Full steam ahead with carbon cuts

Bedford Hospital Trust has a proactive and positive attitude to reducing its carbon footprint and recently achieved the smooth transition to a new, efficient steam generation system. Chris Horsley,MD of Babcock Wanson UK explains




The NHS Carbon Reduction Strategy for England published in 2009 identified the NHS as having a carbon footprint of 18 million tonnes of CO2 per year. To meet the Climate Change Act's targets of 26% reduction by 2020 and 80% reduction by 2050, the NHS aims to reduce its 2007 carbon footprint by 10% by 2015.




Bedford Hospital was one NHS Trust that was quick to react to the figures and to the Carbon Reduction Commitment (CRC) proposals. Its Estates Team concluded the CRC scheme will require the Trust to pay a tax of circa £12/t of carbon produced by the utilities on the main site.




The Trust estimates it produces 9000t of carbon a year, equal to an additional cost of £108,000 per year.



Working with carbon reduction specialists, Bedford Hospital identified a number of efficiency improvements, with the boiler house being the priority.




The boiler house was home to four enormous oil fired boilers which, at 30 to 40 years old, did not provide the level of efficiency expected of current plant. They required thousands of litres of heavy fuel oil, which is expensive and has to be stored on site and maintained at a constant elevated temperature. So in addition to the cost of the fuel itself, there's the financial and environmental costs of continual deliveries to site by road, as well as the costs of keeping the oil on the premises at a set temperature.




By converting the boiler house to natural gas firing, costs could be reduced considerably and on-site fuel storage largely eradicated. In fact, the Trust estimates the conversion to gas will reduce its carbon footprint by 1500 tonnes per year, while also providing improved efficiency - and security - on site for the Trust's main heating source.




The four Firetube Boilers have now been replaced with three Babcock Wanson 2500kg/h ESM Steam Generators fitted with high efficiency exhaust gas economisers.




These new units use coil type steam generator technology giving operating efficiencies of around 94% and low emissions. The Babcock Wanson Steam Generators utilise modern controls to maintain a close ratio between the burner firing rate and water input. This ensures close control of both steam output and steam quality. The burner can be supplied to use different gaseous or liquid feeds, but at Bedford Hospital the primary fuel is gas, with one unit configured for duel fuel operation (gas or oil) as a precautionary measure.




The benefits of using high efficiency steam generators not only include energy consumption and carbon emissions but safety, simplicity of control, compact size and they are quieter, cleaner and cooler in operation.




In addition to the ESM Steam Generators, two Babcock Wanson 1200kg/h VPX vertical coil type Steam Generators have been installed in the new Sterilisation Services Department building.




The boiler house refurbishment was largely completed in summer 2010 and a full review of savings achieved will be carried out shortly. In its Annual Report 2009/10, the Trust states: "A major carbon footprint reduction will be achieved when the scheme currently in progress to change the main boiler fuel from heating oil to gas is completed in summer 2010. This £900k project will reduce our carbon emissions via energy usage by around 15% by removing the need to use heavy fuel oil, as the new boiler plant will use natural gas as its main fuel source."

Bedford Hospital Trust researched the options and possible funding initiatives and put a good team of people together, from inside and outside the Trust, who worked closely together to achieve the transition to an efficient steam generation system. In doing so, it has made a stride towards the NHS' overall 10% carbon reduction set for 2015.