A greener York with Dalkia at Derwenthorpe

Large-scale low-carbon housing for Derwenthorpe

Derwenthorpe, on the outskirts of York, is the latest coup in large-scale low-carbon housing design in northern England, developed by the Joseph Rowntree Housing Trust in cooperation with David Wilson Homes. It will provide a total of 540 homes consisting of 2, 3, 4 and 5 bedroom residences for sale, rent and shared ownership. Recently, the first phase of the Housing Design award-winning (2010, 2013) community development project has been completed, with 64 houses built at 27 dwellings per hectare. Project completion is expected in 2019.

All Derwenthorpe homes are supplied with heat and hot water from a communal heating system that heavily relies on biomass for heat generation. Owen Daggett, Sustainability Manager at the Joseph Rowntree Housing Trust, elucidates:

"The plant is located in the middle of the development and will be delivered with wood chip twice a week during the winter months once all the houses have been built. In fact, the'Super Sustainable Centre', as the building has been named, unites Derwenthorpe's energy centre and community centre under one roof to signify what is at the heart of this development: close-knit community and environmental sustainability. The biomass heating plant is an integral part of this master plan. In line with the project's green ambitions, Dalkia supplies heat with a carbon dioxide emission equivalent of no more than 0.07kg/kWh."

Heat is currently generated by one 320kW biomass boiler and by two 640kW natural gas boilers. The biomass boiler is fuelled by wood chip that Dalkia sources internally whereas the gas boilers serve as an emergency backup and for heat top-ups when demand throughout the district exceeds the biomass heat capacity.

"Over the next six years as the houses are built, Dalkia will continue to provide engineering design assistance and add a second biomass boiler to the energy centre, to create a total biomass heat capacity of 990kW. At full build out, the biomass boilers are expected to use 18 tonnes of wood chip weekly", says Jason Clarke, Project Development Manager at Dalkia.

Besides installation and pipework, Dalkia provides an extensive service package to maintain the facility, ranging from biomass procurement to operation and life cycle management. "On top of its technical services, Dalkia has taken on responsibility for billing and invoicing the associated households, which will help us to manage resident relationships more efficiently", Owen Daggett adds.