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Microalgae Carbon Capture
A new ground breaking technique of Carbon Capture has been developed by a Chinese firm, ENN. They have created a bioreactor that breeds micro-algae, one of the fastest growing organisms on the planet, using carbon captured from gasified coal. This may be the way forward to absorb carbon emissions and reduce its effects on climate change.
China is the world's biggest emitter of greenhouse gases and is currently building more than one new 500MW coal-fired plant every week and likely to be dependent on coal for at least two decades. The carbon emissions mainly come from coal fuelled power stations which supply 70% of China’s power. Almost none of the carbon dioxide is captured, partly because there is no profitable way of using it.
Carbon Capture is one of three main techniques used for preventing carbon dioxide from coal-fired power stations contributing to global warming. Carbon capture and storage encompasses a range of technologies. Together they hold the promise of trapping up to 90% of the carbon dioxide emissions from power stations and industrial sites. Current techniques involve collecting, transporting and then burying the CO2 so that it does not escape into the atmosphere and contribute to climate change.
Once the CO2 has been trapped, it is liquefied, transported – sometimes over several hundred miles – and buried, either in suitable geological formations, deep underground saline aquifers or disused oil fields. These technologies are not cheap as up to 40% of a power station's energy may be needed to run the Carbon Capture and Storage systems. In Britain experts estimate the average cost of retro-fitting Britain's aged power stations at about £1 billion each. Additionally, pipes to transport the CO2 to suitable burial sites could cost £1 million per mile. Thus some power stations may be uneconomical to refit.
Algae may be the answer to carbon emissions in China and the rest of the world. Micro-algae can absorb carbon dioxide far more quickly than trees and this attribute has long attracted scientists seeking a natural method of capturing carbon dioxide.
At ENN's research campus in Langfang, scientists are testing different types of micro-algae to clean up wastes from burning coal. The micro-algae passes through a greenhouse filled with transparent pipes multiplying rapidly as it flows through tubes, stacked 14 high in four long rows.
Carbon Capture involves a series of steps. First, coal is gasified in a simulated underground environment, then carbon dioxide is extracted using solar and wind power and finally it is "fed" to algae encouraging their multiplication and growth. The algae can then be harvested daily and used to make bio-fuel, fertiliser or animal feed.
Over the next three years, researchers at the algae greenhouse plan to scale up the trial to a 100 hectare (247 acre) site. If this proves commercially feasible, coal plants around the world could one day be using carbon-cleaning algae greenhouses or ponds.
"Algae's promise is that its population doubles every few hours. It makes far more efficient use of sunlight than plants," said Zhu Zhenqi, a senior advisor on the project. "The biology has been proven in the lab. The challenge now is an engineering one: We need to increase production and reduce cost. If we can solve this challenge, we can deal with carbon."
Some consider that this might work on a large scale where land is cheap, plentiful and in need of fertiliser but that elsewhere, application may be limited because of the large areas of land or water needed for micro-algae cultivation. ENN is considering two sites for its 100 hectare test facility. The first site is near the company's 600,000 tonne-a-year coal mine in Ordos, Inner Mongolia, because of cold winters micro-algae will require a heated greenhouse. The second location is further away from China's main coal deposits on Hainan Island, where the hot weather would allow the algae to be grown more cheaply in open ponds.
According to Ming Sung, Chief Representative for Asia Pacific of Clean Air Task Force "Algae is not likely to be the main solution for the carbon problem because of the huge amount of CO2 that needs to be consumed but algae is part of the solution and is closer to what nature intends. Being one of the simplest forms of life, all it takes is light and CO2 in salt water."
Algal Carbon Capture is taking off in other locations around the globe. In May 2009 the Obama Administration provided $2.4 billion in Funding for Carbon Capture and Storage Projects including research into carbon capture using algae. Algae tests are also being carried out at the University of Ohio. And in Japan, algae is farmed at sea where it absorbs carbon from the air. So, in the future algae may help to reduce carbon emissions and reduce climate change. What are your thoughts? Have your say. We welcome your thoughts and proposals. Add your comment below. Have your say. We welcome your thoughts and proposals. Add your comment below. Not a Citizen? Sign up
In last 100 years 150 gigatons of carbon from fossile fuel have been added to the earth's atmosphere. Use of the natural algae-carbon cycle to refossilze co2 mitigation of 5-10 gigatons of carbon annually will be necessary through large scale phytomass production system.Treerstrial system are limited to 2-3 megatons of carbon uptake per year and may not sequester this carbon for period of centuries. we need large scale oceanic based carbon absorption, sequestering and displacement system. Open ocean macro algal farms have to come up for this to dissipate very high quantity of energy.
