Evergreen Online. February / March 2003

Evergreen Online

The Newsletter of Wirral Green Alliance

Digest Edition

February 2003 / March 2003

In this month's online edition:

Tower of Power: The proposed Australian solar tower

Grow Trees to Drive Cars

TOWER OF POWER
Australia Plans 1km High Solar Tower An Australian power company is planning to build the world's tallest structure; a solar tower in the middle of the outback. The project is part of a global campaign to encourage the use of more renewable energy. Enviromission says the tower, at a proposed height of one kilometre (3,300 ft), will be more than twice the size of the world's current tallest freestanding building, the Canadian National Tower in Toronto. The one billion Australian dollar (Ł358m) project is being backed by the Australian Government, and is expected to be completed in 2006 in the remote Buronga district in New South Wales. If successful, the structure could provide enough electricity for 200,000 homes. It will save more than 700,000 tonnes of greenhouse gases which may otherwise have been emitted by coal- or oil-fired power stations. Enviromission chief executive officer Roger Davey told Reuters news agency: "Initially people told me 'you're a dreamer', there's no way anything that high can be built, there's no way it can work. But now we have got to the point where it's not if it can be built, but when it can be built." The proposed structure will have a width similar in size to a football field and will stand in the centre of a huge glass roof spanning 7km (4.3 miles). The sun will heat the air under the glass roof, and as it rises an updraft will be created in the tower, allowing air to be sucked through 32 turbines. The turbines will then spin, generating power 24 hours a day. The tower was invented by German structural engineers Schlaich Bergerman, who built a 200-metre-high demonstration power plant in Manzanares, Spain, in 1982. The tower proposal has received the support of the Australian and New South Wales governments, which have defined it as a project of national significance. The authorities plan to fit the tower with high intensity obstacle lights to prevent aircraft from crashing into it. Link: www.wentworth.nsw.gov.au/solartower/default.asp
	Artist's impression of the proposed tower

Grow Trees to Drive Cars

The best way to make the UK's road transport green could be a massive tree-growing programme, researchers say. They say there is considerable potential for producing hydrogen and alcohol fuels from fast-growing trees like willows.

A quarter of all the UK's agricultural land would be enough to fuel the country's entire road transport sector, they believe. But they say it will be several decades before hydrogen is a sensible choice as a transport fuel. The researchers are from three think-tanks: the Energy Saving Trust, the Institute for European Environmental Policy, and the National Society for Clean Air (NSCA).

They have produced a report, Fuelling Road Transport - Implications for Energy Policy. In it they argue that the rapid expansion of hydrogen as a fuel for transport could in fact damage the environment rather than help it. This is partly because electricity is needed to produce hydrogen from a source containing carbon, and there is a net loss of energy in converting it for use in motor vehicles. But another reason, the report says, is because there are greater savings in emissions to be made by using electricity from renewable sources to replace old power stations.

One of the authors, Richard Mills, said: "There is no doubt that, long-term, the transport sector could use substantial amounts of hydrogen from renewables. But in the medium term hydrogen will come from natural gas. It would make more sense to burn that gas directly in vehicles".

"A premature 'dash for hydrogen' could have an environmental downside, which can be avoided by encouraging the more efficient use of petrol and diesel hybrid technologies, and developing transport fuels from biomass." Tim Brown, of the NSCA said "You'll get a bigger bang for your carbon buck by taking out old, inefficient power stations."

The report says there is enormous potential for using biomass - vegetable matter - to make fuel for road vehicles. It says: "Biomass offers a cheaper and earlier route than renewable electricity to reducing carbon emissions via a hydrogen-fuelled transport system. As an indication of the potential contribution, 25% of UK agricultural land planted with indigenous wood crops converted to methanol, ethanol or hydrogen could in the long term satisfy most or even all UK road transport fuel demand. This outcome would, however, be dependent on relative costs and a large number of technical factors."

The authors stress they are not suggesting turning over a quarter of Britain's farmland to providing fuel, but simply pointing out how easy it would be to produce enough.

The report says there are "compelling environmental and strategic arguments for reducing the carbon intensity of the UK energy mix, and in particular the road transport sector, which is uniquely oil-dependent."

Clean Air Initiative