11 Apr 2016
NETWORKS MATTER - GET TO KNOW DISTRICT ENERGY
Conceived over 100 years ago, district energy systems that link buildings using a network of heating pipes are now gaining traction as an energy-efficient solution for urban and rural areas District Energy can be described as the linking of two or more buildings together via a network of heating pipes from one or possibly more heat sources. It encompasses both heating and cooling networks, with the latter often being used in city centres for air conditioning. There are four key components that make up a District Energy scheme. Firstly, you require a source of heat, which can range from Waste Heat from Industry to Geothermal and even Biomass. This is then passed through what is known as the Distribution System, which is most commonly a network of pipes that are buried underground. The water must then past through a Consumer Interface, this could be in the form of a HUI (Heat Interface Unit), a Thermal Substation and Metering Station, before finally reaching the Customer, whether this is a housing development, school, leisure centre or an office block. Whilst the origins of District Energy can be traced back to well over 100 years ago, it failed to gather any serious momentum in the UK until the 1960’s and early 1970’s. It was at this time when this method of delivering heating to homes and businesses was seen as the way forward for all urban areas. The Government seemed to agree as, in 1971, they published a detailed guide for local authorities informing them how to secure an efficient and cost effective heat network for themselves. However, in 2015, only 2% of homes in the UK were heated through the use of District Energy networks. The reason that District Energy has yet to take off in the UK is ultimately down to a number of factors, including the very poor piping systems and installation standards that were prevailing in the early 1970’s. Coupling these with a lack of understanding regarding water treatment, how to design and control networks it is not surprising that many failed and were subsequently removed to make way for individual gas fired boilers. Thankfully, all of these issues are all now well understood and should not exist on any network built since the new wave of systems started in the late 1980’s. Furthermore, there is even now an industry Code of Practice, setting standards for what is required to deliver an efficient, reliable and long lasting network. However, despite these early setbacks, there are still some clear advantages to District Energy. Firstly, using a District Energy network can bring economies of scale that a single building cannot deliver; it captures the potential to use low carbon heat sources on a wider scale. These schemes can also use many different energy sources including waste energy, either being waste heat from industry or Energy from Waste facilities. As well as the standard biomass wood boiler, other sources of energy include Gas fired CHP, geothermal energy and either ground or water source water pumps. These wide ranges of energy sources allow District Energy projects to be some of the most innovative and diverse schemes of modern times. In addition, connecting buildings together with differing energy demand profiles, i.e. dwellings and offices can present a flatter demand profile, which is more efficient for most heat sources, whilst these schemes can also deliver operating cost savings on a whole life basis. So, by now you must be wondering why District Energy has yet to make any sort of significant progress in the UK, and that it must surely now be only a matter of time before it has its long awaited moment in the spotlight? Well, as it turns out the Government are clearly in agreement as, in last November, they announced over £300m of funding for heat networks in the next five years. The specific funding allocation of £320m is expected to draw in up to £2billlion of additional capital investment and lead to the construction of hundreds of heat networks in urban and rural areas of England and Wales. A Pilot Scheme has now been launched and they are now accepting applications from Local Authorities and other public sector bodies this autumn. So after all this time spent waiting in the shadows, it is finally time for District Energy to deliver on its promises, and hopefully not simply run out of steam?