Carbon Capture and Storage
11-06-08
Under Europe's Climate and Energy Package of new legislation, there has been a growing recognition of the need to "clean" the use of fossil fuels in power generation, to remove the carbon emissions for storage, so that it does not enter the atmosphere.
This technology - called carbon capture and storage (CCS) - is at a very early stage, with no commercial-scale plants yet built, only a handful of small-scale projects.
CCS is being fostered at a European level by a new Directive and a demonstration programme. The Directive should set the ground rules on how best to go about capturing and storing carbon dioxide, while the demonstration programme aims to ensure the technology works before it goes ahead on a larger scale.
At an EU level, work is being focussed on capturing carbon from coal power, which accounts for around 24% of European energy and generally has the highest carbon emissions of any fuel.
One downside of CCS is that it is said to increase fuel use in coal power stations by between 10% and 40%. But, it is believed that CCS can capture at least 90% of emissions from the combustion of coal.
Predictions are that coal power will grow by 70% up to 2030, particularly with gas supplies dwindling in the North Sea, with global reserves controlled by nationalised companies subject to potentially difficult geopolitics.
The UN Climate Change panel predicts that up to half of all carbon emission cuts required to slow climate change will come through CCS. But, to meet global emission targets some 620 CCS plants would have to be operational by 2030 according to the UK government.
The clock is ticking with EU climate change targets set for the year 2020, and with predictions of limiting the rise in global temperatures to two degrees centigrade based on CCS being in operation commercially by 2015-2020.
CCS Directive
CCS technology
There are three main types of CCS technology at present:
- Pre-combustion – carbon dioxide is removed before the fossil fuel is burned, such as through gasification, where crushed coal is heated to produce a "syngas" separated into energy-rich hydrogen and carbon dioxide to be stored.
- Post-combustion – carbon dioxide is separated from flue gas and emissions from the burning of fossil fuels, before being stored.
- Oxyfuel – pure oxygen is added to the combustion of fossil fuel, which then supposedly makes it easier to remove the carbon dioxide after combustion.
The original proposal for a CCS Directive was not to make the technology compulsory for coal power plants, but to break down the legislative barriers to the development of the technology and reduce any environmental risks from its use.
Chris Davies, the British MEP guiding the CCS Directive through the European Parliament, wants to ban all new coal-fired power stations that emit more than 500g of carbon dioxide per kWh of power produced - effectively requiring CCS systems.
Such a measure is unlikely to garner the favour of EU governments, however, and the more likely measure will be a requirement for "carbon capture ready" plants - rules requiring new coal power stations to have the capability of fitting CCS technology at a later date. This would mean having the land and access available to the plant so CCS systems can be fitted when it is available.
Mr Davies is aiming to get an amendment through that would provide extra incentives to companies using CCS technology, for example double emissions allowances under the EU Emissions Trading Scheme.
The MEP for North West England believes that initially CCS will cost around £80 for every tonne of carbon dioxide captured, but that with experience the technology cost will fall to around £24 to £32 per tonne.
Demonstrations
Trials of CCS technology area already underway in places like Algeria, Canada, Germany and Norway. However, this is either on a very small scale or not capturing carbon from the use of coal.
Europe therefore wants to set up a series of commercial-scale demonstration plants to give the technology a test drive and also prove to potential investors that CCS is worth backing.
Proposals have been agreed to set up 12 demonstration projects by 2015, though the exact requirements for projects are yet to be decided. MEPs want to see the demonstration programme supporting projects of at least 180MW in size. It is currently expected that selection criteria for the EU projects will be finalised early in 2009, after which eligible projects will be able to apply to join the programme.
The EU support itself will include a network for projects to share information and best practice experience. A tender exercise to find a company to run the network closed in October, with expectations of an appointment early next year.
UK
In the UK, the government sees CCS as important on energy security grounds as well as for tackling climate change, suggesting coal supplies can be more flexible than supplies of oil or gas.
In particular, large amounts of intermittent renewable energy could need CCS fossil fuel plants as back-up capacity, according to officials.
The government has already started a tender process to set up a single plant demonstration project to store captured carbon in deep underground chambers in offshore locations. The programme, which is hoped will form part of the EU programme, aims to set up an operational plant by 2014 that would capture at least 90% of emissions from a generation plant rated between 300MW and 400MW in size.
The government has decided to limit the programme to post-combustion technology only, explaining that this CCS technology is the least developed and the easiest to "retro-fit" to existing coal power plants.
So far, there is a shortlist of three consortia to build a plant, after BP withdrew from the running:
- E.ON - working with carbon capture technology partner Fluor and carbon storage partner Tullow Oil for a project at the Kingsnorth coal power station, Kent.
- Peel Power Ltd - with partners Mott MacDonald and Danish energy firm Dong Energy, want to build a 1.6GW plant at Hunterston, North Ayrshire.
- Scottish Power Generation Ltd - with Marathon Oil Corporation and CCS technology providers Aker, to turn two units of the Longannet Power Station in Fife to carbon capture systems.
The government is expecting to start negotiations with the shortlisted groups by the end of November 2008, to announce a preferred bidder for the project in May or June 2009.
Elsewhere, RWE npower is also working to develop CCS technology at its Didcot Power Station in South Oxfordshire and its Aberthaw facility in South Wales. However, RWE is focussing on oxyfuel technology.
In the long term, it thought possible by the UK government for CCS to expand to non-fossil fuel technologies, such as biomass, however, this is currently seen as a long way off - despite the potential for negative carbon emissions from such a project.
