CHP: What does the industry actually think?

27 October 2015

Last week Bill Watts, senior partner at Max Fordham, made the assertion that there was “growing disquiet surrounding the installation of Combined Heat and Power (CHP) and district heating systems”.

The subject prompted a flurry of emails and comments, with some supporting Watts’ position, while others argued that CHP and district heating systems have an important role to play in delivering energy efficient building.

Here the industry responds to Watts’ article.

Crispin Matson, country manager, Ramboll Energy UK

I think the situation is slightly more nuanced than Bill’s position. However, his points are slightly academic as the long-term aim is to build up district heating systems that can be connected to whatever power is most appropriate.

Ramboll are very much involved with district heating and the systems can be very carbon efficient. I don't disagree that gas-fired CHP is not necessarily as efficient as is claimed, it may only be slightly better than gas-fired individual boilers. What we should be looking at is district heat systems powered by waste to energy plants and large-scale heat pumps.

We are currently working on a scheme just outside the City of London where we are upgrading the heat from a London Underground exhaust vent using a heat pump. Where low grade waste heat can be combined with heat pumps, then distributed across developments, very efficient systems can be created. As the grid decarbonises, this power can be used to drive large-scale heat pumps.

The London plan is going in the right direction by ensuring that developments have centralised plant rooms. It may encourage CHP in the short-term, but the district heating systems can be powered by other means in the future.

As far as regulation goes the Association for Decentralised Energy (ADE) has just written a new code of practice for CHP. I don’t think that they have a remit to measure effectiveness of CHP, but that body could easily take up that role. When there was the same argument about the efficiency of heat pumps the BRE carried out some research and this cleared up the situation. Possibly they could carry out a similar role for CHP. Of course this would depend on someone's desire to do this and pay for it.

Reginald Brown, head of energy & environment, BSRIA

There is no doubt that under the right circumstances district heating based on CHP can provide a low carbon solution to heating and hot water provision in residential neighbourhoods. The BSRIA view is that proposed schemes and connections to existing schemes should be properly evaluated on the basis of economic and environmental viability. If GLA did not have a policy of encouraging developers to at least consider the district heating options then few might bother. Our experience suggests that GLA are open to rational discussion and provided that all the options are properly considered they don’t force the adoption of district heating where it would not make practical sense.  

It should not be surprising that if developers and consultants grudgingly adopt a minimalist CHP/district heating solution simply to get through planning they won’t get an optimum system for the end user.  There are undoubtedly significant hurdles to overcome in providing good and effective chp/district heating scheme, not least of which is the lack of tried and trusted design expertise.  BSRIA and UKDEA are currently working with the district heating industry to produce a Heat Networks Design Guide that will provide practical guidance to help designers produce effective and efficient systems that do make economic and environmental sense.  This should be published in July 2016.

Aimee Betts-Charalambous, policy officer, Association for Decentralised Energy (ADE)

Mr Watts appears to suggest that only one solution, ultra-low energy buildings, are the answer. I would suggest that a combination of answers are needed. New buildings should be more efficient than they are – it is the cheapest way for the energy customers in those buildings. But seeking to deliver all heat policy through one tool, however, is not backed up by evidence – something that was rather lacking in his criticism of the sector.

The benefits of using CHP within our energy system are well documented. Through the CHP Quality Assurance scheme, operators must provide annual performance data to qualify as “good quality CHP”, ensuring fiscal benefits are in line with environmental performance. There is no requirement on any other technology to demonstrate its in-use performance in such a way. This applies to building efficiency like insulation and generation technology like boilers and heat pumps.

The unfounded allegation that district heating is a more expensive solution than very high levels of insulated buildings is not backed by recent academic research (Heat Roadmap Europe), which shows that while reducing heat demand through building efficiency improvements is vital, it only provides value up to a certain point. From then, the decarbonisation of heat supply becomes more cost-effective than additional passive efficiency measures.

District heating can therefore be a key tool in delivering a low carbon economy, and that is why it is recognised as such by trusted expert organisations from the Energy Technologies Institute and the Climate Change Committee.

The ability of heat networks to decarbonise over time is already being seen in the UK and abroad. UK networks such as Pimlico have moved from coal to oil to gas CHP, and in the future could use heat pumps to meet demand. In Islington, an extension to the Bunhill Heat and Power network is planned to capture waste heat from the underground.

The waste heat potential within London is massive, with a number of different projects utilising water source heat pumps and waste incineration. A recent study by Buro Happold found that by using heat pumps to deliver heat at 70°C, waste heat could be used to deliver more than the cities total heat demand.

By developing heat networks the source of waste heat can be linked to the point of heat demand. With a power generation sector that loses more than half of its energy as waste heat, the existence of heat sources is not the issue.

Marko Cosic, technical director, COHEAT

I think Bill needs to pick his targets better and stop throwing rocks at his allies in the world of energy efficiency. The problem is not with CHP or district heating, it is the system that planners are using to determine what is energy efficient and this is flawed.

The Standard Assessment Procedure (SAP) only cares about marginal fuel use and doesn’t take into account capital costs or maintenance costs – this is the same for insulation, thermal bridging, ventilation, and air tightness. If we want to have more efficient buildings we need to give planners the tools to be able to make better decisions. The SAP needs to be revised so that it is calculated over a 30-year timescale and not solely based on marginal cost and emissions.

Phil Jones, chair of CIBSE CHP & DHP groups

If heat networks are to form a significant part of our future low-carbon energy infrastructure in the UK then they need to be designed, built and operated to a high quality to deliver customer satisfaction. We have developed a code [with the Association for Decentralised Energy (ADE)] to assist in achieving that aim by raising standards right across the supply chain.

Setting minimum (and best practice) standards should provide greater confidence for specifiers and developers. This code can also be included in the tendering/contracting process to specify minimum requirements for a project.

The adoption of this code of practice by developers could ultimately be used to support marketing by providing assurance to customers and property purchasers that the heat network scheme has followed a set of design, installation and commissioning standards. The assurance provided by these standards should therefore have a significant effect on the heat network market.


Well I'm bowled over by the careful analysis of the detailed test results from heat schemes used to substantiate these points.

I suppose that makes all of this a dead heat ( excuse the pun) with Bill Watts article

Steve Harper, 2 November 2015

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