Sweden takes biogas to a new level: methane from wood chips to fuel 75,000 cars
Europe is experiencing a real boom in the use of biogas for transport. According to an EU well-to-wheel study of more than 70 different (fossil and renewable) fuels and energy paths - including hydrogen from wind, solar or nuclear -, biogas is the cleanest and most climate-neutral transport fuel of them all (earlier post). Given the expectation that carbon prices will explode in the coming years, the clean green gas is attracting major investments as an alternative to fossil fuels.
The gas, which is obtained from municipal, industrial or agricultural organic waste, holds tremendous potential, both in Europe (where it can replace a large amount of natural gas imports from Russia), and in the developing world (with India having interesting plans for biogas). Using innovative technologies, the green fuel can be purified to natural gas standards, and mixed into the natural gas grid (earlier post), with several countries already doing this. Other European countries and companies are rapidly building infrastructures to use the gas as an automotive fuel (an example from Germany, and one from Austria) with some companies building real biorefineries around it which result in green specialty chemicals and products such as biopolymers and plastics (example from Austria). More and more, specially bred dedicated biogas crops - such as Sudan grass hybrids, Sorghum or biogas maize - are being planted for the production of the green fuel.
Biogas from wood chips, more efficient than cellulosic ethanol
Sweden, Europe's leader when it comes using renewables (the country generates 28% of all its energy from green sources) is now taking the development of biogas as a transport fuel a step further. Anders Hedenstedt, CEO of Göteborg Energi AB, wrote the following letter to Euractiv, a main EU news source: "In Gothenburg, biogas is produced locally by digestion of sewage waste, providing the equivalent of 4000 passenger cars with a fuel that is cleaner than petrol, or any other biofuel.
Now Göteborg Energi is taking biogas production to the next level. By gasification of low-grade biomass such as forestry residues, we can produce biogas in much greater quantities. Our aim is to build a biomass gasification plant with a capacity to produce enough biogas for 75,000 cars. We will convert wood chips into methane with 70% efficiency:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: wood :: methane :: biogas :: natural gas ::
We plan to have the plant in operation by 2011 at a cost of roughly €150 million. Since the technology employed is untested on this scale, we are depending on government or EU funding.
Public awareness of biogas as a fuel for vehicles is crucial for our success in this project. Of course, biogas could be used for many more applications than for vehicles. But we are convinced that the transport sector will play a key role as a driver of new technology, because the willingness to pay in this sector is high, and that there is a very real opportunity for consumers to individually contribute to a more sustainable society."
Several studies indicate that, using a combination of substrates (from dedicated energy crops) that are co-fermented, biogas yields much more useable energy than cellulosic ethanol. The bioconversion process is far more efficient. But the large-scale use of the green gas has one major disadvantage, in that one needs dedicated cars, similar to CNG-vehicles, to use the fuel.
More information:
Trendsetter-Europe, the information source on sustainable trends in urban mobility in the EU, has a range of interesting articles on biogas as a transport fuel.
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Thursday, December 07, 2006
Plastics are "poisoning the world's seas"
Microscopic particles of petroleum-based plastics are poisoning the oceans and may end up in the food chain, according to a British team of researchers. They report that small plastic pellets called "mermaids' tears", which are the result of industry and domestic waste, have spread across the world's seas.
The scientists had previously found the debris on UK beaches and in European waters; now they have replicated the finding on four continents. As the BBC reports, the scientists are worried that these fragments can get into the food chain.
Plastic rubbish, from drinks bottles and fishing nets to the ubiquitous carrier bag, ends up in the world's oceans. Sturdy and durable plastic does not bio-degrade, it only breaks down physically, and so persists in the environment for possibly hundreds of years:
biomass :: energy :: sustainability :: bioplastics :: biopolymers :: biodegradable :: oceans ::marine life :: food chain :: oil :: petroleum :: pollution ::
Among clumps of seaweed or flotsam washed up on the shore it is common to find mermaids' tears, small plastic pellets resembling fish eggs.
Some are the raw materials of the plastics industry spilled in transit from processing plants. Others are granules of domestic waste that have fragmented over the years.
Either way, mermaids' tears remain everywhere and are almost impossible to clean up.
Raw materials
Dr Richard Thompson at the University of Plymouth is leading research into what happens when plastic breaks down in seawater and what effect it is having on the marine environment.
He and his team set out to out to find out how small these fragments can get. So far they've identified plastic particles of around 20 microns - thinner than the diameter of a human hair.
In 2004 their groundbreaking study reported finding particles on beaches around the UK. Historical records of samples taken by ships plying routes between Britain and Iceland confirmed that the incidence of the particles had been increasing over the years.
Now the team has extended its sampling elsewhere in Europe, and to the Americas, Australia, Africa and Antarctica.
They found plastic particles smaller than grains of sand. Dr Thompson's findings estimate there are 300,000 items of plastic per sq km of sea surface, and 100,000 per sq km of seabed.
So plastic appears to be everywhere in our seas. The next task was to try and find out what kind of sea creatures might be consuming it and with what consequences.
Thompson and his team conducted experiments on three species of filter feeders in their laboratory. They looked at the barnacle, the lugworm and the common amphipod or sand-hopper, and found that all three readily ingested plastic as they fed along the seabed.
"These creatures are eaten by others along food chain," Dr Thompson explained. "It seems an inevitable consequence that it will pass along the food chain. There is the possibility that chemicals could be transferred from plastics to marine organisms."
Other contaminants
There are two ways in which this might happen. Firstly, the Plymouth scientists want to establish whether there is the potential for chemicals to leach out of degraded plastic over a larger area after the plastic has been ground down.
The second aspect of this research is focusing on what happens when plastic absorbs other contaminants.
So-called hydrophobic chemicals such as PCBs and other polymer additives accumulate on the surface of the sea and latch on to plastic debris.
"They can become magnified in concentration," said Richard Thompson, "and maybe in a different chemical environment, perhaps in the guts of organisms, those chemicals might be released."
Whether plastics present a toxic challenge to marine life and subsequently to humans is one of the biggest challenges facing marine scientists today.
The plastics industry's response is that much of the research is speculative at this stage, and that there is very little evidence that this transfer of chemicals is taking place in the wild.
It says it is doing its bit by replacing toxic materials used as stabilisers and flame retardants with less harmful substances.
Whatever the findings eventually show, there is little that can be done now to deal with the vast quantities of plastic already in our oceans. It will be there for decades to come.
Picture: correspondent Tom Heap holds examples of "mermaids' tears" - courtesy of the BBC.
More information:
University of Plymouth: Where does all the plastic go? - 7 May 2004
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posted by Biopact team at 8:09 PM 1 comments links to this post