Net-Zero Targets Will Be A Real Problem For Property, Unless We Design Buildings Differently

If commercial real estate isn’t designed to be net-zero carbon, then landlords and developers risk having stranded assets at a high cost to their bottom line and the planet. On top of that, the reality of creating a net-zero-carbon building is a huge leap from what designers and building regulations have been assuming.

This is the message from engineering firm WSP’s Head of Net Zero and Sustainability for Building Services Kate Dougherty. The firm works across the entire real estate spectrum, and what Dougherty is seeing is that property developers need to move away from designing for compliance to designing for what really needs to be done to cut the UK’s carbon emissions. On the plus side, WSP is uncovering ways to do just this.

“This is a massive challenge and it will be frantic as time is running out, but it’s absolutely possible,” Dougherty said. “We’ve got the tools. Now we need to upskill and create a cultural change on all levels to design differently.”

Outdated Designs And Regulations

The need to create sustainable real estate is increasingly recognised. The challenge is what to do about it, Dougherty said. While planned developments can be redesigned before they are constructed, refurbishments are harder to carry out and will be costly.

In July, Jefferies downgraded British Land and LandSec from ‘buy’ to ‘hold’ in light of weak energy performance data across their portfolios. It estimated that more than 70% of their portfolios fall short of new minimum energy standards, which could lead to ‘greening’ costs of £700M-£800M.

However, net-zero-carbon energy use intensity targets are challenging and do not align with current practice.

“The net-zero-carbon energy use intensity target for offices is about 55 kilowatt hours per square metre, but our current industry standard is around 225 kilowatt per square metre,” she said. “So there’s a huge gap between what we have been doing and what we need to do.”

The other piece of the problem is the performance gap, said Dougherty — how the design intent in terms of energy efficiency differs from how the building really performs. She attributed the performance gap to several factors.

Firstly, weak building regulations. ‘Part L’ that deals with energy efficiency only looks at regulated energy, such as heating and lighting, and misses out unregulated energy use such as operating the lift and plug socket loads.

“The industry used to do detailed energy use modelling and part L modelling for compliance, but at some point we stopped doing detailed modelling,” Dougherty said. “That compliance method is massively removed from the reality of how a building operates. The targets are getting toward net-zero carbon, but the method is not.”

A second factor is a lack of performance data. Once a building is operational, there is little drive to measure energy performance, Dougherty said. Designers need that performance data to improve modelling for the next building and building managers need it to drive improvement.

“We need to do post-occupancy reviews," she said. "If this were done, data could be shared with the industry to allow people to design better and with the market to influence investment decisions.”

The Way To Create Net Zero Carbon Buildings

The first solution, Dougherty said, is to take a different approach to building design. The ambition to achieve net-zero carbon has combined with Covid-19 to cause a radical rethink in how space is used and WSP is working on several initiatives.

“We need to look at free cooling and underfloor air distribution, for example,” Dougherty said. “In the UK we could provide free cooling for 80% of the year, because this is how often the outside air is cooler than inside. You can’t just open a window as that’s uncontrolled.”

As well as physical redesigns, however, the most important way to create sustainable space is to challenge expectations. What people have come to expect from an office is not compatible with net zero carbon.

“We’re used to building a big shiny box, filling it with people, specifying tight temperature bands and lighting that is consistent across the whole floorplate and ensuring we don’t wait 30 seconds for a lift,” Dougherty said. “We need to be flexible and see where this brief conflicts with energy efficiency. We can make huge savings by using wider temperature bands and wearing a jumper, for example, or using task lighting.”

The second solution is to design for performance rather than compliance. WSP has embraced Nabers UK, an accreditation scheme born in Australia that focuses on the operational energy performance of an office. Its rigorous approach asks designers to create highly detailed models of how a building will perform then, once complete, compares performance back to these models.

WSP is working on a premium office scheme in London, helping the client achieve one of the first large buildings to receive Nabers UK accreditation. The project has generated results that could be adopted across the industry, Dougherty said.

“For example, by introducing CO2 sensors we have reduced the energy consumption of air handling units by a third,” Dougherty said. “Similarly, we gained a great insight into designing for peak conditions. Normally, designers look at the highest and lowest outdoor temperatures to create a model, but these conditions only occur 1% of the time. We needed to focus on designing systems to be as efficient as possible in normal conditions and have separate equipment to use in peak conditions.”

Though specifically for offices, Dougherty believed that Nabers’ approach heralds a very different way of thinking for all buildings. WSP has invested heavily in upskilling its team to carry out this detailed modelling. To get any closer to the UK’s target of net-zero carbon, more building designers might start to follow suit. And as Dougherty said, there is lots to be done.

This article was produced in collaboration between WSP and Studio B. Bisnow news staff was not involved in the production of this content.

Studio B is Bisnow’s in-house content and design studio. To learn more about how Studio B can help your team, reach out to studio@bisnow.com.