Wind and biomass are cheaper than carbon sequestration
CANBERRA, Australia, 2004-10-06 (Refocus Weekly)
Renewable energy is much less expensive than storing carbon in the ground, according to a report published by the Australia Institute think tank.
Australia uses coal to generate 80% of its electricity and those power plants
emit 30% of the country’s total GHG emissions, explains Hugh Saddler in
‘Geosequestration: What is it and how much can it contribute to a sustainable
energy policy for Australia?’ Oil and natural gas companies are investigating
geosequestration as a solution to CO2 emissions, including a large-scale trial
at a gas field in the Norwegian sector of the North Sea.
Geosequestration involves injecting CO2 into underground geological formations
where it would be stored for hundreds of years. Recent proposals by the
Australian government to use geosequestration to reduce GHG emissions to a small
fraction of their present level, while allowing continued combustion of coal,
“has great superficial appeal,” concedes the discussion paper. “The
reality is that Australia will continue to rely on fossil fuels for the bulk of
its expanding power requirements, for as long as the reserves last,” but there
are other options.
CO2 capture & storage (CCS) from existing power stations would require
“large and expensive equipment and use large amounts of energy, thereby
reducing overall power station efficiency,” and research has started on new
coal utilization technologies to reduce the cost and complexity of capturing
CO2, such as integrated gasification combined cycle and oxy- fuel combustion.
Transport of CO2 is relatively energy intensive and will require large
investments in pipeline infrastructure.
The paper examines the capital and operating costs of a CCS system and its
overall thermodynamic efficiency of supplying electricity, as well as the
ultimate level of emissions and the large uncertainty in the cost of CCS, “it
is clear that coal-fired generation with CCS will be more costly than a number
of other low-emission electricity generation options” including wind, many
types of biomass and gas-fired cogeneration.
“All these technologies are far more mature than CCS; they are proven, already
in widespread commercial use but, also, particularly in the case of wind, likely
to fall considerably in cost over time as further experience with the
technologies is gained,” it concludes. When the costs of abatement are
considered, wind, biomass, energy efficiency and natural gas “are more
economically attractive than CCS as abatement options.”
“It is difficult to see how coal-fired power stations, with the additional
cost of CCS, will be able to compete with the alternative means of cutting
emissions, at least for some decades,” and the report says it does not examine
the environmental risks that CO2 may escape from storage sites.
“If gas-fired generation and renewable energy were built instead of new
coal-fired generation, to achieve the same cumulative abatement by 2030 as CCS
would require only a doubling of the current very modest MRET target,” it
concludes. “Scenarios that include more extensive energy efficiency
improvements, though still well within identified technical potential, combined
with use of gas-fired generation and renewables instead of new coal-fired plant,
could reduce emissions in 2030 by more than five times as much as CCS alone, and
cumulative emissions by ten times as much.”
The use of CCS alone would reduce emissions by 9% in 2030, and cumulative
emissions from 2005 to 2030 by only 2.4%, but modestly-increased energy
efficiency could reduce emissions in 2030 by the same amount and cumulative
emissions by twice as much, but at “zero or even negative cost.”
The key to these results is that wind, biomass, end-use efficiency and gas-fired
generation are currently commercially available, and do not have to wait until
2020, although the paper concedes that CCS may be an effective abatement option
after 2030.
“For the foreseeable future, end-use efficiency, gas-fired generation and wind
will continue to have lower costs than coal-fired generation with CCS,” it
says. “A policy that neglects or excludes other low-emission technologies, in
favour of coal with CCS, will place Australia on an unnecessary high-cost path
to reducing emissions. This is not an economically optimal policy for reducing
GHG emissions from the energy sector.”
CO2 emissions from renewable energy technologies, including wind, bioenergy,
hydroelectricity and solar, “are close to zero during operation, although
there may be lifecycle emissions if non-renewable energy is used during
manufacture,” it explains. One estimate of a 5 MW windfarm in Australia said
life-cycle emissions would be 12.2 kg CO2-e/MWh.
Click
here for more info...
Visit http://www.sparksdata.co.uk/refocus/ for your international energy focus!!
|