(John Kemp is a Reuters market analyst. The views expressed are
By John Kemp
LONDON Nov 18 Climate campaigners reserve a
special scorn for coal-fired power generation. Coal has replaced
nuclear as the form of energy that environmentalists most love
"The world needs to turn its back on the fossil fuels of the
past, like coal, which have helped to create today's climate and
instead look to the clean, renewable energy sources of the
future," the UK charity Christian Aid said on Monday.
"If we are to avoid dangerous climate change we must leave
most of the remaining coal reserves in the ground," the charity
Christian Aid branded the decision to host a meeting of coal
producers in Poland at the same time as the UN climate summit in
THE WAR ON COAL
Governments have been less dogmatic. But at least in the
advanced economies, policymakers see little positive role for
coal-fired power generation in future if the world is to meet a
target of limiting global warming to no more than 2 degrees by
In September, the U.S. Environmental Protection Agency
issued draft regulations requiring new coal-fired plants to emit
no more than 1,100 pounds (499 kilograms) of carbon dioxide
(CO2) per megawatt-hour (MWh).
Since even the cleanest and most advanced coal plants emit
1,700 pounds per MWh, the regulations effectively ban new
coal-fired plants unless they are fitted with expensive carbon
capture and storage (CCS) systems.
On October 29, the U.S. Treasury updated its guidance for
the World Bank and other multilateral development banks
insisting they should no longer help finance new coal plants
overseas except in very limited circumstances.
And on November 14, the federally chartered Tennessee Valley
Authority, one of the largest coal-fired generators in the
United States, announced it will retire eight coal-burning units
capable of generating more than 3 gigawatts (GW) because it was
too costly to upgrade them to meet environmental requirements.
Coal supporters, such as West Virginia Senator Joe Manchin,
have accused the Obama administration of waging a "war on coal".
The president's commitment to an "all of the above" energy
strategy has little or no role for coal, they claim.
By contrast, coal consumption is expected to continue to
grow rapidly in emerging markets. China alone will commission
about 600 GW of new coal-fired generating units by 2030,
according to the International Energy Agency (IEA).
"Coal provided nearly half of the increase in global primary
energy over the decade to 2012," the IEA wrote in its 2013 World
"But its use has serious drawbacks, especially if
inefficient: coal is a major source of local air pollution and
as the most carbon-intensive fuel, it is the main contributor to
rising energy-related carbon dioxide emissions."
The IEA conducts little research on coal, other than CCS. It
appears to advocate phasing out coal as much as possible in
favour of cleaner-burning natural gas.
AN INFERIOR FUEL
Coal's problem is its chemistry. Natural gas is mostly
methane (CH4), which contains four hydrogen atoms for every
carbon one. When hydrogen is oxidised during combustion, it
produces harmless water vapour. Only the carbon atoms turn into
greenhouse-inducing carbon dioxide.
"By several criteria, natural gas is the premium fuel,"
Harold Schobert, emeritus professor of fuel science at
Pennsylvania State University, wrote in a recently published
book on the "Chemistry of Fossil Fuels and Biofuels" (2013).
"On an equal mass basis, combustion of natural gas liberates
more energy than any other hydrocarbon fuel. It also produces
less carbon dioxide per unit of energy. It contains no inorganic
ash-forming components, so leaves no residue," Schobert
By contrast, the carbon content of coal ranges from 65
percent in the case of brown coal to as much as much as 91
percent for anthracite. Naturally, when all that carbon is
combusted it produces far more carbon dioxide. Coal also
contains numerous other impurities which form ash and
By molecular structure, the ratio of hydrogen to carbon
atoms in coal averages just 0.75:1 compared with 4:1 in the case
Natural gas has a calorific value of around 56 million
joules per kilogram, compared with 46 million for petroleum
products, and 37 million for coal. Some coals average just 28-32
million joules per kilogram.
KICKING THE HABIT
If coal is disadvantaged by its chemistry, it has other
advantages which more than make up for its lower energy content
and greater emissions.
