Out of all of our meetings in Hanoi,
the one I found the most impressive and exciting was when we met with
Do Duc Tuong to talk about biogas and gasification. Tuong works for
SNV, a Dutch sustainable development NGO which focuses on
agriculture, forestry, renewable energy and sanitation.
I have discussed biogas with some
regularity on the blog. It is generally used as a renewable source of
gas for cooking and water heaters. You can convert the biogas to
electricity but that takes a bit more work to refine the gas before
you run it through the generator. One of my hopes with this trip was
to be able to understand a biogas digester and to see at least one. I
am proud to say that by the time of this writing I have probably seen
ten already. Each one has had a slightly different design but each
are effective at its purpose: turning human and animal waste into a
renewable energy source. What I like about them the most is how basic
they are in design and maintenance. One of the problems of solar
power that I am finding is that it requires education and a bit
technical knowledge. The concept of biogas is easy to understand and
hence maintain if a problem arises.
Gasification is a
process of pyrolysis with organic material. It essentially burns
organic material (wood, brush, grass, etc) without any oxygen
creating hydrogen and carbon monoxide which you can burn as a gas.
Tuong works on the SNV renewable energy team along with four others to promote biogas and gasification. It is one of the most successful programs to date. In ten years, the team has managed to organize construction of more than 150,000 biogas systems. SNV in conjunction with the Vietnamese government also trains technicians to install and maintain biogas digesters. One of the keys to biogas proliferation is the relative low cost. A biogas system for an average Vietnamese household costs about $350 usd. This is far cheaper than PV system on your roof. Larger systems on pig farms (which are now required by the Vietnamese government to have a biogas digester) ranges from $5,000 to $10,000 usd. Tuong estimates that the period of time that money is saved by having the biogas digester installed and hence pays for itself is about three to five years depending on the level usage. The retention time, the time that takes organic matter to turn into methane, is generally three to four weeks after the initial installation. Their group in particular focuses more on biogas so he didn't know many numbers on gasification projects.
My question is: How well can biogas and
gasification catch on in the States? I think the hardest part would
be explaining that fecal matter can become a renewable source of
energy. For gasification, the forests in the west are chocked full
of brush and debris that are a huge fire hazard. If there was some
way, one could harvest that debris and use it for gasification it
would be quite effective in solving two problems. There is already research underway on this issue.
When renewable energy is concerned
there is no one silver bullet. There are many. It is this combination
of diverse, low cost, localized power systems that will help
alleviate our energy needs. Diversity is our strength and we need to
look at every technology that is suitable for each environment.
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