‘Net zero’: the elephant in the room is the gas boiler in the basement

13 oct. 2021 5 Consumo de tiempo Read

Por Paul Feely

smart gas and water meter system

Many of our clients now have targets to achieve ‘net zero’ within their operations in the coming years, in line with the Government’s own target. Many of them have also realised that these targets won’t be achieved without reducing the emissions generated by the buildings that they own and occupy. And this, in turn, has led inexorably to the realisation that a significant barrier to the achievement of a ‘net zero’ carbon target is the gas (or oil) boiler in the basement.

There are quite a lot of these elephants in the room: according to the Committee on Climate Change, in 2015 space heating was easily the biggest single consumer of energy in the UK’s non-residential buildings, and two-thirds of it was powered by gas.

This means that whatever landlords do to reduce energy consumption, ‘net zero’ is simply not achievable unless they tackle the problem of how to heat their spaces.

Better insulation and proper building management are both part of the answer. But this alone is not enough, and changes to central heating systems are also required.

Some technologies are still ‘emerging’ and vary highly in their cost-effectiveness. Each has its own difficulties and may only work in some places, some of the time. Innovation will play a big part in this.

Buildings, like cars, are going electric. But electricity is normally significantly pricier than gas per kWh (notwithstanding current gas market turmoil). Electricity sourced from 100% renewables is even pricier. Options exist for making the best use of this resource and micro-generation. Let’s look at these.

  • Heat pumps (fridges in reverse) seem like a promising technology to us. But they are not yet terribly efficient at delivering hot water at the temperatures needed for many existing (older) central heating systems. Heat pumps work best at delivering lower water temperatures (40/50⁰C), whereas historically heating systems were designed to operate at 80⁰C so there’s an implication for retrofit solutions, which requires careful cost-benefit analysis. They require large footprints and can be noisy.
  • Problems of intermittent generation, and mismatches of supply and demand, from wind and solar power can be resolved through battery storage, but buildings are not always suitable for these technologies in the first place. (And for those who care about it, solar power has a much higher embodied carbon than wind power). So maybe burning something other than natural gas is the answer, such as biomass or hydrogen. Burning biomass produces emissions, may not be permissible in air quality control areas, and can be hit with delivery problems. Burning hydrogen is in its infancy as a technology and not widely available. It produces no emissions but there are concerns about its safety and cost-effectiveness, never mind how to deliver it at scale.

We find in our advice to clients that no one option is the outright winner, especially because the technological and regulatory landscape is constantly evolving. Rather, the best solution will depend on the circumstances of the individual building and is a balance of technical and commercial factors.

We try and strike that balance by:

  • Establishing the effect of the client’s own emissions reduction objectives, typically by using the CRREM model to establish when and in what circumstances a building becomes ‘off track’ in terms of delivering a ‘net zero’ goal. This can translate into phasing advice – it may be neither practical nor cost-effective to attempt to get to ‘net zero’ in one leap.
  • Testing and investigating building performance through thermal assessments, air pressure tests and thermographic surveys. We also identify options for the façade to limit solar gains and retain heat during winter periods.
  • Providing a full thermal model of the building, predicting energy consumption based operational data, and advising on the options for improvement. Among other things this can determine whether the predicted EPC for the building will meet minimum regulatory standards.
  • Designing and specifying suitable options, for central plant and infrastructure. This needs to consider (among other things) available space, acoustics, phasing, interfacing with existing services, building management systems, and of course cost.
  • Examining ways the cost can be reduced through government incentives, grants and the new Capital Allowances