Power Behind the Games

10 December 2010

First to the starting line at the Olympic Park in Stratford is the Energy Centre, built and operated by COFELY. It opened recently and is already powering the construction of the Olympic facilities, as Jane Fenwick reports

WHEN THE OLYMPIC PARK hosts the Olympic Games in 2012, it will need a lot more than just muscle power to make the event work. Last month saw the official opening of the first part of the complex energy infrastructure that will support the stadia facilities, media, accommodation and everything that needs power to operate.
The Kings Yard Energy Centre was officially opened by Mayor of London Boris Johnson, ODA Chief Executive David Higgins and Gérard Mestrallet, Chairman & CEO of GDF SUEZ who will own and operate the new facility in a 40 year deal.
Not only will the Energy Centre power the Games venues but it also designed to deliver a legacy of sustainable energy across the site beginning now. The largest energy centre scheme to be built so far in the UK, it will contribute towards the ODA’s overall target to reduce carbon emissions by 50 percent.
It has been designed, financed and built by COFELY, the energy services subsidiary of GDF SUEZ and represents a significant investment by the company, who also laid approximately 16km of Community Energy Networks. COFELY will also operate the Centre for the next 40 years.
Sited at the western perimeter of the Olympic Park, Kings Yard is first of two energy centres to be built on the site - the other being the Stratford City Energy Centre at the east of the site for providing power to the Stratford City retail and entertainment venues and the eastern side of the Olympic Park. Kings Yard uses both biomass and a natural gas powered Combined Cooling Heat & Power (CCHP) which is 30 percent more efficient than traditional power generation methods. The CCHP system design is modular, with space allowed for future increases in capacity – to a maximum load of 120 MW heating, 25 MW cooling and 17 MW of low carbon electricity – enough to power 100,000 homes. Currently the generation capacity is for 46.5 MW of heating and 16 MW of cooling.
Tony Merrell, the M&E construction manager explained that the CCHP supplies electricity, while waste heat is reclaimed for heating water. In addition absorbtion chillers convert the waste heat from the flue to chilled water through lithium bromide system. “Lithium bromide is a salt which when heated turns into gas, and it is that process that provides the chilled water system. We envisage that as the site develops demand for power, heat and cooling will build up. The legacy plan for after the Olympics is for two more boilers to be placed adjacent to the two existing ones installed at Kings Yard.”
Using absorbtion chillers means that the district energy network is able to increase the operational hours of the plant with an increased utilisation of heat, particularly in summer
periods. Peak cooling demands are met with supplemental chilled water from traditional chillers.
The boilers generate hot water at operating temperatures of 95ºC for distribution to the various users of the Community Energy Network and are designed to achieve high fuel
efficiencies at all operating loads, consistent with maintaining stack exit temperature at 100ºC. The boiler circuit normal working pressure is in the region of 6.0 bar.
The water quality within the system is maintained in accordance with British Standard BS6880 with the use of softening, filtration, degassing and auto dosing equipment. A forced draft fan mounted on the burner front provides optimum air condition for combustion plus a suitable margin for safe combustion and control requirements across the entire firing range. The boilers are connected to the flue system that leads to a common flue tower approximately 45m high.
The Energy Centre’s boiler room ventilation consists of fans at roof level that supply air into the space at low level via mesh grilles on the ductwork within the building. These have been
provided at regular points for good air distribution to the boilers. The Energy Centre is maintained at a positive pressure as required by BS 6644:2005 and IGE/UP/10.
Excess air is exhausted to the atmosphere naturally via louvres at a high level in the external façade and this meets the noise requirements imposed upon the site. Designed by John McAslan & Partners, the building was granted planning permission in July 2008 with construction beginning in September that year. The innovative construction used over 500 tonnes of steel and 3,500sq m of concrete planks to form the floors and roof. The exterior incorporates demountable pre-weathered steel panels over a timber frame, structural insulating panels and a re-sealable membrane. This will allow additional plant capacity and future low carbon technologies to be implemented in a cost effective manner.
Adjacent to the Energy Centre building are two 750 cu m thermal storage tanks, and a 750 cu m treated water store. The thermal storage tanks allow water to be heated in the most efficient manner and stored ready for use.
Also adjacent is a retained Edwardian former sweet factory which will house a bio mass plant powered by wood chip, and which has a further two storage tanks. Part of this building will be converted as a visitors centre.
The community, or district energy system, will produce hot water and chilled water from the two energy centres – Kings Yard and Stratford. The water is then either stored, or piped directly underground to individual venues and buildings for domestic hot water, heating and air conditioning. Individual buildings do not need their own boilers, chillers or air conditioning units.
The underground insulated distribution network across the Olympic Park, Olympic Village and Stratford City has involved the laying of over 16 km of heating and 2 km of cooling pre-insulated distribution pipework. Pipework ranges from 50 mm to 700 mm diameter and there is a sophisticated leak detection system installed.
The network is designed to operate at low temperatures thereby minimising energy losses. It carries hot water at 95°C, returning at 55°C, at a rate of up to 400 litres per second (l/s). This may be increased to more than 1000l/s in legacy mode to meet the needs of the Olympic Park as it is developed after the Olympic Games.
The network is connected to 48 heating and 23 cooling sub-stations within the park venues, buildings, Athletes’ Village and Stratford City development. The sub-stations are prefabricated and brought to site when required.
The network has a high level of resilience ensuring security of supply, The pumps for each system provide the water circulation via flow and return headers. Each pump is speed
controlled to maintain the required demand in the district heating/cooling return temperature fluctuations. While only one pump is required to meet demands, a standard pump set consists of two or three duty pumps to ensure that the Energy Centres provide a resilient service to its customers.
The Stratford City Energy Centre will house an efficient low carbon heating and cooling system using a gas-fired CCHP and biomass fired boliers using sustainable biomass fuels.
Planning permission was granted in August 2008, and it will be completed in early 2011.
COFELY District Energy has considerable experience in this sector. It operates, maintains and manages 12 major schemes throughout the UK, many of which it owns. These schemes
include Birmingham District Energy Company, Southampton Geothermal Heating Company Media City, Manchester; Whitehall; Bloomsbury Heat & Power Company as well as Olympic Park and Stratford City.