day per person. In a power station performing carbon capture and storage,
this sustainable approach to UK coal would yield 0.7 kWh(e) per day per

Our conclusion is clear:

Clean coal is only a stop-gap.

If we do develop “clean coal” technology in order to reduce greenhouse
gas emissions, we must be careful, while patting ourselves on the back, to
do the accounting honestly. The coal-burning process releases greenhouse
gases not only at the power station but also at the coal mine. Coal-mining
tends to release methane, carbon monoxide, and carbon dioxide, both di-
rectly from the coal seams as they are exposed, and subsequently from
discarded shales and mudstones; for an ordinary coal power station, these
coal-mine emissions bump up the greenhouse gas footprint by about 2%,
so for a “clean” coal power station, these emissions may have some impact
on the accounts. There’s a similar accounting problem with natural gas:
if, say, 5% of the natural gas leaks out along the journey from hole in the
ground to power station, then this accidental methane pollution is equiva-
lent (in greenhouse effect) to a 40% boost in the carbon dioxide released at
the power station.

New coal technologies

Stanford-based company are developing the Direct Car-
bon Fuel Cell
, which converts fuel and air directly to electricity and CO2,
without involving any water or steam turbines. They claim that this way of
generating electricity from coal is twice as efficient as the standard power

When’s the end of business as usual?

The economist Jevons did a simple calculation in 1865. People were dis-
cussing how long British coal would last. They tended to answer this question
by dividing the estimated coal remaining by the rate of coal consumption,
getting answers like “1000 years.” But, Jevons said, consumption is
not constant. It’s been doubling every 20 years, and “progress” would have
it continue to do so. So “reserves divided by consumption-rate” gives the
wrong answer.

Instead, Jevons extrapolated the exponentially-growing consumption,
calculating the time by which the total amount consumed would exceed
the estimated reserves. This was a much shorter time. Jevons was not
assuming that consumption would actually continue to grow at the same
rate; rather he was making the point that growth was not sustainable.
His calculation estimated for his British readership the inevitable limits

Figure 23.3. A caterpillar grazing on old leaves. Photo by Peter Gunn.