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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorTomN
    • CommentTimeMay 31st 2007
    When are these fuel cells going to start appearing?

    I know that there are a few token ones dotted around the place and a search on the internet seems to show that there are dozens of companies that have units in development but they are taking too long!

    Does anyone know of any units that are available for private homes (~3kWe)?
    The last report that I read (Jan 2007) suggested that they will be ready for reliable widespread domestic use in 15-25 years.
    What a useless duplication of infrastructure. Where is the fuel going to come from to power the fuel cells? The reason electricity generation was centralized in the first place was econmy of scale. All this micro-generation talk is just so wasteful of resources IMHO. Gosh how quickly we forget the lessons of history.

    Paul in Montreal.
    Which lessons did you have in mind, Paul?
    • CommentAuthorTomN
    • CommentTimeMay 31st 2007

    What about if you have a means of producing hydrogen locally, whether through PV or wind power? The hydrogen could then be stored for use in the fuel cell when there is a demand and maybe even for your car.
    I saw a comment in something I was reading yesterday that said most fuel cells need platinum as a catalyst to work and there is no substitute for this. It also said scientists estimate that the world be be out of platinum in 15 years at current usage and we are not recovering any of the stuff we are currently using, for example, in catalytic converters for diesel cars, which again need platinum - nothing else will do. I wouldn't hold your breath waiting for fuel cells to become available to the mass market. Which ever way you look at the problem we are bumping up against limits to growth. The only way is to use less energy energy.
    Posted By: Mark BrinkleyWhich lessons did you have in mind, Paul?

    The general lesson being that acting collectively is usually more beneficial in the long term than acting individually.

    All this talk about micro generation is just the tip of the iceberg, IMHO, as people want to become isolated from the rest of society. Whilst some of the goals may be laudable, I really question how effective this kind of "me first" action really is.

    It was through the collectivisation of infrastructure in Victorian times that allowed the progress to the modern society we have now. Of course, one could argue that we'd all be better off if we'd stayed largely agrarian but we're stuck with the reality that we have.

    I think our efforts are better spent at finding widely applicable solutions that benefit everyone, as well as individually trying to reduce our consumption of all resources, not just energy. Unfortunately, the capitalist economy we live in is predicated on consumption and continuous growth. It astounds me that no-one seems to talk seriously about reducing growth to zero or, shock, moving to negative growth. The message that seems to be heard the loudest (especially here in North America) is that it is one's duty as a citizen to continue consuming "for the sake of the economy".

    All in my humble opinion of course.

    Paul in Montreal.
    Posted By: TomNWhat about if you have a means of producing hydrogen locally, whether through PV or wind power? The hydrogen could then be stored for use in the fuel cell when there is a demand and maybe even for your car.

    This sounds good in theory, as it avoids all the transportation issues and does provide storage to address the demand versus production problems of PV systems.

    However, fuel cells are just not very efficient. From the wikipedia entry:

    For a fuel cell operated on air (rather than bottled oxygen), losses due to the air supply system must also be taken into account. This refers to the pressurization of the air and adding moisture to it. This reduces the efficiency significantly and brings it near to the efficiency of a compression ignition engine. Furthermore fuel cells have lower efficiencies at higher loads. It is also important to take losses due to production, transportation, and storage into account. Fuel cell vehicles running on compressed hydrogen may have a power-plant-to-wheel efficiency of 22% if the hydrogen is stored as high-pressure gas, and 17% if it is stored as liquid hydrogen.[8]

    Fuel cells cannot store energy like a battery, but in some applications, such as stand-alone power plants based on discontinuous sources such as solar or wind power, they are combined with electrolyzers and storage systems to form an energy storage system. The overall efficiency (electricity to hydrogen and back to electricity) of such plants (known as round-trip efficiency) is between 30 and 50%, depending on conditions.[9] While a much cheaper lead-acid battery might return about 90%, the electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore better suited for long-term storage.

    It sounds to me, at the moment, that local storage is more efficient with batteries than the conversion to hydrogen and then back to electricity. For those nervous of large lead-acid accumulators, flywheel-based storage is a great alternative and is already used in large UPS systems where the presence of hydrogen from accumulator venting would be a problem.

    Paul in Montreal.
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