Subsea gas pipeline planned for Thames power stations
Carbon capture and storage (CCS) technology will see emissions from Kingsnorth Power Station transported via a subsea pipeline to a disused Nort Sea gas field. Photo courtesy of E.ON
Survey work is under way in the Thames Estuary in preparation for a 270km long subsea pipeline proposed by E.ON that will transport CO2 gasses from seven power plants and a refinery in the Thames and Medway area to a carbon capture and storage facility at the disused Hewett gas field in the North Sea off Norfolk.
Wind energy is increasingly viewed as an important way forward but satisfying the UK’s electricity needs will always involve a mix of renewable, fossil fuel and nuclear sources maintaining a balance between security of supply and the cost of the electricity itself. The Stern Review of 2006 highlighted the importance of carbon capture and storage (CCS) technology to help reduce greenhouse gas emissions from the power industry until low carbon processes become a reality.
Depleted oil and gas fields in the North Sea have been identified as providing potential locations for CCS, the process whereby CO2 gasses are injected deep underground where they can be stored for around a thousand years. The location of such fields in relation to the UK as a whole favours CO2 emitters on the eastern side of the UK and three groups of power producers have been identified; the Thames, Humber and Scottish clusters.
With the Greater London area being the largest consumer of electricity in the UK, the Thames Cluster is seen as providing an early opportunity to gain maximum effect from the process. The region is expected to have a requirement for around 13,500 MW of electricity in 2015. Potentially 28m tons of CO2 could be recovered annually from eight plants in the Thames and Medway area with over half of this amount originating from the two planned new technology coal fired power plants at Kingsnorth and Tilbury. It is proposed that they will be the initial supply sources for the CCS pipeline. The collection and transportation network has been compared to the current National Grid arrangements for electricity and gas and would in time allow the other power stations in the Thames Cluster at Barking, Medway, Damhead Creek, Coryton, Rye House, Grain CHP, Enfield and Littlebrook together with the refinery at Coryton to be connected to the network.
An overland pipeline was considered but a subsea route is seen as the best option given the offshore industries experience of subsea oil and gas pipelines. The gas will be compressed and liquefied for the journey out of the Thames Estuary and up the East Anglian coast, terminating at the Hewett gas field. This route would also allow CO2 from Great Yarmouth Power Station to be added to the link.
There are similar plans for the Humber cluster to be linked to the Viking Field with the Leman and Indefatigable fields also considered good storage sites for both the Thames and Humber clusters. However there are currently no plans to construct CCS plants at the three large power stations on the Scottish east coast known as the Scottish cluster.
For the waters of the outer Thames Estuary the proposed pipeline would bring additional work for the related industries in an area that has seen significant current and future subsea power cable installations recently from the Kentish Flats, Thanet Offshore and London Array wind farms and the BritNed electricity interconnector.
By Peter Barker
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