My column in the Times on 20 June 2013:
In the Energy Bill going through Parliament there
is allowance for generous subsidy for a huge push towards burning
wood to produce electricity. It’s already happening. Drax power
station in Yorkshire has converted one of its boilers to burn wood
pellets instead of coal; soon three of its six boilers will be
doing this and the power station will then be receiving north of
half a billion pounds a year in subsidy. By 2020, the Government
estimates, up to 11 per cent of our generating capacity will be
from burning wood.
This is a really bad idea. It will cost a fortune, worsen air
pollution, exacerbate dependency on foreign energy and increase
greenhouse gas emissions compared with burning gas and maybe even
with burning coal. All these are in direct contradiction of the
Energy Bill’s ostensible purpose. Yet “biomass” is trumpeted as a
key part of the Government’s strategy to keep the lights on and
combat climate change.
It is also a retrograde step, taking us back towards the days
when we relied on plant growth for most of our energy. According to
Tony Wrigley’s recent book, Energy and the English Industrial
Revolution, firewood provided a third of Britain’s
energy under Elizabeth I, more than draught animals, human
muscle-power, wind, water or coal. By the time of Queen Victoria,
firewood’s contribution had fallen to 0.1 per cent.
This astonishing change was key to the industrial revolution. To
sustain an industrial economy requires far more energy than can be
obtained from even the fastest-growing trees, crops or from horses.
Britain would have stagnated in the early 1800s if it had not
tapped almost inexhaustible supplies of coal to replace the need to
fell trees and grow oats for horses. By 1850 England was each year
burning coal equivalent in energy terms to the maximum output of a
forest one and a half times the country’s land area. Thanks to
coal, that deforestation could begin to be reversed. By 2000,
Britain’s forest cover had trebled since its low point in 1900.
Under the Government’s plan, biomass power stations will soon be
burning much more wood than the country can possibly produce. There
is a comforting myth out there that biomass imports are mainly
waste that would otherwise decompose: peanut husks, olive pips,
bark trimmings and the like. Actually, the bulk of the imports are
already and will continue to be of wood pellets.
It is instructive to trace these back to their origin. Reporters
for The Wall Street Journal recently found that the two pelleting plants
established in the southern US specifically to supply Drax are not
just taking waste or logs from thinned forest, but also taking logs
from cleared forest, including swamp woodlands in North Carolina
cleared by “shovel-logging” with giant bulldozers (running on
diesel). Local environmentalists are up in arms.
The logs are taken to the pelleting plants where they are dried,
chopped and pelleted, in an industrial process that emits lots of
carbon dioxide and pollutants. They are then trucked (more diesel)
to ports, loaded on ships (diesel again), offloaded at the Humber
on to (yet more diesel) trains, 40 of which arrive at Drax each
day.
Yet until recently the Government was in denial about all this
diesel. “No net emissions during production are assumed,” it said
in its 2007 Biomass Strategy. More
recently, it has admitted that the energy costs of
transporting biomass can be up to “46 per cent of the energy
generated by combustion at the power station” if shipped from
afar.
Storing the pellets is not easy. If too dry, they spontaneously
burst into flames, as happened at Tilbury last year. The Health and
Safety Executive warns that stored wood pellets also produce carbon
monoxide, which can suffocate in a confined space.
Burn the pellets and you produce smoke. The Committee on the
Medical Effects of Air Pollutants says airborne particulates kill
more people than road traffic accidents. It is no accident that the
Renewable Heat Incentive, designed to subsidise us replacing gas
boilers with wood burners for central heating, is not available in
cities because it could break air-quality limits. To put it more
bluntly, your Government has decided that there is not enough
pollution in the countryside.
Moreover, soot — or “black carbon” as scientists now call it —
has recently been shown to have a much bigger impact on climate
than previously thought. “Global atmospheric absorption
attributable to black carbon is too low in many models and should
be increased by a factor of almost 3,” reads the key paper published this month.
Because burning gas does not produce soot, this is another black
mark against wood.
As for carbon dioxide, clear-felling a forest is like raiding
the carbon bank. Wood is the most carbon-rich fuel of all — more so
than coal and much more so than oil or gas. The biomass industry
and the Government respond that trees regrow, so reabsorbing from
the atmosphere the CO2 emitted when they were burnt. The
Government’s 2012 UK Bioenergy Strategy says that
wood burning “results in lower total GHG [greenhouse gas] emissions
than leaving the wood unharvested”.
But it only achieves this result by measuring the effect over
100 years. That’s how long it takes on average for the forest to
regrow. And this assumes that you do not then cut it down again, or
you are back to square one.
Over 20 or 40 years, study after study shows that wood burning
is far worse than gas, and worse even than coal, in terms of its
greenhouse gas emissions. The effect on forest soil, especially if
it is peaty, only exacerbates the disparity. The peat dries out and
oxidises.
Yet the Government persists in regarding biomass burning as
zero-carbon and therefore deserving of subsidy. It does so by the
Orwellian feat of defining sustainability as a 60 per cent
reduction in emissions from fossil fuels. As Calor Gas puts it:
“This is a logical somersault too far, conveniently — for the sake
of cherry-picking the technology — equating 40 per cent to 0 per
cent.” (Calor Gas supplies rural gas and is understandably miffed
at being punitively treated while a higher- carbon rival industry
is subsidised. See here, here and here) Moreover, unlike gas or coal, you are
pinching nature’s lunch when you cut down trees. Unfelled, the
trees would feed beetles, woodpeckers, fungi and all sorts of other
wildlife when they died, let alone when they lived. Nothing eats
coal.
So, compared with gas, the biomass dash is bad for the climate,
bad for energy security and dependence on imports, bad for human
health, bad for wildlife and very bad for the economy. Apart from
that, what’s not to like?
Postscript: For those who objected to my comment that wood
produces more carbon dioxide than coal, please see the following
short note from the Partnership for Policy Integrity
(http://www.pfpi.net/carbon-emissions):
“Burning biomass emits more CO2 than fossil
fuels per megawatt energy generated:
1. Wood inherently emits more carbon per Btu than
other fuels
-
Natural
gas: 117.8 lb CO2/mmbtu -
Bituminous
coal: 205.3 lb CO2/mmbtu -
Wood:
213 lb CO2/mmbtu (bone dry)
2. Wood is often wet and dirty, which degrades heating
value Typical moisture content of wood is 45 – 50%, which means its
btu content per pound is about half that of bone dry wood. Before
“useful” energy can be derived from burning wood, some of the
wood’s btu’s are required to evaporate all that water.
3. Biomass boilers operate less efficiently than fossil
fuel boilers (data from air plant permit reviews and the Energy
Information Administration)
- Utility-scale biomass boiler: 24%
- Average efficiency US coal fleet: 33%
- Average gas plant: 43%”