National Planning Policy Framework changes - Concrete ideas on decarbonising house-building

Last week, the new government set out the changes that it planned to make to the National Planning Policy Framework to facilitate the delivery of its five-year 1.5 million housebuilding target. Whilst the devil will be in the detail, anything that loosens the various chains on bringing forward more houses, whether private, affordable and/or rental (or all shades), will be welcomed by both industry and (generally speaking) those looking to get on the housing ladder or move up it. 

Balancing housebuilding with net zero aspirations

In the same context, of course, is that the UK is pressing towards its net zero targets. The UK Green Buildings Council “Net Zero Whole Life Carbon Roadmap” (Net Zero Whole Life Carbon Roadmap | UKGBC) indicates that the built environment in the UK is responsible for 25% of all emissions, with embodied carbon alone responsible for 5%. This of course extends beyond housing into all forms of construction, though it does not include any carbon emissions arising from the operation energy use of buildings. 

So, if there is to be a push for more houses (and therefore more construction) what can be done to try and mitigate any carbon emissions and the ensuing impact that would have on the environment? This shouldn’t be seen as an opportunity to “beat up” the housing industry – the industry is already bearing the cost and responsibility for nutrient neutrality, biodiversity net gain, the recent high costs of materials and many other matters. Nor should it be used to squeeze land values, which risks driving landowners out of the market.

Innovative approaches to sustainable construction

The question that could be asked, however, is there a way of delivering new construction in a way that doesn’t just rely on “business as usual”?  There are some examples of companies starting to take matters in hand. Vistry, for example, has relaunched its timber frame factory in the East Midlands (Vistry Relaunches Timber Frame Factory in East Midlands | Vistry Group). Another example is the £1bn joint venture between developer, Bywater Properties and Japanese forestry concern, Sumitomo Forestries (Bywater and Sumitomo form £1bn timber jv | EG News (egi.co.uk)), established to develop offices with timber structures.

The persistence of traditional materials: Steel and concrete's environmental impact  

Nevertheless, it seems likely that the industry will continue to rely on steel and concrete in construction.  Hannah Ritchie (How to decarbonise the world’s cement - by Hannah Ritchie (sustainabilitybynumbers.com)) in the excellent “Sustainability by numbers” blog (Sustainability by numbers | Hannah Ritchie | Substack) for example has written about the challenge of decarbonising the world’s cement (responsible globally for approximately 7% of the worlds CO2 emissions).  This was a follow up to an article on the green premium of changes in production for cement and steel, which is well worth a read (Could low-carbon cement and steel be cheaper than we think? (sustainabilitybynumbers.com)). The carbon issues from the use of cement would typically be seen as something  “hard to abate” (an expression that Akshat Rathi in Bloomberg (Cheaper Climate Solutions Mean It's Time to Retire 'Hard to Abate' - Bloomberg) suggests should be retired.  Hard to abate extends beyond cement to cover sectors such as steel, chemicals and trucking (so the drivers of the supply chain and some of the products being moved by the construction industry).  Rathi suggests that “hard to abate” can imply a lack of technology, prohibitive costs or lack or regulatory incentive. It has been suggested that industries use the expression to avoid taking action on climate change. After all, if it is too expensive to change methods of production (which costs are then passed on to either end-user or original landowner, limiting either the land or housing market) then there will be reduced appetite for change. Again, this isn’t a criticism of industry. In a functioning market, everyone responds to incentives (whether financial or regulatory) and it’s not in anyone’s interests to be seeking to deny climate change is a very real problem.

Technological innovations and strategies for reducing cement emissions

What Rathi argues is that technologies (such as carbon capture and storage (CCS) , electrolysis for steel production), alternative raw materials for cement and green hydrogen are all available to cut emissions. Focusing specifically on cement, Ritchie identifies three strategies, which echo the alternatives referred to in Rathi’s article:

• reducing the amount of cement used by substituting with supplemental cementitious materials (SCMs).
• retaining the current production process but incorporating CCS; and
• developing new processes for making cement that don’t rely on limestone thereby avoiding the CO2 by-product.

Overcoming Obstacles: Regulation, Investment, and Policy Support

Each alternative has a possible issue: SCMs are hindered by construction regulations and building codes. CCS is technically feasible but hindered by high cost and incomplete capture rates and the use of alternative source rocks are at an early stage of research/use (though see for example Brimstone | Deeply Decarbonized Cement). The cost may limit the market as suggested above, but more generally this obstacles for development and adoption lead to calls for more investment, policy support (and yes, effective regulation, whether boosting or relaxing where fair and appropriate) and strategic partnerships to reduce costs. 

It is easy to fall back on the law of unintended consequences. As the various stakeholders in the housing market grapple with new planning rules (and whether they will deliver the required outcomes without additional planning officer, the means of getting plan/policy compliant proposals past incalcitrant planning committees) and landowners and end-users alike consider the impacts of sustainability in their decision making, it is important to ensure that the steps taken to address the housing crisis don’t exacerbate the climate emergency in otherwise trying to do the right thing.