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Birmingham uses CHP and trigeneration in district energy scheme

Since its conception in 2003, the Birmingham District Energy Scheme has continued to expand and play an increasingly important role in Birmingham City Council’s climate change strategy, which aims to reduce carbon dioxide emissions by 60% by 2025. Simon Woodward writes.

The Birmingham District Energy Scheme is owned and operated by Cofely District Energy, working in partnership with Birmingham City Council (BCC), Aston University and Birmingham Children’s Hospital, under the name of Birmingham District Energy Company Ltd (BDEC).

The scheme was conceived in response to a long-held vision by BCC and Aston University to develop large-scale energy supplies in the centre of Birmingham. Following a feasibility investigation in 2003, which included visiting other schemes such as the Southampton District Energy Scheme, two schemes were identified – Broad Street and Eastside. In an innovative procurement scheme, tenders for delivery were issued jointly by BCC and Aston University through OJEU (the Official Journal of the European Union), and Cofely District Energy was selected as the preferred partner. The first 25-year energy supply agreement between the partner organizations was signed in 2006 and the Eastside scheme energy services agreement, also for 25 years, was signed in 2008–2009.

This is a trigeneration scheme producing heat, electricity and chilled water – making extensive use of large-scale combined heat and power (CHP) technologies and using conventional boilers for ‘top up’, standby and increased resilience. The electricity from all the CHP units is used directly via private wire connections into each of the buildings/sites. Chilled water is generated by absorption chillers, powered by heat from the CHP and boiler plant. Overall, the Birmingham scheme is saving over 12,000 tonnes of carbon dioxide per annum compared to traditional systems.

Financial savings for the schemes are developed on a whole life costing basis and maintained throughout the contract by indexing charges to national fuel prices, the retail price index etc. As the scheme expands, any profits will be shared with the core customers, with 100% transfer of risk to Cofely.

Aerial view of Birmingham

From the start, BDEC’s intention was to extend the three core schemes and, due to the system’s significant delivery of financial and carbon savings to its consumers, it has grown rapidly since its inception and continues to evolve with the addition of new customers and the introduction of low carbon technologies. The scheme is also being extended into several regeneration areas across the city and, ultimately, all of these ‘sub-schemes’ will be linked together to improve resilience and maximize energy saving opportunities.

BROAD STREET SCHEME

Launched in 2007, the Broad Street trigeneration scheme was the first phase and encompassed a range of buildings in the central business district served by an energy centre at the International Convention Centre (ICC).

Plant at the ICC energy centre comprises a 1.6 MWe CHP unit, 7.3 MW of additional heating using gas-fired boiler plant, and 4.9 MW of chiller capacity for the generation of chilled water. In 2008, this was supplemented by a 600 kWe CHP engine installed at the National Indoor Arena.

Hot and chilled water from these energy centres is distributed through underground pipework networks that connect a range of buildings in and around Broad Street. As the scheme expands, further satellite energy centres will be created in strategic developments connecting the scheme, linking into the networks serving the core buildings along Broad Street.

Electrical power generated by the CHP plant in the energy centres is used to offset some of the power consumed from the grid by the buildings in the scheme.

The Broad Street Scheme saves over 3800 tonnes of carbon dioxide per annum, a figure which will increase as new consumers are added to the network. These will include the Library of Birmingham, a new central library for Birmingham currently being developed on land adjoining the Birmingham Repertory Theatre (the REP).

In 2010, BCC also added Cambridge & Crescent Towers to the Broad Street scheme, by converting these electrically-heated affordable housing blocks to use the district heating, saving around 340 tonnes of carbon dioxide per annum as well as significant cost savings compared to the electric heating system.

Current users of the Broad Street Scheme include:

• the Town Hall

• the Council House

• the Hyatt Regency Hotel

• the REP Theatre

• the International Convention Centre

• the National Indoor Arena

• Paradise Circus

• Cambridge & Crescent Towers.

THE EASTSIDE SCHEME

The Eastside Scheme is split into two phases – the Aston University Scheme and the Birmingham Children’s Hospital Scheme. The location of the Eastside schemes means both networks can expand into regeneration areas of Birmingham. In addition, the Eastside redevelopment of Birmingham New Street Station has the potential to become a hub for interconnecting the Broad Street and Eastside schemes.

The Aston University Scheme began operations in 2009, with 3 MWe of CHP capacity installed at BDEC’s Jennens Road Energy Centre. However, before the scheme was completed, further contracts with third party consumers had already been signed. So although the initial projection was for an annual reduction in carbon dioxide emissions of 5300 tonnes, this figure is set to increase significantly as new users are connected.

One such user is BCC’s new Woodcock Street 21,000 m2 administration block in Aston Science Park. Connection to the Aston University scheme will enable BCC to achieve a UK BRE Environmental Assessment Method (BREEAM) ‘Excellent’ rating, whilst saving over 890 tonnes of carbon dioxide per annum. The building will take energy from June this year, ahead of occupation later in the year.

In 2010 an additional energy centre with 1.6 MWe of CHP capacity was constructed to serve the Birmingham Children’s Hospital and Birmingham City Council’s Lancaster Circus Offices. This scheme delivers a further carbon dioxide reduction of 3500 tonnes per annum.

In addition, in August 2010, Cosmopolitan Housing Group confirmed that it will take heat from the scheme for its new Birmingham student accommodation. Cosmopolitan’s commitment to take energy ahead of the scheme’s operation reinforces developer confidence in BDEC and its ability to deliver energy on-time and to consumer’s requirements and specification.

