RYE HOUSE POWER STATION SITE INFORMATION OVERVIEW Rye House Power Station is company acquired the 715 located near the market enough to meet the daily one of three combined cycle megawatt (MW) plant in town of Hoddesdon, power needs of around gas turbine (CCGT) stations early 2001 to supply its Hertfordshire, about 18 400,000 homes – or almost operated by ScottishPower customer base in England miles north of London. the entire population of Issue 02/2009 Energy Wholesale. The and Wales. The station is Output from the station is Hertfordshire. INTRODUCTION TO RYE HOUSE POWER STATION The Rye House site, bounded by the River Lea and the main London to REDUCING OUR ENVIRONMENTAL IMPACT Cambridge railway line, has strong links with the electricity generation industry. A key advantage of modern process. The use of cooling A coal-fired power station occupied CCGTs like Rye House is their towers for a station the size of the site from 1953 to 1984. efficiency at converting fuel Rye House would have required It was designed by architect Sir Giles into electrical energy – typically a million gallons of river water to Gilbert Scott who was better known for more than 50%. be extracted each day. designing Battersea Power Station and That means less fuel The ACC was increased in Liverpool Cathedral. consumption and lower levels of size by 10% in 2006 to improve Meanwhile, an open cycle gas-oil emissions per unit of electricity its efficiency, especially in warm power station, that worked using generated compared with weather. modified aeroplane engines, was built conventional thermal stations. Low-noise fans were also on the site in 1966 and operated for 18 The station operates subject installed to reduce the impact on years. The combined cycle gas turbine to conditions contained in a local communities. (CCGT) power station was opened in permit issued and enforced by The station has successfully 1993. the regulators, the Environment I The air cooled condenser reduced its water usage E fforts were made to reduce the Agency (EA). following the installation of water visual impact of Rye House during its A Continuous Emission Technology (BAT) requirements collection systems that trap construction by careful use of colour, Monitoring (CEM) system has for the reduction of NOX as part run-off rainwater from the station architectural treatment and extensive been installed on each of Rye of the Integrated Pollution roof and compound. landscaping, including the creation of a House’s stacks to demonstrate Prevention and Control regime. This water is filtered and 3.6 hectare conservation area. to the EA that emissions limits The new system replaces a treated for use as process water, Rye House has an excellent track have not been exceeded. previous Low-NOX burner reducing by up to 75% the record of environmental compliance. It Natural gas does not give rise system and helps to optimise amount of townswater that’s also enjoys a positive relationship with to significant emissions of dust, combustion performance, required. its neighbours and actively participates ash or sulphur dioxide (SO2) – resulting in an improvement on The initiative was highlighted in community life. Staff raise funds for an which has been linked with “acid previous NOX emission levels of as good practice in the adopted charity – the Isabel Hospice in rain” damage to ecosystems and between 40-50%. Environment Agency’s annual Welling Garden City – and support local respiratory irritation in humans. Meanwhile, combustion report for 2007. safety education projects for children. Meanwhile Rye House Power chambers, incorporating hot Staff seek to minimise waste Station employs sophisticated ceramic liners, converts all the from the site and actively recycle abatement technology to control carbon in the fuel into CO2 rather paper, card, oil, scrap metal, CONTACT US emissions to air of oxides of than carbon monoxide (CO), wooden pallets and solvents. nitrogen (NOX). which is highly poisonous to Rye House operates an Rye House Power Station New Dry Low-NOX burner human health if inhaled. Environmental Management Hoddesdon, technology is being fitted to Rye House uses an air-cooled System that is certified to the Hertsfordshire EN11 ORF each of the station’s three gas condenser (ACC) to minimise international standard, ISO telephone: 01992 448604 turbines. This will ensure Rye the quantity of cooling water 14001 and is implementing a web: www.spenergywholesale.com I Rye House Power Station with its