Virgin Earth Challenge

The Virgin Earth Challenge is a competition offering a $25 million prize for the first person or organization to come up with a way of scrubbing greenhouse gases out of the Earth's atmosphere to avoid global warming. The prize was conceived and financed by Sir Richard Branson, a successful British entrepreneur, and was announced in London on 9 February 2007 by Branson and former US Vice President and 2007 Nobel Prize winner Al Gore, creator of the 2006 film An Inconvenient Truth on climate change.

The challenge

The Virgin Earth Challenge is similar in concept to other high technology competitions, such as the Orteig Prize for flying across the Atlantic, and the Ansari X Prize for spaceflight. The prize will be awarded to the first scheme that is capable of removing one billion metric tons (= 1 gigaton) of carbon dioxide from the atmosphere per year for 10 years (at present, fossil fuel emissions are around 6.3 gigatons per year). $5 million of the prize will be paid at the start of removal operations, with the remaining $20 million paid after the successful completion of the scheme at the end of the 10 year period.

The prize will initially only be open for five years, with ideas assessed by a panel of judges including Richard Branson, Al Gore and Crispin Tickell (British diplomat), as well as climate scientists James Hansen, James Lovelock and Tim Flannery. If the prize remains unclaimed at the end of five years the panel may elect to extend the period.

Around two hundred billion metric tons of carbon dioxide have accumulated in the atmosphere since the beginning of the industrial revolution, raising concentrations by more than 100 parts per million (ppm), from 280 to more than 380 ppm. The Virgin Earth Challenge is intended to inspire inventors to find ways of bringing that back down again to avoid the dangerous levels of global warming and sea level rise predicted by scientific organisations such as the Intergovernmental Panel on Climate Change.

"Entrants must submit a commercially viable design (the “Design”) to achieve the net removal of significant volumes of anthropogenic, atmospheric greenhouse gases each year for at least 10 years without countervailing harmful effects (the “Removal Target”). The removal achieved by the Design must have long term benefits (measured over say 1,000 years) and must contribute materially to the stability of the Earth’s climate."

Contenders

GRT Air Capture Device

According to the Earth Institute at Columbia University, Global Research Technologies, LLC has demonstrated a prototype device capable of capturing 10 tons of carbon dioxide per square meter per year; a device of 10 meters by 10 meters would be able to capture 1,000 tons per year. It is estimated that 1 million such devices would be needed to capture the 1 billion tons per year stipulated in the conditions of the prize offered by Mr. Branson. The process uses proprietary sorbents to capture carbon dioxide molecules from free-flowing air and release those molecules as a pure stream of carbon dioxide for sequestration. According to GRT, one major advantage of this new technology is that it is not necessary to site the devices in immediate proximity to a major carbon source (such as a power station); for example, the CO2 emitted by traffic in Bangkok could be sequestered in Iceland by CO2 towers running on geothermal energy. Of course, the power source for the towers must not be a net CO2 producer, as this would partially offset the beneficial effects of the device. Source: physorg.com

Plastic trees

One approach that has been put forth attempts to catch carbon dioxide with artificial trees. The plastic trees are coated with a carbon-catching agent, allowing the carbon to be safely captured and sequestered, though the approach does have its limitations.

Energy Islands through OTEC

In the article Energy Island: unlocking the potential of the ocean as a renewable power source Ocean Thermal Energy Conversion is discussed as a process that uses the temperature difference between surface and deep-sea water to generate electricity – and though it has an efficiency of just 1-3% - researchers believe an OTEC power plant could deliver up to 250MW of clean power, equivalent to one eighth of a large nuclear power plant, or one quarter of an average fossil fuel power plant. Architect and engineer Dominic Michaelis and his son Alex, along with Trevor Cooper-Chadwick of Southampton University are developing the concept with plans of putting the theory to the test on an unprecedented scale by building a floating, hexagonal Energy Island that will harness energy from OTEC, as well as from winds, sea currents, waves, and the sun. The OTEC technology is something of a green dream; not only is it clean and renewable, but so are its by-products. By subjecting the steam to electrolysis, large quantities of hydrogen can be produced, paving the way for cheaper hydrogen fuel cells. And by using an Open-cycle OTEC - where low-pressure containers boil seawater and condense the steam elsewhere after passing it through the turbo-generator – large amounts of fresh water can be created. Energy Island is also packed to the brim with other renewable energy collectors, with wind, wave, current and solar sources providing a total of 73.75 MW.

Architect and engineer Dominic Michaelis estimates it would take a chain of 4-8 Energy Islands to achieve the production levels of a nuclear power plant. To replace nuclear power entirely, Michaelis estimates a chain of 3708 modules would be required, stretched over a total length of 1928 kilometres, and consuming a total square area of roughly 30 by 30 kilometres. To shoulder the entire global energy consumption, based on 2000 figures, 52 971 Energy Islands would be needed, occupying a total area of 111 x 111 kilometres - described on the Energy Island site as “a pin point in the oceans.” (http://www.gizmag.com/energy-island-otec/8714/)

From http://en.wikipedia.org/