In the first of a series of blogs on net-zero carbon, Clare Wildfire, Global Practice Leader — Cities, from Mott MacDonald, explores the changes needed to meet the net-zero challenge.
In May last year the UK government legislated to cut greenhouse gas emissions to net-zero by 2050. It acted on advice and recommendations from its advisory group, the Committee on Climate Change (CCC), that rapid and total decarbonisation of the economy is required to achieve a stable climate and a sustainable future. In addition to recognising the UK’s need to play its fair part in decarbonising the entire global economy, the CCC and government noted that the UK’s net-zero target is realistic – and economically desirable.
The burning question is how to do it. The infrastructure and built environment industries have a big part to play. To date they have made some, limited, progress on doing what they do already in lower carbon ways. The CCC’s message is about transformative change in what we do as well as how we do it. New types of assets fit for a net-zero future will need to be brought online while other assets currently in use will have to be decommissioned or re-purposed. Plans for some new assets will need to be revised or scrapped.
Before the CCC spurred national government into action, the mayor had already started leading the way, setting in motion some of the most ambitious plans to tackle climate change in the world through the 2018 ‘Zero carbon London: a 1.5C compatible plan’.
Three strands of activity are required to meet the challenge. Firstly, we need to create a clean energy revolution. This will involve transforming the energy system, including how we produce and use energy. Renewable electricity is one of the game-changers (for example wind and solar generation). Other forms of low-carbon electricity generation, such as biomass and nuclear, and new forms of energy supply such as hydrogen, will play a part in the future energy mix too, helping displace fossil fuels as a primary energy source.
If electricity production can be decarbonised, many aspects of daily life can be changed, from the way we heat our houses to the way we travel.
London already has plans to electrify much of its transport network over the coming decades, together with an associated upgrade to its electricity network capacity. But, alongside the rest of the country, it has a challenge in how to decarbonise the heating of buildings. Heat is acknowledged to be one of the hardest net-zero challenges because natural gas is so dominant as a primary energy source. To decarbonise heat a decision is needed: whether to replace natural gas with hydrogen or electricity.
Secondly, decarbonising the energy system is a massive undertaking, with significant technical, political, social and economic challenges. But the scale can be reduced by curbing energy demand. The amount of new generating and transmission infrastructure required can be minimised if we step up efforts to improve energy efficiency – to make available power go further. This will involve radically transforming our approach to energy conservation in the design, construction and operation of assets.
Finally, it is now clear that it will not be possible (at least in the next half-century) to totally remove all functions that emit CO2 and what we can’t remove we will need to capture and store to stop it entering the atmosphere. The majority of scenarios for meeting the global 1.5°C target involve some level of CO2 sequestration, because they assume the global economy will not be able to transition away from fossil fuels fast enough. Sequestration options include land-use change, ecosystem restoration and reforestation, as well as technological solutions to capture and store carbon.
The UK has tackled the low hanging fruit for the first two strands with relative success. Net-zero has brought into focus the need for action on aspects that are more difficult. And it is only now that a net-zero target has been set that the significance of the third strand, capturing and storing carbon, is truly clear as the infrastructure industry is forced to consider how far it can really go in reducing its emissions to zero.