Global reserves amount to 1,000 billion tonnes. On an
energy-equivalent basis, coal reserves are nearly as large as
gas, and almost 50 percent bigger than oil. Known coal reserves
are enough to provide energy for hundreds of years into the
For power producers, coal is often the "predominant fuel
choice because it is a secure and low-cost energy source, and
because coal resources are abundant and broadly distributed
geographically. Coal is also relatively easy to mine, ship and
store," according to the IEA's Coal Industry Advisory Board
("21st Century Coal" 2013).
"Coal remains the fastest growing source of fossil fuel,
adding more to the absolute world energy supply in the last
decade than almost all other forms of energy combined," the
IEA's industry advisors noted.
Most of the growth has come from China, India and South-East
Asia, where electricity demand is surging and domestic coal
production provides a measure of energy independence, lessening
their reliance on imported natural gas and oil.
In 2012, the IEA warned that more than two-thirds of the
currently known fossil fuel reserves will have to remain in the
ground, unburned, through 2050 if there is to be any chance of
limiting global warming to 2 degrees.
Climate campaigners have begun a disinvestment campaign to
persuade investors to boycott energy companies whose business
model relies on commercialising fossil fuel reserves.
The Carbon Tracker Initiative in Britain and Bill McKibben's
350.org in the United States have sought to emphasise the
long-term risks of investing in fossil fuel companies. McKibben
is pressing the pension funds and endowments of U.S. cities,
universities and religious institutions to avoid owning shares
Last month, mining company BHP Billiton fought off an
attempt by an independent to secure election to its board of
directors. Ian Dunlop, a former Shell executive and past
chairman of the Australian Coal Association, warned the company
risked over-investing in developing coal assets that could never
be produced because of climate targets.
Given that coal generates far higher CO2 emissions than
either natural gas or oil, it is the top target for climate
Leaving coal reserves unburned would severely disadvantage
countries like China and India with fast-growing energy needs
but relatively few oil and gas resources of their own.
Besides, leaving coal in the ground and switching to gas
would quickly strain global gas resources and result in a sharp
rise in prices.
The pressure is to find more environmentally acceptable ways
to continue using coal. Replacing the current fleet of
coal-fired power plants with the most modern generation of
ultra-supercritical generators could cut emissions by up to 30
percent. For deeper cuts, CCS, which is not currently economic,
will be required.
Supercritical and ultra-supercritical coal-fired generators
squeeze far more energy from the same amount of coal combustion.
The first supercritical plant was installed in the 1960s and
the first ultra-supercritical one in the 1990s. But of 1,610 GW
of coal-fired generation installed globally, 77 percent still
employ subcritical steam cycles, 20 percent supercritical steam
cycles, and just 3 percent are equipped with the most modern
Since the first ultra-supercritical plant went online two
decades ago, another 570 GW of very inefficient subcritical
plants have been installed.
If power generators had all installed the most modern
designs, 60 billion tonnes of CO2 emissions would have been
avoided, roughly two years worth of manmade global warming
gases, according to the Coal Industry Advisory Board.
For the coal industry and its supporters, the challenge is
to ensure that new coal-fired generation is the most efficient
available, and provide government financial support to help CCS
For many climate campaigners, however, that is not enough.
Coal combustion should be phased out unless it can be coupled
with CCS to capture all of the resulting emissions.
The result is enormous uncertainty about the long-term
outlook for the industry.
"The magnitude of future coal demand growth hinges
critically on the actions that governments take to address these
issues, taking into account their aspirations for energy
security, affordability and improved access to modern energy,"
according to the IEA.
In 2011, the world consumed around 5.5 billion tonnes of
coal. By 2035, consumption could rise to as much as 7.8 billion
tonnes on current policies, or 6.3 billion tonnes if governments
take modest further measures to combat climate change.
However, if governments are really serious about limiting
global warming to 2 degrees, coal combustion will have to fall
to just 3.6 billion tonnes, according to the IEA.
"The wide divergence in outcomes for coal in the three
scenarios ... reflects primarily the different degrees of
stringency of the policies adopted to promote energy efficiency,
reduce greenhouse emissions and improve local air quality," the
More than any other fossil fuel, the coal industry's outlook
remains highly uncertain, and almost entirely dependent on
policy choices, which is why the fight over its future has
become so bitter.
(Editing by Jason Neely)