distinctive triple stack House meets Best Available required for the generating site biodiversity action plan. RYE HOUSE POWER STATION SITE INFORMATION HOW IT WORKS site water supply Emissions to air – NOX and CO2 – all potable water Rye House uses three gas >> INPUTS >> OUTPUTS turbines and a steam turbine that together provide the most potential efficient form of thermal Energy environmental electricity generation. noise Natural gas is delivered to the site via a 20 kilometre pipeline that links in to Tr a n s c o ’s GT GENERATOR GT TRANSFORMER national transmission system. AIR IN The fuel is burned in three gas turbines (GTs), which are similar to the large jet I Rye House’s control room GT low pressure steam Electricity generated COMPRESSOR engines found on aeroplanes, to mixed with steam from the low heat compressed air. pressure side of the heat GAS IN high pressure steam STEAM TURBINE The hot gas expands TRANSFORMER recovery boilers before entering GT POWER Total waste through the turbine blades HP exhaust the low pressure turbine. COMPRESSOR steam produced at 3,000 RPM, forcing a shaft to rotate and drive a generator. In conventional-fired power Exhaust steam flows to the station’s air-cooled condenser (ACC), one of the GT exhaust gases STEAM TURBINE GENERATOR stations, the hot exhaust gases largest in Europe, that cools it domestic and recycled are lost to the atmosphere, dirty water waste back into water to be recycled in STEAM resulting in wasted heat energy. the Heat Recovery Boilers. foul & trade effluent EFFLUENT recovered LOW PRESSURE TURBINE blowdown STEAM TURBINE GENERATOR At Rye House, these The ACC at Rye House pumped to RETENTION water gases, at a temperature of covers an area of more than sewer PIT HIGH PRESSURE 540OC, are reused to heat STEAM TURBINE exhaust 7,000m3 – the size of one and a steam water-filled tubes in three Heat regeneration half football pitches. It works by waste water condensate Recovery Boilers. releasing heat through 600 return to boiler Each boiler contains over 120 km of tubing that is filled with radiator units mounted 24 metres above the ground. Townswater water WATER TREATMENT PLANT AIR COOLED CONDENSER RAINWATER RETENTION PIT rain water pumped to River Lea purified townswater. The water These are made up of 60,000 treatment make up to ACC in the tubing is heated by the lengths of oval finned tube chemicals hot exhaust gases and steam is which, if extended end to end recovered rainwater from rainwater harvesting plant produced, at two different would stretch over 160 km. pressures, in order to maximise Cooling is enhanced by the heat recovery. use of 100 fans with a blade ENVIRONMENTAL PERFORMANCE HIGHLIGHTS 2008 Waste gases from this part of the process are diameter of 6.1 metres that rotate at 72 rpm. Rye House Power Station operated burners have reduced NOX resources. Rainwater harvesting released to the atmosphere through the station’s three chimneys. Townswater is used for domestic purposes and, following treatment, as boiler flexibly in response to market conditions in 2008 and generated emissions on two of the units by approximately 50%. supplied 40% of the station’s process water in 2008 – and The steam created passes through the steam turbine, which drives a 250 MW feedwater. Quantities of blow down water and rainwater are also recovered, then filtered, for 4,381 GWh of electricity – an increase of 45% from the total in 2007 (3,004 GWh). The third and final burner on GT11 is being fitted in 2009. The station continued to maintain further water savings are anticipated as measures identified in a water audit during 2008 are generator, expanding as it does use as process water, replacing This significant increased high standards of environmental put into effect. so, with its heat energy driving the use of townswater. production followed two successive compliance – there were no Meanwhile, further opportunities the turbine rotor at 3,000 rpm. The steam leaves the high pressure turbine at 194OC and a Only small quantities of water are released to the River Lea, a source of drinking years when major outages took place to install new generation gas turbine (GT) burners at Rye House. breaches or incidents in 2008 and no community complaints. Meanwhile, station staff continue to improve office waste recycling are being rolled out. Rye House already recycles paper, oil and pressure of just over six bar. It is water for London. The new, high-efficiency GT to tackle waste and the use of scrap metal.