Tag Archives: carbon dioxide

CO2 sucker could just clean the air

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Researchers in California have produced a cheap plastic capable of removing large amounts of carbon dioxide (CO2) from the air. Down the road, the new material could enable the development of large-scale batteries and even form the basis of “artificial trees” that lower atmospheric concentrations of CO2 in an effort to stave off catastrophic climate change.

These long-term goals attracted the researchers, led by George Olah, a chemist at the University of Southern California (USC) in Los Angeles. Olah, who won the 1994 Nobel Prize in chemistry, has long envisioned future society relying primarily on fuel made from methanol, a simple liquid alcohol. As easily recoverable fossil fuels become scarce in the decades to come, he suggests that society could harvest atmospheric CO2 and combine it with hydrogen stripped from water to generate a methanol fuel for myriad uses.

Olah and his colleagues also work on making cheap, iron-based batteries that can store excess power generated by renewable energy sources and feed it into the electrical grid during times of peak demand. To function, the iron batteries grab oxygen from the air. But if even tiny amounts of CO2 get into the reaction, it kills the battery. In recent years, researchers have come up with good CO2 absorbers made from porous solids called zeolites and metal organic frameworks. But they’re expensive. So Olah and his colleagues set out to find a cheaper alternative.

They turned to polyethylenimine (PEI), a cheap polymer that is a decent CO2 absorber. But it only grabs CO2 at its surface. To boost PEI’s surface area, the USC team dissolved the polymer in a methanol solvent and spread it atop a batch of fumed silica, industrially produced porous solid made from microscopic droplets of glass fused together. When solvent evaporated, it left solid PEI with a high surface area.

When the researchers tested the new material’s CO2-grabbing abilities, they found that in humid air each gram of the material sopped up an average of 1.72 nanomoles of CO2. That’s above the 1.44 nanomoles per gram absorbed by a recent rival made from aminosilica and among the highest levels of CO2 absorption from air ever tested, the team reported in the Journal of the American Chemical Society. Once saturated with CO2, the PEI-silica combo is easy to regenerate. The CO2 floats away after polymer is heated to 85 degree Celsius. Other solid CO2 absorbers must be heated to over 800 degree Celsius to drive off the CO2.

Running on wind power

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Wind power could meet about a fifth of the world’s electricity demand within 20 years, an industry group and environmental watchdog Green-peace predicted in a new report released on October 5. The global market for wind power grew 41.7 per cent in 2009, beating average annual growth of 28.6 per cent over the past 13 years, said Steve Sawyer, secretary general of the Global Wind Energy Council (GWEC). China ranked second in the world in installed wind generating capacity in 2009 and was the largest buyer of wind technology, Sawyer told reporters at the launch of GWEC and Green-peace’s Global Wind Energy Out- look 2010 report. “We would expect China to continue to be the largest market and perhaps even be the (overall) largest market in the world by the end of this year,” he said.

The report’s “advanced scenario”— its most optimistic outlook — projects the world’s combined installed wind turbines would produce 2,600 terawatt hours (TWh) of electricity by 2020 — equal to 11.5 to 12.3 percent of power demand. By 2030, wind energy would produce 5,400 TWh — 18.8 to 21.8 per cent of the world’s power supply, the report said. The more conservative “reference” scenario based on figures from the UN’s windfarmInternational Energy Agency saw wind power triple in the next decade to cover up to 4.8 percent of electricity — equal to Europe’s current total production.

The “moderate” scenario based on current industry figures would see wind power meet up to 9.5 per cent of the world’s power demand by 2020, the report said. “For more than the last 10 years, the actual performance of the wind industry has exceeded our advanced scenario every time,” said Sawyer. Under the advanced forecast, 1.6 billion tones of carbon dioxide emissions would be saved each year, the report said. This would increase to 3.3 billion tones of CO2 saved each year by 2030. The cumulative amounts of CO2 saved would be 10 billion tones by 2020 and 34 billion tones by 2030, the report said.

How Green Is Hydroelectricity?

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Hydroelectricity is often presented as a green energy source, but how true is this? Hydro has several environmental and aesthetic drawbacks that make it less than ideal compared to the clean power provided by sources such as wind and sun.

The most visible environmental aspect of Hydroelectricity is its impact on the environment, as it requires the damming of rivers. This causes the flooding of low lying land behind the dam and while this is often not desirable, the reality is that it is just an alteration to the environment. If the dam was to remain filled with water all the time, this would have no environmental effect outside the dam area.

Why is it then that Hydroelectric installations are associated with high levels of methane production? When organic matter from plants and animals breaks down without oxygen present, methane is formed. This anaerobic process is very similar to the ones that resulted in the formation of the fossil fuels we use today.

Consider the following chain of events that unfold once the dam has been constructed.

First the land is submerged and the vegetation with it. The vegetation drowns and begins to rot. Since there is very little available oxygen, the plant material breaks down to form, among other things, methane that is absorbed by the water.

This is all normal so far, as this would occur with any permanent flooding. But a Hydroelectricity dam is usually both a power supply and an urban water source and so the water levels in the dam tend to rise and fall a great deal. In dry times the water level will drop to its lowest levels which will expose land around the edges of the water and possibly at the bottom of the dam itself.

This exposed land is ideal for growing plants and so it blooms with new life. As most dams are shallow, the amount of land exposed at the edges as the water drops can be very large. The shallower the dam, the more land is exposed annually.

After a time the rains return and the dam fills up again. The new vegetation is then also covered with water and so rots anaerobically and so more methane enters the water of the dam.

This continues year after year, resulting in a slow but steady increase in the amount of methane absorbed in the water of the dam. This is a problem because methane is not very soluble in water. When the water passes through the dam’s turbines it escapes the water and enters the atmosphere.

Methane is a dangerous greenhouse gas. It is approximately 21 times more effective at trapping heat in the atmosphere than Carbon Dioxide. This means that electricity from a Hydroelectric plant can be up to three times more polluting per energy unit than the same power from a coal or oil fired plant. This figure depends on the climate and geography the Hydro plant is located in, as these factors determining the amount of vegetation added to the dam each year. The Intergovernmental Panel on Climate Change (IPCC) has recognized this issue and now includes methane from Hydroelectricity in national emissions totals.           hydroelectricity

Hydroelectricity may be a renewable energy source but it is not an environmentally friendly one. When looking at whether a new Hydro plant is warranted, methane emissions must be taken into account. A cleaner and greener solution is to build solar and wind energy stations as once constructed these have no emissions associated with them at all.
For more information on electricity generation and its issues, visit the Fossil Fuels section of Roger Vanderlely’s website. There you can also find out about getting a good deal on cheap solar panels to become more power independent and do your bit for the environment.

This article is brought to you by George Zalcman. George Zalcman has always had a passion for green technologies, and believes that we should all get on the boat before natural resources become limited. George Zalcman is part of an air to water technology hoping that this will eventually bring an end to the water crisis as well.