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What are we doing about it?
Climate change is a global problem that needs global solutions. Leading scientists and governments have identified that worldwide CO2 emissions must be drastically reduced in order to lessen the effects of climate change. The UK Government has realised the threat of climate change to both the UK economy and the global population, and has therefore agreed to drastically reduce CO2 emissions by 2050, to 60% of 1990 levels. This does however lead to a technological challenge. 75% of the UK's electricity is currently generated by fossil fuel power plants and renewable energy still needs further development time to make it an affordable and relibable source of electricity.
Carbon Capture and Storage (CCS for short) is a technology that allows us to still use fossil fuel energy whilst renewable energy is further developed to enable it to provide our electricity. CCS involves capturing CO2 from fossil fuelled powered stations and storing the CO2 underground instead of releasing back into the atmosphere. We will therefore be able to reduce our CO2 emissions significantly, lessen the impact of climate change on our environment and give the world breathing space whilst renewable energy technology is developed.
CCS technology can be broken down into four stages:
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1. Capture
CO2 is most effectively captured from sites where it is being emitted in large amounts into the atmosphere e.g. coal and gas fired power stations. There are a variety of ways to do this. One way is to capture the CO2 fumes of a power plant - similar to catching the exhaust fumes from a car. CO2 capture has been before and is a common industrial process. [ More.. ] |
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2. Transport
After capturing the CO2 gas, it is then pressurised and changed into a liquid to allow for ease of transport. It is much easier to transport liquid over long distance than to transport gas. The liquefied CO2 can be transported via road, tanker boats, or more cheaply by special CO2 pipelines just like natural gas is pumped to homes. The CO2 can be transported tens or hundreds of kilometres to a storage site either an onshore (on land) or off shore (under water) storage site. [ More.. ] |
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3. Storage Once it arrives at the storage site, this liquid CO2 is injected into the ground through a well. Places were gas and oil used to be (before it was mined out) are perfect places to store CO2. If these places had previously held oil and gas for millions of years, then it is a possibility that they could be used as storage sites once again and store the CO2 that we have taken from the power stations. There aren't just big holes under the ground that the CO2 is being injected into. The oil and gas...and soon the CO2 were stored in the pore spaces between the grains of rocks. It doesn't look like it, but there is a lot of space between the grains of something like a sandstone. You could imagine the reservoir like a really big sponge. Sponges take up a lot of space but they can also hold lots of water in them. On top of our sponge, or reservoir, we have something called a cap rock. The cap rock acts as a type of 'lid' to the sponge and traps all the CO2 in the reservor. The cap rock is made out of a different rock than our reservoir rock. It is made out of a type of rock that is relatively impermeable, which means that it is hard for anything to pass through it. Shale is a good example of a cap rock. [ More.. ] |
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4. Monitoring Monitoring and verifying the quantities of CO2 stored is essential if CO2 storage is to be used to meet national or international commitments on reducing emissions or as a basis for emissions trading. Any CO2 storage options would also need to verify that there is no leakage of CO2 from the storage reservoir. During CO2 capture flows of gas would be measured as a normal part of the capture process. In a similar fashion large CO2 pipelines in the USA constantly monitor large quantities of CO2 and similar methods could be used to monitor CO2 injected into geological storage sites. [ More.. ] |