POWER June 2012 - 14

Cost estimates for phasing out the nuclear plants that make
up about a quarter of Germany's power generation have been
similarly elusive. RWE put the number at around €300 billion,
and state-owned investment bank KfW has said it could cost
about €250 billion by 2020. Siemens in January estimated that
the phase-out could cost between €1.4 trillion and €1.7 trillion
(US$1.8 trillion and $2.2 trillion) by 2030.
While Germany's big utilities financially hemorrhage from Germany's
decision after the Fukushima crisis in Japan to phase
out all its nuclear power plants within a decade, a heated public
debate has been incited about how to best fill the nuclear
generation gap. In early May, leading energy executives from
E.ON, RWE, and Siemens, as well as power network operators and
trade unions, told Chancellor Angela Merkel that the accelerated
nuclear exit and proposed reliance on renewables would create a
10-GW power gap.
Industry, which has criticized the German government for subsidizing
renewables instead of funding infrastructure, has also called
for more incentives to invest in flexible gas-fired power plants.
Callide Oxyfuel Carbon Capture Plant
Retrofit Moves Forward
Oxyfuel technology has been retrofitted at a 700-MW coalfired
power plant in Queensland, Australia, and is now capturing
carbon dioxide from one of the plant's six steam
boilers. The Callide Oxyfuel project is being closely watched
because-since Sweden's Vattenfall in December cancelled a
key 300-MW demonstration of oxyfuel combustion and postcombustion
at the Janschwalde power plant in Brandenburg,
Germany-it is one of only a handful of carbon capture coalfired
projects that use this technology to move past concept
to construction.
Brisbane-based CS Energy began work in 2008 to modify
one of six steam boilers at its Callide A Power Station near
Biloela to enable it to produce power in oxyfiring mode for
three years. Air Liquide built both the 660-metric ton-perday
oxygen plant and the carbon capture plant, which began
operating in March (Figure 4). The oxyfuel boiler and carbon
4. Oxygen for life. Oxyfuel systems developed by Air Liquide
were retrofitted in a 1970-built, 1998-recommissioned 30-MW steam
boiler at CS Energy's 700-MW black coal-firing Callide A power station.
With oxygen available, the boiler can be started up, first on air and
slowly moved to oxyfiring-a process where the flue gas is recycled
and mixed with oxygen to take the place of the air. The oxygen production
plant has a capacity of 660 metric tons per day at an oxygen
purity of 98%. The carbon dioxide capture plant has been designed to
produce 75 metric tons of carbon dioxide per day. This image shows
the air separation plant. Courtesy: Global CCS Institute
dioxide capture plant are expected to be fully operational
later this year.
Callide Oxyfuel Project Director Dr. Chris Spero said that the
first stage of commissioning of the plant under oxyfiring conditions
had now commenced, with the successful integration of the
oxygen production units with the coal-fired boiler. " This signals
a major step forward for the project and the demonstration of
how carbon capture technology can be integrated with existing
coal-fired power stations, " Spero said.
The technology entails two air separation units that produce
oxygen, which is mixed with a portion of exhaust gas from the
boiler and recycled back into the process. Burning coal in this
mixture results in a concentration of carbon dioxide in the final
exhaust stream, where it can be more readily separated from the
other exhaust gases in the carbon dioxide capture plant. Commissioning
was critical to ensuring all of the elements of electricity
generation and the oxyfuel and carbon dioxide capture processes
are safe and thoroughly tested, Spero said.
The construction and initial commissioning phases of the project
required more than 150 staff and contractors, who worked
more than 400,000 man-hours. The A$206 million ($131 million)
project is a joint venture between CS Energy, the Australian Coal
Association, Xstrata Coal, Schlumberger, and Japanese participants
J-POWER, Mitsui & Co. Ltd., and IHI Corp. It has so far been
awarded A$50 million from the Australian Government under the
Low Emissions Technology Demonstration Fund and A$17.5 million
from the Japanese Government. The Callide Oxyfuel Project
has also received financial support from the Queensland Government
and technical support from JCOAL.
The project began at a pilot project scale at " about one hundredth
of the size of Callide A Power Station, " CS Energy said.
Pending the outcome of the 30-MW demonstration, the second
phase of the project will include building a larger demonstration
plant that produces 150,000 tons of CO2
per year for a test period
of three to four years.
The Callide Oxyfuel Project team is now also assessing potential
geosequestration sites to the west of Biloela in the Denison
Trough. Studies have suggested that the area is ideal for storing
CO2
, as it has securely stored large volumes of gas for millions
produced at Callide A will be transported approximately 300
of years and has a very low level of seismic activity. The liquid
CO2
kilometers by truck to the Denison Trough.
CS Energy predicts the technology could be applied at commercial
scale by 2020. If the project demonstration is successful,
the next step would entail applying the technology to its existing
coal-fired power stations and actively marketing oxyfuel to power
stations in Australia and overseas.
The Callide CCS project is Australia's only large-scale effort
to develop carbon capture technology. In December 2010, the
Queensland government scrapped the planned A$4.3 billion integrated
gasification combined cycle ZeroGen project, after taxpayers
had pumped A$150 million into the initiative. The government
was advised to withdraw from ZeroGen after a report described
it as " speculative. " In October 2011, the main company behind
the ZeroGen project was placed in liquidation, confirming that
ZeroGen is officially cancelled.
TVA Begins Operation of John Sevier
CCGT Plant
The Tennessee Valley Authority (TVA) has begun commercial operation
of the natural gas-fired 880-MW John Sevier Combined
Cycle Plant, located near Rogersville, Tenn. (Figure 5). Built
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POWER June 2012

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