DECARBONISATION
This has become a commonly used word when talking about how to stop climate change. It essentially refers to the measures an organisation and/or industry needs to take to reduce their carbon footprint – mainly its emission of greenhouse gases.
In terms of construction, this relates to both the creation of new buildings as well as the retrofitting of existing buildings, some of which can be old and inefficient. Of the two, decarbonising existing buildings can be more of a challenge, but it’s incredibly important in helping us to meet the UK’s 2050 net-zero target as most of the buildings that will be around in 2050 already exist.
CARBON NEUTRAL
A great way to think of carbon neutral is that it’s a key milestone that you should hit on the way to achieving the end goal, which is net-zero carbon.
The principal behind being carbon neutral is that any carbon emissions produced are being balanced out by funding an equivalent amount of carbon savings elsewhere in the world through carbon offsetting. A carbon neutral company, product or building may not necessarily be low carbon, but a sustainable organisation will try to reduce its emissions before offsetting and will only use high-quality, verified credits.
CARBON OFFSETTING
Carbon offsetting is the practice of compensating for the carbon emissions you produce by purchasing measurable, verified credits. One carbon credit is equal to one tonne of carbon dioxide being reduced, avoided or removed from the atmosphere from certified projects.
Examples of projects could include tree planting or building a wind farm. A credible offsetting scheme will provide certified credits that can only be used once, and they will result in carbon reduction that is additional to what would have happened anyway without the project.
The fact that carbon credits can only be used once is important to note. When it comes to a building’s operational carbon the carbon produced must be offset every year.
CIRCULAR ECONOMY
A traditional, linear economy has a wasteful process of “take, make, use, dispose of”. A circular economy maximises usage to its fullest by designing out waste, designing in adaptability and keeping products and materials in use for as long as possible.
In construction this could be how concrete is reused. When an old building is demolished, often the concrete can be crushed and reused in a new building. Equally, it might be worth thinking about how you can apply this to entire buildings. There are alternatives to knocking down a building and building a new one, such as medium and major refurbishments.
Taking a circular economy approach will help to reduce embodied carbon.
EMBODIED CARBON
Embodied carbon is the greenhouse gas emissions (often simplified to ‘carbon’) generated in the lifecycle of a building, exluding operational carbon emissions.
It includes emissions that are related to the extraction of all raw materials, the manufacture and processing of all products or systems required in a building, transportation of those to site, assembly on site, and any maintenance or replacement activities required during the lifetime of those products or systems.
It also includes end of life processes, such as deconstruction and eventual disposal or reuse/recycling.
A pilot for a new, UK Net Zero Building Standard (the Standard) launched in 2024. The Standard will provide a consistent approach to verifying buildings as net-zero (for operational and embodied carbon) between 2025-2050. Find out more about the pilot Standard here.
NET-ZERO CARBON
A truly net-zero building will be net zero for both operational and embodied carbon.
In 2024, a pilot for a new, UK Net Zero Building Standard (the Standard) launched, which will apply to both new builds and retrofits. The Standard is the first-cross industry initiative that aligns to a 1.5°C climate trajectory and science-based targets. When finalised, it will provide a consistent approach to verifying buildings as net-zero (operational and embodied) between 2025-2050.
Find out more about the pilot Standard here.
OPERATIONAL CARBON
Operational carbon relates to the carbon emitted in the day-to-day running of a building, including heating, cooling, lighting, lifts, electrical equipment and more.
If a building is inefficient (due to poor thermal performance or inefficient building services) and/or doesn’t use renewable energy sources, it can result in high levels of operational carbon being emitted. When looking to decarbonise an existing building or create a new net-zero building, reducing operational energy and carbon emissions is critical.
A pilot for a new, UK Net Zero Building Standard (the Standard) launched in 2024. The Standard will provide a consistent approach to verifying buildings as net-zero (for operational and embodied carbon) between 2025-2050. Find out more about the pilot Standard here.
SCIENCE-BASED TARGETS
The Intergovernmental Panel on Climate Change (or IPCC for short) has calculated that global warming must not exceed 1.5 degrees centigrade above pre-industrial levels if we are going to avoid the most catastrophic impacts of climate change.
Experts have used computer modelling to calculate the overall reduction in greenhouse gas emissions that will be needed to ensure global warming doesn’t exceed this threshold. Science-based targets are how this modelling distills down to individual organisations.
These targets tell an individual organisation by how much and how quickly they need to reduce their own emissions so we can collectively meet our goal. Organisations whose carbon reduction plans are in line with science based targets can also have their targets validated.
UNREGULATED AND REGULATED ENERGY SOURCES
The energy used by a building when it’s in operation is split into unregulated sources and regulated sources.
Regulated usage come from the things that keep a building running such as heating and cooling systems, hot water and lighting. These energy uses are ‘regulated’ by Building Regulations and are typically used to measure a building’s energy efficiency through things such as Energy Performance Certificates (EPC) ratings.
Unregulated energy uses include additional things in a building like appliances, IT equipment, lab equipment, lifts and catering facilities. These uses aren’t controlled in the same way by Building Regulations, which means they can vary a lot from one building to another.
When you’re designing a building, both categories should be treated in the same way from a usage and cost perspective. Initially, the goal is to minimise the amount of energy being used. Once this has been achieved, enough renewable energy sources should be included to meet the energy needs of your building.