Published: 17 Nov 2011
Carbon capture and storage (CCS) involves capturing carbon dioxide released by power stations and other industrial sources, and burying it deep underground. But in addition to keeping an important greenhouse gas (GHG) out of the atmosphere, this technology will lead to benefits and trade-offs for air pollution. A new report from the European Environment Agency (EEA) describes the effects that CCS may have on emissions of some key air pollutants.
Carbon capture and storage can bridge the gap for the next few decades, cutting emissions until we can shift to a low carbon economy. Our report shows that while CCS may have an overall positive effect on air pollution, emissions of some pollutants may increase. Understanding these types of trade-offs are extremely important if we are to deploy this technology across Europe and the world.
Professor Jacqueline McGlade EEA Executive Director
“Carbon capture and storage can bridge the gap for the next
few decades, cutting emissions until we can shift to a low carbon economy”,
Professor Jacqueline McGlade EEA Executive Director said. “Our report shows
that while CCS may have an overall positive effect on air pollution, emissions
of some pollutants may increase. Understanding these types of trade-offs are
extremely important if we are to deploy this technology across Europe and the
CCS technologies require approximately 15 – 25 % more energy
depending on the particular type of technology used, so plants with CCS need
more fuel than conventional plants. This in turn can lead to increased ‘direct
emissions’ occurring from facilities where CCS is installed, and increased ‘indirect
emissions’ caused by the extraction and transport of the additional fuel.
The EEA report identifies some of the potential benefits and
trade-offs for the main air pollutants. It also presents a life-cycle case
study for 2050 considering three different scenarios, showing the potential
impacts on emissions of air pollutants if CCS were widely implemented in
Europe. Key findings include:
dioxide (SO2) emissions from power plants are predicted to fall
when carbon dioxide (CO2) is captured, as SO2 must also
be removed after the fuel combustion stage for technical reasons. Although the extraction
and transportation of additional coal will lead to higher SO2
emissions from these stages of the CCS life-cycle, SO2 emissions
should decrease overall.
matter (PM) and nitrogen oxide (NOx)
emissions are expected to increase in line with the amount of the additional
fuel consumed if no additional measures to reduce emissions are installed.
(NH3) is the only pollutant for which a significant increase in
emissions is expected to occur, with emissions potentially increasing by a factor
of 3 or more. The foreseen increase is due to the degradation of the
amine-based solvents used to capture the CO2. However, in absolute
terms the increase is small compared to existing ammonia emissions in Europe,
94% of which comes from agriculture. Ammonia contributes to acidification and
eutrophication of the environment and also can form harmful fine particulate
matter when released in the atmosphere.
- Potential carbon
dioxide (CO2) savings from CCS vary greatly across the three
scenarios in the report. Emissions of CO2 in the EU would fall by around
60 % by 2050 if CCS were implemented at all coal-based power generation plants.
Implementing CCS at all coal, gas and biomass plants would result in net
negative emissions – in effect removing CO2 from the atmosphere.
This assumes that all biomass is harvested sustainably without any net changes
to the carbon stock.
- The case study also shows clearly that the extraction
and transport of additional coal can contribute significantly to the life-cycle
emissions for coal-based CO2 capture technologies. Overall, however, CCS is considered to be
generally beneficial both in terms of climate change and air pollution. However,
the potential increase in certain pollutants such as NH3, NOx
and PM is important.
Carbon capture and storage
technologies are assumed to play a central role in helping Europe achieve its
long-term GHG reduction objectives in a cost-effective way, reducing domestic
GHG emissions by 80-95 % by 2050. Implementing CCS is therefore
considered as a bridging technology, and should not introduce barriers or
delays to the EU’s objectives of moving toward a lower-energy and
more resource-efficient economy.
In the EU, there are plans to
build several demonstration plants for CO2 capture and storage in
order to commercialise the technology from 2020. Currently, there are around 80
large scale CCS projects at various stages of development around the world but
only a few are operational. There are as yet no large-scale CCS plants in operation
which cover all three elements of the CCS chain – the capture, transport and
storage of CO2.