National Heat Map: Water Source Heat Map Layer

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National Heat Map:Water source heat map layerMarch 2015

Crown copyright 2015URN 15D/091- National Heat Map: Water source heat map layer.You may re-use this information (not including logos) free of charge in any format or medium,under the terms of the Open Government Licence, unless otherwise stated.To view this licence, visit cence/or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,or email: [email protected] enquiries regarding this publication should be sent to us at [email protected]

Water source heat map layerContentsExecutive summary . 5Introduction . 7Background . 7High level water source heat map . 7Water source heat pumps . 7Aims and objectives. 8Terminology. 8Coverage . 11Constraint mapping . 12Overview . 12Environmental designations . 12Rivers . 15Water resource availability . 17Canals . 18Coastal and transitional waterbodies . 19Calculating water source heat capacity . 20Water temperature . 20Changes to temperature . 21Heat pumps . 22Water availability . 22Aggregating urban areas . 23Summary of input datasets and associated licencing . 24Summary of heat capacity findings . 25Rivers . 25Urban areas . 28Sensitivity analysis . 34Canals . 36Coastal and estuary. 37Conclusions . 39Limitations . 393

Constraint MappingFurther recommendations . 40Data structure . 42Summary of input datasets and associated licencing . 42Overview . 43Methodology flowchart. 44Key assumptions . 45Water temperature . 46Intake temperature for rivers, lakes and reservoirs . 47Intake temperature for estuaries and the sea . 47Limits to changes in water temperature . 49Water availability . 49River flow . 50Canals. 51Estuaries & coast . 52Heat pumps . 52Rate of heat extraction . 534

Executive summaryA detailed water source heat map has been developed for localauthorities, community groups and private developers to highlight theopportunities for deploying innovative heat pump technology,particularly at larger scales (e.g. for heat networks).Last year, DECC published a ‘high level’ water source heat map1, which raised awareness ofwater source heat pumps and provided an early estimation of the potential to generate heatfrom 39 English rivers. The purpose of this more detailed study was to produce a more robustestimate of the potential for water source heat pumps across England. The output, a WaterSource Heat Map (WSHM) layer, has been integrated into the National Heat Map (NHM)2. TheNHM provides heat demand and sources (e.g. local CHP generation stations) in an accessibleway to support DECC’s vision for low carbon heat3.This study has drawn together a number of existing data sets and methods to produce a newmodel providing a strategic assessment of the suitability of England’s waterbodies for heatextraction. It has identified areas where environmental factors may potentially constrain watersource heat pump installation, and the locations with the highest potential for open loop watersource heat pumps.At a strategic level this study has come to the following conclusions about the heat capacity ofEngland’s waterbodies: The total heat capacity of rivers is strongly proportional to flow. Urban areas on largerrivers are therefore prime candidates for water source heat pumps, and linking up toheat networks in the future. Urban areas close to rivers with over 100 MW total capacityare identified on the rivers Ouse (Yorkshire), Trent, Thames, Severn, Aire and Wye.Particularly promising urban areas include Nottingham, Hereford, Pontefract andLondon. A comparison with the results from the previous ‘high level’ study shows somesignificant differences. The approach used in this study has given equal weight to smalland large urban areas. Consequently small urban areas on large rivers are moreprevalent. Additionally, the previous study did not include any locations on the RiverSevern. The total heat capacity from rivers is estimated at approximately nalheatmap/Department of Energy & Climate Change, “The Future of Heating: Meeting the challenge,” March 2013. [Online].Available: ds/attachment data/file/190149/16 04-DECCThe Future of Heating Accessible-10.pdf35

Constraint Mapping The study suggests that smaller urban areas with lower heat demands (less thanaround 500 GWh per year) on larger rivers can have their entire heat demand satisfiedby the river alone. Examples include Egham, Tewkesbury, Bewdley, Stourport-onSevern, Chertsey, Ross-on-Wye, Goole, Gainsborough, Wallingford and Selby. The flow and lower temperatures in canals restrict their heat capacity significantly incomparison to large rivers. However, in locations where the canal network is asignificant waterbody compared with local rivers (e.g. West Midlands) canals may bethe best source of heat. The total heat capacity from canals is estimated at approximately 84MW. Estuarine and coastal water temperatures are also favourable for heat extractionespecially in the south west and south of England. The saline water may allow for alonger operating window due to the decreased tendency for ice crystal formation.There are a number of limitations to those conclusions that must be borne in mind while readingthis report and viewing the NHM:6 Environmental designations and constraints have been added to the NHM layers forinformation. However, as with the design of any scheme, local issues would have to beinvestigated in more detail during a feasibility assessment. A simple comparison with the heat demand areas on the NHM has been undertaken.Aggregated demand totals (kWh) were compared with the largest river heat capacities(kW) in a qualitative sense. A more detailed comparison of heat demand against heatcapacity could be considered in the future. The non-consumptive nature of open loop abstraction and discharges means that waterresource stress is likely unaffected by the installation of heat pumps. However, therewill be local factors to consider if a large flow rate (abstraction and discharge) isproposed. The main constraint on extracting heat from waterbodies is the temperature limit andgradient at the heat exchanger. Mean winter temperatures calculated in this study aremostly in the 4 – 8 C range. This means there is likely to be only a small temperaturegradient in most cases and this will limit the size and efficiency of the heat pump. There is some uncertainty about utilisation and reliability due to variations in winterwater temperatures around the mean. Local temperature measurements and analysiswill need to be undertaken during scheme feasibility to understand these variations. This study is based on natural winter flow estimates. Many waterbodies may beinfluenced by non-natural abstractions and discharges that alter both flows andtemperatures. Recommendations for addressing some of these limitations have also been developedas part of this study, and can be found at the end of this report.

Water source heat map layerIntroductionBackgroundAs set out in the Government’s 2013 policy paper The Future of Heating, Meeting theChallenge4, wide scale deployment of heat pumps and heat networks are central to our visionfor the UK’s energy future. Alongside other low carbon forms of heating, they will play animportant part in safeguarding the UK’s future energy security and cutting greenhouse gasemissions.There is latent heat available in our rivers and canals, and in the seas that surround us. Many ofour towns and cities are located close to large water sources.Water source heat pumps operate by taking heat from water, boosting its temperature andfeeding it into local heat networks or single buildings. There are very few large scale watersource heat pumps in the UK, but there is significant potential in utilising water as a heat sourcein this way, to supply renewable heat at scale to our homes and businesses.High level water source heat mapDECC published a ‘high level’ water source heat map in August 2014. This map was producedto raise awareness of this potential heat source and provided an early estimate of the potentialof 49 English rivers, estuaries and from coastal sites.The output of this first heat map was indicative and has been used to differentiate betweenareas of higher or lower potential.Since August we have been developing a detailed map to produce a more robust estimate ofthe potential, and to integrate the map into the National Heat Map. The National Heat Map,which provides information on modelled estimates of annual heat demand, allows users toundertake initial investigations on modelled energy use at buildings and street level. Thissupports heat mapping by local authorities as part of an area-wide exploration of heat networkopportunities.Combining a detailed water resource map with the National Heat Map means that we can nowma