Expedition’s Energy Infrastructure expert Daniel Raymond reflects on decarbonisation and planning for the energy transition.
Gas Combined Heat and Power (CHP), rightly or wrongly, has for a long time been the go to approach for delivering CO2 emissions savings against conventional generation. Its ability to bypass the use of traditionally carbon intensive grid electricity has meant it was heavily promoted by National Policy and particularly the current London Plan, as a way of meeting our carbon commitments.
However, like many in our industry I have often felt an uneasiness with the sometimes blinkered roll out of gas CHP just to meet planning conditions. In part because, as we know all too well, CHP requires a set of particular conditions to operate as intended; but even more so, because the electricity grid, which gas CHP has been betting against all this time, has been getting cleaner.
Decarbonisation of the grid always meant that gas CHP would be a time limited technology.
With continued investment in renewable energy to supply our electricity grid, it has been decarbonising, and is something we no longer want to avoid. While it is fair to say decarbonisation has happened quicker than some had anticipated, it was never so far off that it’s implications shouldn’t have been considered. However, what we are finding is that energy systems haven’t been designed to accommodate a shift away from gas CHP and are instead locked into a carbon intensive future.
It is, therefore, welcoming to see that the Draft New London Plan has shifted to reflect this context, demoting the use of CHP and promoting electrically led heat pump technology, which can now produce heat with a lower carbon content. However, policy needs to be mindful of not falling into the same trap of promoting a new ‘golden’ technology as it has done with CHP and before that biomass boilers. It is clear one solution doesn’t fit all.
We are also encouraged by the possibilities that new development offers as the ideal testing ground for a clean electric future, especially given their fabric performance. This is certainly not the place for the continual promotion of heat loving CHP.
What does this mean for District Heat Networks?
So, is there a future role for site-wide networks without CHP? Our research shows that heat pump solutions don’t generally lend themselves to a district network approach. Block level ‘community’ networks can provide sufficient diversity to reduce peak demand and plant size, without incurring the costs and losses of a larger site-wide network. These additional costs outweigh the minimal carbon benefit, unless you can tap into a source of waste heat from industrial or commercial activities or the tube or sewer network. In these instances, an ambient loop running at low temperature serving multiple properties could be an effective solution. However, some of these waste heat sources are extremely difficult to exploit because of the risks associated with working in the ground.
So how do we transition to an electric future?
The UK Industrial Strategy promotes a shift towards a dynamic grid – any solution needs to be compatible with that shift and avoid overloading the Grid. We can envisage how new developments can play a role in offering storage to enable this transition, with smart community battery installations, linked to photovoltaics, electric vehicles and heat pumps. Further heat pumps coupled with thermal storage can take advantage of cheaper off-peak electricity, operating at night, and storing heat for use in the day. An intelligent system of this kind would be enabled and managed by smart controls and metering.
It is fair to say that decarbonisation brings us several new options and while the Draft New London Plan is looking to address these it should be mindful of our ultimate objective: to provide affordable, reliable, clean energy, not promote particular technologies.
At Expedition, we have begun to explore, from a whole life perspective, a variety of system solutions for meeting this mission, alongside the zero carbon targets supported by policy.