ion of wood is a simple technology that introduces secondary air to the falling ash which superheats it and combusts the ash and wood smoke to a point where there is very little left. The process is extremely efficient and gets the most energy out of a log of wood whilst leaving little ash to clean out.
Gasification is a process for burning wood where the gases from the wood are burned at very high temperatures, and although it was used extensively 50 to 100 years ago, since the advent of cheap oil in the late 1950s and 1960s it has been largely ignored.
Gasification works both at a very simple level in wood stoves and in huge gen stations feed megawatts of power into national electricity grids. For some time the big generators like GE have recognised this and have been developing the highly technologically sophisticated Integrated Gasification Combined Cycle (IGCC) Generator, since multi-millions of dollars into the idea.
However, until very recently society had forgotten the fact that gasification can also be sued at the domestic stove level and bring big efficieny and smoke emissions reduction benefits at the same time.
In a simple wood gasifier ingenious design (or a small electric fan in many designs) causes a downdraft which produces extreme heat up to 2000 degrees igniting all gases including smoke and creosote therefore giving almost 100% efficiency. The gasification effect works by way of the downdraft that sucks wood gas from the firebox in the top chamber down into a bottom chamber where superheated combustion occurs.
Biomass gasification extend the idea from wood stoves, where there are a number of products now on the market inot using a huge range of available fuels, not just wood. In its current state the use of biomass, is open-source and grassroots. Many people are cobbling together gasifiers and they are normal Joe’s and Jane’s. What you or I would call backyard tinkerers! But, we should all be grateful to them because this technology needs wrestling away from the boffins and the multi-millions dollar corporations. It is just too important for the health of the planet that at all levels society uses the renewable energy freely availabe to us, to its fullest.
Biomass gasification projects could be of interest under the CDM (Carbon Discharge Management – or carbon Credits within the scheme dreamt up at the Kyoto summit years ago) because the renewable biomass energy used directly displaces greenhouse gas emissions while contributing to sustainable rural development.
However, amazingly until recently there was only one biomass gasifier project registered under the CDM as yet, among thousands of other schemes.
Biomass gasification is a renewable, low cost and environmentally friendly energy alternative to using carbonaceous fuels like oil and coal or natural gas. Biomass energy has evolved since its first applications, but in general the sad fact is that until now it has not been possible to reach a solid commercial stage, except during periods of crises and only for some specific applications.
Meanwhile, other gasification technologies, fed by fossil fuels, have received big invetsment and are currently widely used on industrial scales, for example in refineries enabling poor quality and even waste oils which traditional refineries have no use for to be utilized.
Biomass gasification certainly works, and it worked 20 years ago. It is just been seen as a capital-intensive process that has the problem of competing against lower cost (but unsustainable) gasification options, and too complex to be used in the small scale.
Now at least the back garage tinkerers have gasifiers under development which will with their inspired skills and ability to innovate, have every prospect of rescuing this technology from the boffins by producing small cheap and amazingly efficient boilers using all sorts of fuels at present unused and wasted.
For my money I say three cheers for these guys and girls not afraid to get their hands dirty, roll up their sleeves and make so much more than any stove which can make tea!
Steve Evans is an anaerobic digestion biogas energy enthusiast. Far from being despondent about rising gas prices he sees it as a great opportunity for us to start using the clean wind energy which is available all around us without harming our planet.
