Chasing Zero

With the UK recently committing to net zero UK carbon emissions by 2050, sustainability expert, Emily Loquidis discusses the latest industry innovations and trends and how they might help drive change across the construction process and meet the required climate change targets.

 In June 2019, the British government committed to achieve net zero emissions by 2050, making the UK the first major economy to embed the target into law. In addition to work by the UK’s official Committee on Climate Change (CCC), this commitment follows recommendations from the latest Intergovernmental Panel on Climate Change (IPCC) report.

The IPCC concluded that, “Building emissions [have] to be reduced by 80-90 per cent by 2050…” and that, “New construction [has] to be fossil-free and near-zero energy by 2020…” to limit global temperatures to a 1.5°C increase and avoid the worse impacts of climate change.

And, globally, the World Green Building Council has set a target for all buildings to be net zero carbon by 2050, in line with the Paris Agreement’s climate change goals.

Here, we discuss what AECOM sees as four of the most important, recent industry trends and innovations that could help designers, developers, owners, and occupiers take the significant strides we need to achieve essential emission targets.

1/ Defining net zero

One of the most pervasive challenges in pursuing net zero goals has been defining what exactly the term means. To help address this, as part of a Net Zero task group convened by the UK Green Building Council, AECOM and other practitioners contributed to the recently published, A Framework Definition for Net Zero Carbon Buildings.

The framework aims to provide the industry with an agreed definition of what it means to be ‘net zero carbon’ both in construction and operation. This includes that net zero buildings should: promote deep energy efficiency through design; develop supply solutions based on on-site renewable energy and off-site renewable supply, and lastly pursue an offset policy.

The framework also encourages the industry to consider the whole lifecycle carbon of buildings when determining a building’s true carbon footprint. Crucially, it is designed to evolve, with the definition expanding to include more technical detail and performance targets.

2/ Looking at the whole picture

 Across projects, when it comes to achieving net zero, scale is our friend. We need to look beyond just one building or development to see how it fits within the wider ecosystem. This includes the infrastructure that serves buildings, nearby communities and neighbourhoods, and the connections that underpin them.

A net zero community should take a long-term investment view and will need to look at ESCo-type models that create incentives to invest in energy efficiency and low carbon technologies over a longer period of 20-50 years.

Connecting resource flows between buildings and levelling out supply and demand through virtual platforms is a novel answer to implementing net zero at scale. Connector technologies like Blockchain, enable the mapping of transactions and create a platform to facilitate peer-to-peer trading that could turn consumers also into producers or “prosumers.”

3/ Verifying performance

 Transparency and consolidation of data around net zero buildings is an important feedback loop to the larger market to shift transformation to a zero-carbon status. Voluntary net zero certification can set, accelerate and stimulate further market transformation.

The Living Future Institute’s Net Zero Energy and Carbon Building Certification programmes — which are components of the Living Building Challenge — are examples of such voluntary certification schemes.

The Living Building Challenge is built around two core rules, “All imperatives are mandatory,” and “Certification is based on actual, rather than modelled or anticipated performance.”

For example, as part of its matrix, the Living Building Challenge bans combustion, such as traditional boilers, biomass and combined heat and power (CHP) systems.

With other Green Building Councils and global NGOs developing and launching their own standards, practitioners will have an increasing range of tools with which to work.

4/ Embracing new positive paradigms

Because of this work, we will also hopefully see more innovative projects — such as the Bullitt Center, a Living Building Challenge six-storey commercial office building — emerge as exemplars and shape new positive paradigms.

Surpassing its design target of 50 kWh/m²/year, according to its measured energy performance, the Bullitt Center has achieved an almost 78 per cent reduction in energy usage compared to a neighbouring, recognised best-practice building in Seattle.

In addition to taking a whole eco-system approach, mapping resource flows and determining how waste from one system can be reused by another, the project team identified several new principles and approaches that can be adopted across the wider industry. The lessons learnt include a need to:

  • Deploy passive energy-efficiency strategies to leverage the capabilities of the building envelope and drive down demand.
  • Design out complexity and use hi-tech solutions that do not require layers of technology to achieve the desired outcome.
  • Incorporate innovative heating, ventilation and air conditioning solutions that decouple ventilation from space conditioning and reduce fan energy.
  • Focus increased, ongoing attention on tuning controls in response to performance monitoring and building feedback.
  • Integrate renewable and low carbon technologies, waste heat recovery and energy storage within the build.
  • Recognise that occupant interaction with the building is critical to achieving net zero status in operation.
NASA Ames Research Centre — Towards Net Zero Energy

AECOM Inc. Los Angeles California implemented net zero design best practice on the Sustainability Base at NASA’s Ames Research Centre.

Net Zero - NASA Ames Research Center
NASA’s Ames Research Centre, AECOM (photography: David Lloyd)

The Sustainability Base is supported by “exoskeleton” structural supports on the outside of the building that allow an unobstructed flow of air and daylight. The narrow width also facilitates cross ventilation through operable windows and night flushing.

The electrical power required for the building is more than offset by on-site photovoltaic solar panels and solid oxide fuel cell technology from a Bloom Energy Box, an example of repurposed NASA space technology. The site also features 106 geothermal wells supporting a ground-source heat pump system. The project achieved LEED Platinum and is verifying net zero status through operational data.