Cosmopolitan’s new Bagot Street development comprises 656-room accommodation for students, which will take heat from the extended Eastside scheme from July, ahead of the 2011–2012 academic year. The connection is projected to save around 660 tonnes of carbon dioxide per annum, compared to the conventional heating system that had been proposed for the building.

The Masshouse develop-ment site in Eastside is also enthusiastic about the scheme and has signed an agreement to connect a second residential block (Block M) comprising 167 apartments in Birmingham’s Eastside. Masshouse will be upgrading all of the apartments from an all-electric heating system to a wet central system connected to the low carbon district energy scheme. The connection has allowed Masshouse to achieve a ‘Code for Sustainable Homes’ Level 4 rating, for a development whose original design and build had been to earlier design codes.

The agreed heat tariff with Masshouse provides a significant price advantage over the previously installed electric heating system, and enables around 400 tonnes of carbon dioxide per annum to be saved as well. The lead time to supplying heat was critical to Masshouse, with completions and handovers of Block M apartments to leaseholders commencing in March 2011. BDEC agreed to start supplying heat from the end of October 2010, to support Masshouse in meeting its obligations to achieve practical completion of the development.

Previously, during 2009, Masshouse had reached a deal with BDEC under which a new HMCS magistrates court connected to the Birmingham District Energy Scheme, achieving a BREEAM ‘Excellent’ rating, and Masshouse’s Site 7 was pre-serviced with low carbon infrastructure – a first for any UK private developer.

Buildings served by the Eastside scheme include:

• Aston University Main Campus,

• Lancaster Circus (Birmingham City Council),

• Birmingham Children’s Hospital,

• HMCS – Magistrates Court,

• Masshouse,

• Woodcock Street Administration (Birmingham City Council),

• Cosmopolitan Birmingham Student Homes.

RESILIENCE AND NEW ENERGY SOURCES

Birmingham’s district energy schemes are designed to be at least as resilient as conventional supplies. For example, if a CHP engine is off-line for planned or reactive maintenance, sufficient top-up and back-up plant is in place to meet the demands of the energy network. BDEC achieves this by linking and installing additional boiler/chilling plant, and ensuring there is a grid connection.

The City’s district energy networks have also been designed to integrate new, emerging technologies such as fuel cells and renewable heat sources, as overall energy demand and improved efficiencies makes these technologies financially viable. BDEC expects to add substantial renewable energy generation to the schemes as new consumer connections are made. This will not only reduce emissions but will also help to future-proof the scheme against fossil fuel shortages.

The Broad Street CHP scheme

SUSTAINABLE GROWTH

Considerable financial, environmental and planning benefits make joining the Birmingham District Energy Network an extremely attractive proposition for building owners, developers and residents.

The reinvigoration of Birmingham City Centre, coupled with the considerable gains associated with connections to the scheme, have resulted in the rapid expansion of BDEC’s district energy networks to third party consumers. These third party connections are made possible through a mixture of public and private connection agreements and grants. Contracts are typically for at least 20 years and, crucially, the value of the initial cost saving is maintained, in real terms, over the life of the contract through a transparent system of annual indexation.

Financial savings are typically achieved in two ways. Firstly, capital costs are about 20% lower than those of installing a conventional heating system in the building. Furthermore, there are significant savings on plant room space, so valuable city centre space can be used for other purposes. Altering heating and cooling systems when switching to the district energy scheme is also unnecessary, as temperatures and pressures are unchanged.

Secondly, the inherent efficiency of the district energy schemes means that most consumers can expect to save 5–10% on their overall energy bills, compared to traditional methods. Many users of the scheme are also required to participate in the UK government’s Carbon Reduction Commitment Energy Efficiency Scheme, so their energy savings through using district energy enable them to reduce their expenditure on carbon allowances.

Future plans include further expansion and interconnection of the hot water networks to supply heating across the entire city centre. This will enable heat to be added at various locations, provided by alternative sources that can be used across the network. These alternative heat sources could include food waste, general waste and biomass fuels. There is also scope for generating more electrical power at specific points to supply directly to major consumers. The overall target is to increase carbon savings from 12,000 tonnes per annum to 20,000 tonnes by 2015.

Simon Woodward is the Chief Executive of Cofely District Energy, Crawley, Surrey, UK.

Email: simon.woodward@cofely-gdfsuez.com

This article is available on-line. Please visit www.cospp.com


Key facts and figures

• capital cost of around £7 million investment by Cofely District Energy

• over 41,000 MWh of heat per annum

• 35,000 MWh of electricity from the CHP plan

• more than 4900 MWh of chilled water

• 4 km of insulated distribution pipe

• electricity supplies synchronized with the

• National Grid

• just 0.5°C temperature loss per km of pipe

• hot water flow/return temperatures of approximately 95°C/60°C

• savings to local business of over £0.5 million per year

• carbon dioxide emissions reduced by 12,000 tonnes per annum.

Business benefits to third party consumers

• capital cost savings – connection charge up to 20% less than conventional plant

• space savings – direct connections mean no plant space required

• planning gains – no roof-mounted cooling plant and environmental benefits

• operating cost benefits – up to 10% cost savings compared to alternative methods of heating/cooling

• guaranteed savings – prices linked to market levels to ensure savings are maintained

• carbon savings – delivers on LA21, Kyoto and CSR targets

• risk transfer – with off-site energy supplies served by several energy centres.

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