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By 2050, more than two-thirds of the world population will live in urban areas. By the same year, the UK Government aims to have reached net zero. As more governments around the world take steps against the climate crisis, it becomes increasingly important to understand and implement technologies that allow for development in sustainable and ecologically viable ways.

As demand for urban housing and public spaces increases, architects and developers must prioritize reducing CO2 emissions during the design, construction, and subsequent operation phases of new builds. But operational carbon must not be forgotten as so much of the work to reach net-zero depends on the retrofitting of existing buildings. Operational carbon accounts for more than a quarter (28%) of global greenhouse gas emissions.

What is embodied vs operational carbon?

Understanding the difference between embodied and operational carbon is crucial when planning and designing greener alternatives for your buildings. The two can be considered in much the same way as capital expenditure and operational expenditure in finance.

Embodied carbon is all the CO2 emitted in the production of the building. Much like CAPEX, embodied carbon is a result of distinct, rather than ongoing, processes that produce carbon. This includes the extraction and production of materials used during construction and their transportation in addition to the carbon released by plants and machinery throughout the building process itself. In the case of rebuilds, demolition adds to the embodied carbon of a site.

Operational carbon, like OPEX, is the carbon released from the ongoing operation of the building. Sources will include lighting, power, heating, ventilation, air conditioning, and other infrastructure such as lifts and automatic doors.

Improving carbon emissions: embodied vs operational

In recent years, much attention has fallen on improving operational carbon and some huge leaps have been made. Basics like improving building insulation and installing LED lighting and automatic controls have long been used to improve energy efficiency. These are proven mitigators and can lower OPEX for many sites, though it should be noted that they still add to the embodied carbon of the site as new products and materials are brought in, and old ones removed and disposed of.

Embodied carbon can be reduced during the initial design and planning stages, but cannot be removed from an existing building. Reducing embodied carbon is only achieved by thoughtful initial design and specifying construction products and materials that are more locally available, extracted, manufactured, and delivered via low-carbon means. This should include minimizing energy use and reducing waste through recycling wherever possible. Using materials and products with longer lifespans and more resilience to change will reduce future carbon impact. It can be well worthwhile working with an expert in sustainable building design.

Rebuild vs retrofit

As the climate crisis has moved further up the agenda, many organizations have set their own green targets alongside the UK target of net-zero. With emissions from buildings forming such a high proportion of carbon, improving their efficiency is a crucial contributor. This has sparked much debate surrounding the value of incentivizing retrofit vs demolition and rebuild.

New buildings are typically designed to be highly energy-efficient, with innovative materials and using modern construction methods as well as smart technology. This combines to significantly reduce operational carbon as well as OPEX for the owner and occupier. Retrofitting existing buildings to save energy and cut carbon, by comparison, can be more complex and time-consuming with resultant compromises, so newbuilds are considered more attractive by many. Notwithstanding the tax-efficient financial incentives that exist, too.

However, for organizations concerned with their green credentials, embodied carbon is top of mind. All of the energy and carbon involved in demolishing a site and disposing of materials, whether as waste or recycling, adds to the embodied carbon within the existing structure itself. All that before the new building project even begins can be a huge amount of carbon to consider.

Refurbishing existing buildings will clearly save energy and cut carbon, although installing better insulation or replacing and upgrading old systems will increase the embodied carbon, but it will be insignificant compared to the carbon impact of demolishing and rebuilding. Retrofit measures extend the life of any building which will contribute significantly to our net-zero objectives.

Cutting carbon

Simple and consistent changes can make a significant contribution towards saving energy and cutting carbon. Installing LED lighting rather than traditional lamps or using underfloor heating can reduce energy consumption and emissions. Equally, using renewable energy heat pumps, which extract the buildings’ heating or cooling requirement from the external ground, air, or water, will substantially reduce the environmental impact. Heat pumps can also be used in centralized, community heating schemes. Transforming the way we heat and cool our buildings is a vital component of the journey to zero carbon and there are a number of effective technologies that developers could be investing in now.

If we want to see widespread adoption of renewable options, it is important that we look at extending vital renewable energy incentives such as the Non-Domestic Renewable Heat Incentive (RHI). Sadly, the RHI is no longer accepting applications. In its place, the government has introduced the Clean Heat Grant. Of course, in prime residencies, incentives will need to look a little different.

The vast array of benefits of going green

With every organization talking about moving to more sustainable processes, this might seem like an unnecessary question. But improving emissions can be a costly project and will often see its biggest returns in the long term. Therefore, short-term recognition can be the added boost that many companies need to push them to engage fully with greener practices.

There are many widely recognized accreditations that can set a site apart. The Building Research Establishment Environmental Assessment Method (BREEAM) is a leading sustainability assessment for buildings and infrastructure. The Leadership in Energy and Environmental Design (LEED) is an international verification of a building’s green features. SKA Rating is an environmental assessment method and benchmark for non-domestic fit-outs, led by RICS.

As some of the most renowned accreditations, the bar for these is high so your building project or retrofit is certain to stand out.

Why does it matter?

The net-zero race is on. Yet, the key to decreasing the built environment’s impact on climate change is to reduce carbon emissions. To achieve long-term benefits, the whole lifecycle of a building must be taken into consideration. Therefore, truly understanding the difference between embodied and operational carbon is crucial when considering a site’s carbon footprint.

Understanding the complex processes from design through to procurement and installation, to operation and end-of-life and the resulting emissions is a crucial step in making better, greener choices for projects in the built environment. The sector has an opportunity in the coming decade to lead the way to a more sustainable future, but this intention must start at the point of design and continue through the lifecycle of a building. We can change the way people are living and experiencing their environment for the better. It is a complex process and businesses need to be in it for the long haul, but it is, unquestionably, the way forward.

About the author:

Steve McGregor joined DMA Group in February 2016. He is a highly experienced sales and general management executive with a strong 40 years track record across every aspect of the built environment from design and build through to total facilities management & business process outsourcing. From his engineering origins, Steve has led national and international teams to realise over £11 billion of new sales.