Sunday, November 24, 2013

Carbon in atmosphere 'could warm planet for centuries'

Global warming could continue for centuries even if carbon emissions were stopped overnight.

  A diesel particulate filter captures small soot particles,preventing
 them from being expelled into the atmosphere

Carbon dioxide which is already in our atmosphere could continue warming the planet for centuries even if new emissions were entirely halted, scientists claim.

A new analysis of future carbon emission scenarios found that it may take significantly fewer emissions for global temperatures to reach unsafe levels than previously thought.
Carbon dioxide, the most important greenhouse gas, has long-term effects because it can remain in the atmosphere for centuries after it is emitted.

To understand how long its influence on global temperatures will last, scientists produced a computer model of a scenario where all carbon emissions were immediately stopped after 1,800 billion tonnes had been released into the atmosphere.

They found that 40 per cent of the carbon would be absorbed by the oceans or landmasses within 20 years of emissions ceasing, 60 per cent within 100 years and 80 per cent within 1,000 years.

The decreasing levels of carbon in the atmosphere should in theory have a cooling effect, but this would be outweighed by the fact the oceans will absorb less and less heat as time goes on.

Previous studies had suggested that global temperatures would remain steady or decline if emissions were suddenly stopped, but did not account for the declining capacity of the oceans to continue absorbing heat, the scientists claimed.

Eventually the warming effect of heat which is no longer being absorbed by the oceans and is lingering in the atmosphere will outweigh the cooling caused by declining CO2 levels, they said.
Results published in the Nature Climate Change journal suggest that after an initial century of cooling following the stoppage of emissions, the planet would then warm by 0.37C over a 400 year period.
Although the change sounds small, it is almost half the total amount of warming seen since the start of the industrial era which stands at 0.85C.

According to the Intergovernmental Panel on Climate Change, an increase of 2C or more above pre-industrial levels could result in dangerous effects on the climate system.

Experts have previously warned that to keep global temperature rises below 2C, humans must keep the total amount of carbon dioxide emitted in the industrial era below 1,000 billion tonnes, about half of which has already been released.

But the new study suggests the 2C benchmark could be reached with significantly lower carbon emissions.
Dr Thomas Frölicher of Princeton University, who led the study, said: "If our results are correct, the total carbon emissions required to stay below two degrees of warming would have to be three-quarters of previous estimates, only 750 billion tons instead of 1,000 billion tons of carbon.

"Thus, limiting the warming to two degrees would require keeping future cumulative carbon emissions below 250 billion tons, only half of the already emitted amount of 500 billion tons."

Photo credit - Nick Collins Content Courtesy - Telegraph

Monday, November 04, 2013

Pumpkin Power: Pumpkins Can Make Renewable Electricity

According to the Department of Energy: It might not be long until the 1.4 billion pounds of pumpkins we produce annually are nearly as important to our energy security as they are to Halloween!  Thanks to the pioneering work of the East Bay Municipal Utility District (EBMUD), discarded pumpkins and other food waste are used as a source of renewable electricity. I was searching through the archives at Energy.Gov and found the following totally cool story. By Amber Archangel

Pumpkin Power: Turning Food Waste into Energy


It might not be long until the 1.4 billion pounds of pumpkins we produce annually are nearly as important to our energy security as they are to Halloween!

The story is a little different in Oakland, California. Thanks to the pioneering work of the East Bay Municipal Utility District (EBMUD), discarded pumpkins and other food waste are used as a source of renewable electricity.

What Does This Project Do?
  • Oakland’s EBMUD collect food waste and uses microbes to convert it into methane gas that is burned to generate electricity.
  • The Energy Department is helping to fund the development of integrated biorefineries, industrial centers dedicated to converting plant material into biofuels and other products.

With the passing of Halloween, millions of pounds of pumpkins have turned from seasonal decorations to trash destined for compost heaps or landfills.

How is that possible? First, waste haulers gather post-consumer food waste and deliver it to EBMUD’s anaerobic digesters. Inside these giant tanks, bacteria break down the food waste and release methane gas as a byproduct. EBMUD captures this gas and uses it to generate electricity in onsite generators. A ton of food waste provides about 367 m3 of gas, and digesting 100 tons of food wastes five days a week can generate enough electricity to power 1,000 homes. Once the food waste has been digested, the remaining solids make an excellent natural fertilizer, so they can be used to get next year’s pumpkin crop started.

Discarded pumpkins and other organic waste material can be used for more than just electricity.

The Energy Department is working together with industry to develop and test integrated biorefineries, industrial centers capable of efficiently converting plant material into affordable biofuels, biopower, and other products. These projects are located around the country and use a variety of materials as feedstocks.

Two of them, Enerkem in Mississippi and INEOS Bio in Florida, use municipal solid waste as a feedstock, like EBMUD, but use a process called gasification to produce ethanol and electricity. In 2012, INEOS Bio is planning to open the Indian River County Bioenergy Center, which will produce 8,000,000 gallons of ethanol, enough to fill about 232 of the largest railroad tank cars, and 6 megawatts of electricity a year from 300 dry tons of biomass a day, including yard waste and food scraps.

In Mississippi, Enerkem is planning a biorefinery on a regional landfill. They plan to convert 300 tons of solid waste a day into ethanol, amounting to 10,000,000 gallons (290 tank cars) of ethanol per year.

The Energy Department’s partnership with these companies is helping to remove barriers to commercialization of fuel and power production from municipal solid waste, including yard and food wastes, and so it might not be long until the 1.4 billion pounds of pumpkins we produce annually are nearly as important to our energy security as they are to Halloween!
Photo credit - Matthew Loveless Content Courtesy - Energy.Gov