What innovative solutions and materials are making the most significant contributions to achieving carbon-neutral construction projects? 

Climate change is a global priority, prompting nations to draft policies for mitigation. Notably, 40% of global CO2 emissions arise from the built environment, necessitating innovative solutions to reduce emissions from building operations and materials. In this month’s editor’s question, we ask: As the demand for energy-efficient buildings grows, what innovative solutions and materials are making the most significant contributions to achieving carbon-neutral construction projects? 

A team of researchers from Chung-Ang University in Korea are researching CCU processes that use waste materials or abundant natural resources as raw materials to ensure their economic feasibility. The team, led by Professor Sungho Yoon and Associate Professor Chul-Jin Lee, recently published a study where they discuss the utilisation of industrial CO2 and dolomite for the production of two commercially viable products: calcium formate and magnesium oxide. 

Using a catalyst to add hydrogen to CO2 resulted in Calcium formate, a cement additive, de-icing agent and animal feed additive and Magnesium oxide which is extensively used in the construction and pharmaceutical industries. The process was viable and extremely rapid, yielding the products in 5 minutes at room temperature, researchers also estimate this process could reduce global warming potential by 20% when compared to traditional calcium formate production methods.  

“Based on the results, we can say our method offers an eco-friendly CO2 conversion alternative that could replace the conventional approaches, potentially contributing to the reduction of industrial CO2 emissions,” Yoon explains.  

Our first response is Jon Bonnar, Co-Founder and Managing Director at Cotswold Energy Group, now part of South Coast Insulation Services (SCIS), the UK’s largest eco-installer, who believes CO2 heat pumps are a great alternative from traditional methods.  

“As the global demand for energy-efficient buildings continues to rise, it becomes imperative to explore innovative solutions and materials that can significantly contribute to achieving carbon-neutral construction projects. 

“Traditionally, many renewable heating systems, especially in commercial settings, have relied on Hydrofluorocarbons (HFCs) and Hydrofluoroolefins (HFOs). However, these synthetic chemicals have raised environmental concerns. HFCs in particular, are known for their high Global Warming Potential (GWP), leading to bans in various countries. HFOs were initially considered a more environmentally friendly alternative, now has raised alarms due to their potential to produce trifluoroacetic acid (TFA), which poses risks to both human health and the environment. 

“To address these challenges, a promising approach is to shift towards natural refrigerant-based heating systems. Currently, three viable natural refrigerants are dominating the market: ammonia, propane and carbon dioxide. In large commercial projects where diverse heating requirements are common, CO₂ heat pumps have emerged as a standout choice” 

We ask two more experts from Tunley Environmental and GeoPura, for their insights on how we can make carbon-neutral construction a reality. 

Nathan Wood, Carbon Reduction Scientist, PhD (Pending) and Dr Gareth Davies, Carbon Reduction Scientist, PhD at Tunley Environmental 

In recent years, the momentum behind carbon-neutral construction has noticeably increased. Governments, industry and consumers all recognise the need for a more sustainable approach to construction. This consensus is being supported by a growing body of guidance documents and standards designed to support the transition to Net Zero. For example, the Promoting Net Zero Carbon and Sustainability in Construction document published by the UK government in 2022.  

For construction projects, guidelines and standards such as PAS 2080, BREEAM, and LEED are becoming increasingly essential. PAS 2080 provides a framework for mitigating carbon emissions at every stage of an infrastructure project. It achieves this by setting targets and quantifying the emissions generated at each stage, thereby facilitating reductions against the quantified baseline. This is a well-regarded standard, the High Speed 2 (HS2) railway in England is being built to the PAS 2080 standard.  

In the specific context of buildings, BREEAM focuses on sustainability and environmental performance. Encouraging developers to go beyond minimum statutory requirements to create buildings that offer environmental, economic and social sustainability, and are subsequently scored using these metrics. LEED has the same lynchpin to its guidance, promoting water and energy efficiency, better indoor environmental quality, and resource stewardship. These initiatives frequently leverage high-efficiency HVAC systems, including variable refrigerant flow (VRF) systems and the adoption of energy-efficient LED lighting, often controlled through smart systems to minimise electricity consumption. 

Technologies such as ground-source heat pumps, which harness the Earth’s consistent temperature to facilitate efficient heating and cooling, are also gaining traction, particularly in the context of heating and cooling domestic housing. Moreover, the careful selection of sustainable building materials plays a key role in reducing the carbon footprint of a building. A major part of the movement towards carbon neutrality in construction is the use of sustainable materials. With a major focus on low-carbon concrete and recycled steel. As these materials often make up the majority of a buildings carbon footprint, targeting these materials is critical to reducing the carbon footprint of a building. Indeed, globally 8% of CO₂ emissions are a result of concrete use.  

To conclude, conducting a Life Cycle Assessment (LCA) to monitor the carbon footprint throughout the construction stages of a project is fundamental for achieving carbon-neutral construction. This provides an analysis of a building’s environmental footprint and facilitates the integration of initiatives designed to minimise the carbon footprint to the greatest extent possible. 

Ian Wilkinson, Chief Operating Officer, GeoPura  

As construction projects aim for carbon neutrality, one of the critical challenges is decarbonising off-grid power. Diesel generators have traditionally provided the necessary power construction sites require, especially in the early stages of a project, but have brought along environmental and sustainability issues that make them unsuitable. They emit greenhouse gases like CO2, NOx and particulate matter, contributing to air pollution, climate change and creating health risks for workers and nearby communities. 

There are several ways to decarbonise off-grid power, such as HVO or biodiesel replacements, battery-powered generators and temporary solar arrays. But in many cases, these options offer minimal reductions in greenhouse gasses, still emit particulates that impact air quality or don’t provide enough reliable power output for the whole of a construction site. 

A more suitable solution for construction sites is hydrogen-powered generators, like GeoPura’s HPU, offering energy-dense, 100% renewable, zero-emission power. GeoPura harness renewable energy sources such as wind and solar to produce hydrogen fuel through electrolysis, and then convert this fuel to electricity via hydrogen fuel cells in its HPUs, thereby generating off-grid power with zero harmful emissions. This innovation eliminates the carbon footprint associated with diesel generators, drastically reducing greenhouse gas emissions and improving air quality on construction sites. 

To get closer to carbon neutrality, construction projects are also electrifying their site vehicles, which is difficult without a grid connection. GeoPura’s HPU can support high-speed electric vehicle (EV) charging, along with combined heat and power (CHP) for on-site welfare units from a zero-emission source. A notable example of this multi-purpose use in the sector is at the Viking Link Interconnector site. This installation delivered critical electrical power, heating and hot water to construction facilities while also powering onsite EV charging points. Operating autonomously, the HPU replaced the need for diesel generators, resulting in a substantial reduction in carbon emissions, estimated at a tonne of CO2 saved each week. 

Construction sites often operate in low-emission zones or need to meet stringent environmental standards, such as noise pollution regulations, to minimise the impact on nearby communities. The HPU is a hundred times less noise intense than equally sized diesel generators and can help secure approvals for works by reducing harmful emissions. 

Embracing hydrogen-powered generators enables construction companies to meet their sustainability objectives and establish a new benchmark for responsible and environmentally conscious building practices.