[Gasification] Charcoal Gasifier No 2.

[Ken Boak]

Bob & List,

The first part of this is OFF TOPIC - but please bear with me.  It is a 
classic example of what can happen when renewable energy products are sold 
in retail outlets.

Small windturbines in the <1000W rating enjoyed a brief commercial hype in 
the UK, but were quickly deemed unfit for purpose.  This mirrored the same 
series of events which happened in the US a few years previously.

The main reason is that they required considerably more wind speed than was 
available in most urban areas, and their average output was often about 
1/8th of that quoted - because the mean wind speed was half of that quoted 
by official figures.

Addditionally the grid tied inverter supplied with the turbine had an 
overhead net draw of about 50kWh per year from the grid to power its 
internal electronics, interlocks etc.

As a result, many were finding that their $3000 roof mounted turbines were 
underperforming considerably and even costing them electricity.  This 
situation has led to a knock-on effect of low consumer confidence in 
windpower.

Renewable energy schemes tend to work better when you have the economy of 
scale,  i.e large wind farms,  large solar arrays in the dessert, large 
hydroelectric projects.  The same is probably true for gasification 
schemes - likely these need to exceed 1MW in capacity before they can be 
viable commercially.

The idea of a 10MW gasification plant that burns municipal waste, 
construction waste, tree surgery prunings etc and supports 10,000 houses is 
probably the minimum size that would be viable.

There are lessons to be learned from the past - Britain was once almost 
exclusively heated by coal fires, and all household waste was put on the 
fire.  10 million individual coal fires in the high density populated areas 
gave rise to a lot of atmospheric pollution and associated respiratory 
diseases.

Now Britain is extensively heated by gas, and these polllution problems have 
been vastly reduced,  However, recent hikes in gas prices have motivated the 
UK to purchase woodstoves, often Chinese manufactured and often badly 
installed resulting in greater levels of urban smoke levels.  Might not a 
return by individuals to using gasifying wood fired boilers, might lead to 
additional airpollution with tars and other carcinogens?

We should also not forget the historical situation in China, when in Mao's 
attempt to boost steel production, his administration encouraged the use of 
"backyard blast furnaces".  Very little usable steel was produced but 
millions of rural poor faced starvation.



Ken