In a novel cogeneration scheme for the UK, London is planning to tap into the wasted heat generated by one of its modern power stations to heat buildings in its Thames Gateway area, resulting in savings of up to 96 000 tonnes of carbon a year.

The UK’s first scheme to retrofit a modern gas turbine power station to harness waste heat and supply district heating to local properties is visionary in its attempt to meet a key climate change challenge: How to heat our homes in the future?

Much work to date on lowering carbon emissions from the country’s energy consumption has centred around new technologies, renewables and building small bespoke on-site combined heat and power (CHP) systems for small-scale developments. But the Department for Communities and Local Government (DCLG) and the London Development Agency (LDA), along with its other stakeholders including Barking Power Limited, are thinking big, right in the heart of London’s key growth corridor – the Thames Gateway. The project has the potential to supply heat and hot water to 150 000 residential and other properties, i.e. commercial, hospital, and schools in the Thames Gateway, with savings of up to 96 000 tonnes of carbon dioxide (CO2) a year.

The scheme will capture the excess heat produced during the generation of electricity by the Barking power station and supply this directly to properties through a hot water pipe network. The power station currently discards almost 50 per cent of the energy it produces through excess heat, which is currently released into the River Thames. It has the capacity to mirror similar district heating schemes already in operation on the continent. The power station will continue to also supply electricity to the national transmission network.

Power partnerships

The project has been developed through a partnership between the DCLG, LDA, Greater London Authority (GLA), London Borough of Barking and Dagenham, as well as other local authorities, Barking Power, London Thames Gateway Development Corporation and Barking Riverside, with the LDA providing the project management.

The Barking power station scheme will greatly benefit the Thames Gateway, which lies at the heart of London’s growth corridor
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The LDA’s head of Decentralized Energy Delivery and Barking Project Director, Peter North observes: “This is one of the most exciting projects today in the field of decentralized energy. It is an innovative and pioneering approach for the UK and for London, to look at how we can take existing power generation facilities and adapt them to help meet the challenge of tackling climate change. If London and other big cities are to really meet this challenge head-on we need to use all of our resources as effectively as possible and explore all opportunities to lower carbon emissions.

“Barking power station is already at the heart of a densely populated area and it is due to become even further populated as a key growth area in the Thames Gateway so this project has huge potential to ensure that those new developments plug into a decentralized heat distribution network.”

Generating power

Constructed in 1995, Barking power station was the first major electricity generating station to be built in London since the closure of Bankside and Battersea power stations in 1981 and 1983, respectively. It is one of the largest independently-owned generating plants in the UK and is capable of generating 1000 MW of electricity. This represents about two per cent of the peak electricity demand in England and Wales as a whole. The station has recently been given planning consent to construct a new 470 MW extension to increase its capacity even further, which will also plug into the heat distribution network.

Using combined-cycle gas turbine (CCGT) technology, with gas as its primary fuel, the station has a lower environmental impact than other older stations. CCGT is one of the cleanest and most efficient forms of power generation in commercial use. Barking is able to generate electricity at more than 50 per cent thermal efficiency and produces low levels of emissions. The district heating scheme will increase its environmental credentials even further.

The district heating pipes illustrate the size of the proposed transmission main
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The Barking district heating project first came to life in 2004 when the London Borough of Barking and Dagenham began investigating whether there was potential to capture the heat from the power station to supply its local housing stock and Barking Riverside. In 2005, a partnership was formed between London Borough of Barking and Dagenham, LDA, GLA and the London Energy Partnership to conduct a review of the power station’s performance and initial feasibility study. The review established that 400 MW of low-grade heat was produced as a by-product in the electricity generation process and was discharged into the River Thames. The study by consultants Parsons Brinkerhoff indicated that there was potential to put this surplus heat to good use. The report found that not only could all new developments in Barking and Dagenham be heated, but that it could heat a large number of the new developments in the London Thames Gateway. Another of the report’s findings showed that the cost of offering decentralized heating to new developments, was comparable in price to traditional heating methods, but with the added benefit of a 22 per cent carbon saving.

