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Renewables - May 20

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Separating food waste is profitable, study shows

Anders Sundström, Dagens Nyheter (Stockholm).
A new study for Stockholm's Traffic Board by the Swedish Environmental Research Institute shows that collecting food waste and creating methane from it in a digester produces 20-24 times more energy than is used in collecting the food waste.
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...In Stockholm, 3.9 percent of food waste is collected. This is less than in most Swedish municipalities, far from Sweden's national goal of 35 percent, and even further from municipalities like Västerås that collect 65 percent. The right-wing coalition that governs Stockholm has the goal of increasing the collection of food waste from restaurants and other institutional kitchens from 9.5 percent to 35 percent, but it has no plans to increase the separation of household food waste. Consequently, 14 percent of the total food waste would be separated...

A new study that the Traffic Board commissioned from the Swedish Environmental Research Institute shows that increasing food waste separation is very profitable from an energy standpoint. The food waste that today is turned into gas for district heating produces 12.5 times more energy than is used in collecting and processing it. Increasing the amount of separated food waste to the coalition's goal would increase the energy return on energy invested (EROI) to 20-24. Increasing food waste separation to 35 percent would maintain the higher EROI...
(18 May 2008)
Translated from the original Swedish by contributor Carl Etnier, He writes:
In the second paragraph translated, I took the liberty of correcting what I thought was an editing mistake in article. The Swedish original reads, "The food waste that today is turned into gas instead of district heating..." That didn't make any sense to me, so I translated it, "The food waste that today is turned into gas for district heating..."

UPDATE (May 20). Reader "olssonolle" writes:
I believe there has been a misunderstanding, or rather, what Mr. Etnier interpreted as an error in the original article was in fact correct.

The food waste is (now) directly combusted with other waste in waste-fired District Heating or Combined Heat and Power plants, i.e. the food is NOT turned into gas first. The idea now is to separate the food waste and produce biogas from it, which is in fact already being done in many parts of Sweden. What is special about the Stockholm example is the idea to use under-sink garbage grinders to crush the food waste and use the sewage water system to transport it all to the biogas production facility, rather than to rely on garbage truck transports.

UPDATE (May 21) Carl Etnier writes:
Olle Olsson may understand the situation there better than I do, but his explanation is not entirely in line with the article I translated. The article said that the Green Party was promoting using the wastewater system, not that it was happening. And since the report was to the Traffic Board, I suspect it had to do with the EROI using trucks.


Burning wood: issues for the future

Martin Crawford, Agroforestry Research Trust via Transition Culture
Many environmental groups are championing wood and biomass-burning as a sustainable carbon-neutral source of energy - both for heating and electricity production - for the future. However, there are several problems with moving more towards a wood-burning economy which are not really being addressed. These are:

1. Wood burning is not carbon neutral.

2. There are serious health implications from the smoke produced from wood burning, even from ‘clean’ burners.

3. Basing home heating requirements on wood burning requires a large area of dedicated woodland managed as a fuel wood.

In terms of carbon neutrality, the burning of wood often ignores the fossil fuel used in the harvesting, preparation and transporting of wood.
(19 May 2008)
Rob Hopkins introduces the article:
One of the most essential publications to which I subscribe and which I most look forward to the arrival of is Agroforestry News, produced by the Agroforestry Research Trust. It is scholarly, always illuminating and at the same time is brims with the possibilities of an entirely different way of looking at how we could feed, house and heal ourselves. The latest issue features a fascinating article which, as someone about to install a woodstove, caught my attention, and which I thought would be sure to generate some debate here at Transition Culture. Thanks to ART for permission to reproduce it here…


Quietly, wind farms spread footprint in U.S

Carey Gillam, Reuters
... While growth in ethanol use as an alternative fuel has had a big impact on rural America, wind power has also been growing steadily for the past three years, with wind farms like this one springing up all over the windy expanse of the Great Plains and beyond.

While only 1 percent of U.S. electricity comes from wind, it is attracting so much support these days that many in the industry believe it is poised for a growth spurt.

"These are pretty heady times," said Randall Swisher, executive director of the American Wind Energy Association, which held an investment conference April 30 in Iowa that drew more than 600 attendees.

"People are finally starting to see the data about what is happening to the world's climate and that is really having an impact," said Swisher.

Last year, a record 3,100 turbines were installed across 34 U.S. states and another 2,000 turbines are now under construction from California to Massachusetts. In all, there are about more than 25,000 U.S. turbines in operation, an investment of $15 billion.
(18 May 2008)


Dr. Harry Zervos discusses "Photovoltaics Beyond Conventional Silicon"
(video)
Marc Strassman, Etopia News
Dr. Harry Zervos, Technical Analyst at the IDTechEx consultancy, talks about "Photovoltaics Beyond Conventional Silicon" and the June 17th to 18th conference of the same name in Denver, Colorado, recorded from Cambridge, England, on May 18, 2008
(19 May 2008)

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