hydrogen is superior in terms of sustainability as vehicles that burn hydrogen simply emits clean water vapor.
As Industry already handles 50 million tonnes of hydrogen annually, therefore, the question of safe handling does not arise. A study shows that it is more economical to transport hydrogen by truck to refueling stations rather than perform on-site electrolysis. Abbott suggests to liquefy the hydrogen for storage.
Overall, Abbott’s message is that there exists a single technology that can supply the world’s energy needs in a clean, sustainable way: solar-hydrogen.