A detailed feasibility study was completed earlier this year by Danish consultant Ramboll, which was involved in setting up a similar scheme in Copenhagen. It identified 37 000 new homes that could be supplied in the short- to medium-term, and 150 000 in the long-term in the Thames Gateway area as new developments are built. The first homes to benefit would be in new developments in Barking Riverside, the Royal Docks, Havering Riverside and Barking town centre.

The Ramboll report has identified the design arrangement necessary for the hot water network. Upgrading the existing plant and building a heat transmission network comprising flow and return pipeline running east and west from the power station. This will supply new homes in its initial stages, displacing the need to use gas for heating and therefore saving around 35 000 tonnes of CO2 output each year. It is estimated that the first customers could be supplied in 2011. Consultant Arup is also conducting a review of the strategic planning issues that the project presents to ensure national legislation, regulations and any barriers are taken into account.

Future-proof scheme

One of the long-term benefits of the project is its scalability. Once the initial pipework is established, further new housing developments can be plugged into the main distribution network at ‘nodes’, with local distribution networks taking the hot water supply directly to customers at competitive cost. Over time, a fully-fledged heat network would evolve, linking other heat suppliers with new and existing heat users such as hospitals and schools and housing.

North says the potential is huge: “This scheme is future-proof. We can just keep plugging in new developments, existing properties where feasible and new sources of affordable low carbon heat as they become available. Network capacity is not a problem as the system can easily be extended by using booster pumps and additional heat sources at strategic points.”

The construction phase is expected to take around three years, beginning in 2010, with the project costing around £100 million ($177 million). It is expected that the first home connection to the network will occur in 2011. The construction phase will include modifying the power station for the heat take-off arrangements, the construction of a district heating pumping station and manufacturing and installing hydraulic interface units to connect the district heating network to the end users. A steering group has now been formed to direct project implementation, comprising DCLG, LDA, London Thames Gateway Urban Development Corporation, Barking Power, GLA, London Borough of Barking and Dagenham, London Borough of Havering, London Borough of Newham and Barking Riverside. The DCLG, LDA and Barking power are all contributing funding to the initial development.

Decentralizing London power

The initiative to convert the power station to operate as a CHP plant, however, is more than just an engineering challenge; it is seen as the test-bed for a new energy policy. Decentralized energy is rapidly gathering pace over centralized production because of the latter’s inefficient use of the primary fuel and the costs and losses of distributing electricity over long distances. Locally generated power and recovered heat to supply substantial heat loads is highly efficient and works well in densely populated urban areas such as the Thames Gateway.

The Mayor of London is committed to reducing London’s carbon emissions by 60 per cent below 1990 levels by 2025. One of the key strategies to achieve this target is by significantly increasing the use of local lower-carbon decentralized energy systems in the capital. In partnership with the London boroughs, the Mayor wants to maximize opportunities for providing new networks that are supplied by decentralized energy in borough local development frameworks. The Barking power station district heating project would be a significant contribution to the implementation of London’s decentralized energy strategy, providing new and existing developments in east London with the opportunity to connect to a lower carbon heat network and encouraging boroughs to strategically plan for district energy infrastructure.

The project will also help developers to meet some of their requirements under the Mayor’s London Plan to connect to decentralized energy networks to lower the carbon emissions of new developments.

The first sod of turf may not yet have been turned to lay the pipes, but already the project is causing a stir as developers and policymakers alike tap into the scheme’s potential.

North is pleased that the hard work getting the project off the ground is beginning to pay-off: “All the initial groundwork and feasibility studies are really paying dividends now because people can now really see what the possibilities are and the real difference the project can make. The figures speak for themselves on the potential CO2 savings, and the technology is already proven on the continent. It’s a win-win situation for everyone from developers to policy makers to residents themselves.”

For more information on the London Thames Gateway Heat Network project click on the following link: www.LTGHeat.Net