This is a much harder question than for transport. Their are three options and their is no clear consensus amongst those experts I have spoken to.
What is worse is their are no clear pioneers in the UK with most projects being too small and most housebuilders being terrible power and heat suppliers (its not their bag). I can only think of Bicester Energy Centre as being a successful district heating urban expansion example and that has still not yet had an evaluation.
Their are basically three options:
- District Heating
- Ground or Air Source Heat Pumps.
Hydrogen could use with adaptation the existing gas networks serving 75% of households. The disadvantage is it is 3 times less energy efficient than ground source heat pumps. Also the energy density of hydrogen per unit volume is one third that of methane. So if we were to use it as a direct replacement, we will need three times more storage and distribution capacity than we currently have for methane, massive investment in tanks and gas mains would be needed. I cant see it being practical unless you use biogenic methane – which uses Algae to convert Co2 to Methane – overall carbon neutral. This so called ‘Renewable Natural Gas’ is so far more a proposal than a reality. The biggest problem however is the massive extra energy needed to produce Hydrogen. As 75% of energy is lost from conversion this alone would require UK electricity production to increase to roughly double to compensate.
District heating has potential but is much easier to do wit new developments and requires high density urban areas. The downside being the heavy insultation they require
Heat pumps have potential, but Guardian
because this technology works at a lower temperature than existing boilers, it requires many homes to be much better insulated, or to have larger radiators, capable of delivering more heating power. For those who have switched to heat-as-you-go combi boilers, it will necessitate the reinstallation of a hot water tank.
Their effectiveness however depends on the underlying geology. They are common in Jersey as it is built on granite. They also require electricity to run. However as they produce more heat than the electricity they consume recent modelling suggests no net increase in uk power requirements. The real challenge is upscaling – The Times
Overall heat pumps seem the most practical. Our housebuilders have poor knowledge of their use however and I have heard several horror storeys of bad installations which generated nothing. There are success storeys however, such as the 700 unit Wandsworth riverside proposal, some integrating with district heating especially at higher densities.
What will the role of planning be?
I see see a two stage process. One an ‘energy strategy’ stage done at masterplanning stage – as commonly happens in London. The second through building regs only where buildings have both to reach an energy use standard and a net zero use of carbon standard. There might also be an allowable solutions systems, as proposed and dropped a few years ago, for small residual emissions. Lets hope the Zero Carbon Hub fires up again.
However care would need to be taken that no land was included in any national scheme of treeplanting/habitat restoration as part of a national zero carbon plan.
One thought on “How will New Zero Carbon Communities Get their Heat and Power?”
District heating is a poor match for highly insulated new build housing, which requires very little energy for heating and should make the most of free heat from solar gain.Without swimming baths or other year round local demand, district heating is inefficient to run solely during the heating season. DH mains are at too low a temperature for domestic hot water and would need boosting, probably from an electrical element in the thermal store. All-electric houses may well be the best approach, allowing precise control via individual room thermostats. As the grid decarbonises, they would also have a decreasing carbon intensity.