KEY POINTS:
Emissions-free electricity could be generated from sand and sunshine, a Waikato University scientist says.
Professor Earl Bardsley said World Environment Day tomorrow was an excellent time for people to ponder alternatives to coal or nuclear-powered power stations.
New Zealand is hosting the 2008 World Environment Day, and it has a theme of carbon reduction.
Prof Bardsley has been invited to speak at the Oxford Round Table in Britain in August about his proposal for eco-friendly silicon power stations.
The Oxford Round Table is a not-for-profit educational organisation, which provides a forum to discuss contemporary issues affecting the public good.
Prof Bardsley said combating global warming would not necessarily be achieved through the Kyoto Protocol or carbon trading schemes, but instead required an alternative sustainable energy economy.
At present, the only alternative economy was based on hydrogen which burned cleanly to produce only energy and water but there were problems with its safety, delivery and storage.
He said silicon was the most abundant element in the earth's crust and occurred in large, natural concentrations as the white silica sand in many desert regions. Using parts of the world's desert regions as an energy source would make good use of unproductive land.
"In contrast, seeking sustainability through the use of biofuels will displace agricultural land and continue to put pressure on food prices," Prof Bardsley said.
"Silicon is the perfect renewable fuel alternative to coal or nuclear power stations. In energy terms, silicon is comparable to coal because both burn to give the same amount of energy," he said.
"Silicon power plants have the potential to be a substitute for base load nuclear power stations."
Base load electricity is generated at a constant rate and not subject to the fluctuations associated with renewable energy.
Prof Bardsley said a stockpile of silicon just a few metres thick over a square kilometre had the same energy content as all of New Zealand's hydro storage lakes put together.
Prof Bardsley, who specialises in hydro-power, said eco-friendly silicon power stations would operate in a similar way to coal-fired power stations but would use silicon instead of carbon.
However, silicon was not an energy source in itself, because it always occurred in nature in its oxidised form - white quartz sand. Just as hydrogen can be created by using electrolysis (which requires energy), silicon would need to be produced from smelters using electricity to reduce that white sand to the silvery metallic silicon which could then be burnt.
Prof Bardsley said solar energy could be used to create the silicon from sand at smelters on the desert margins.
While the silicon would then have to be transported, this could eventually be done using silicon-powered bulk carriers, he said.
A large solar power system in Australia could provide silicon fuel for a modified Huntly power station, he said.
There was no direct research yet about silicon power stations, but Prof Bardsley said work was already underway in the silicon chip industry to develop carbon-neutral methods of making small amounts of silicon, and research in Japan was looking at adapting this to large-scale silicon production.
He said Singapore, China or Abu Dhabi were likely to be the first to build prototype silicon power stations.
Prof Bardsley's silicon power ideas are to be published soon in the Natural Resources Research journal.
- NZPA
