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Sustainability in construction: goals and progress

With the UK government aiming for “net zero” carbon emissions by 2050, the construction industry has a key part to play.  Reducing the environmental impact of a building, not just during but after construction, requires consideration of materials and systems, plus a working knowledge of the research and support available.  The good news?  Getting ahead comes with an economic advantage, as demand for sustainable builds continues to grow. 

The UK government’s commitment
We drive cars, fly in aeroplanes, and burn fossil fuel to heat our buildings: humans have developed habits which have had a dramatic impact on the planet.  Fossil fuels release gases which have caused the greenhouse effect, resulting in the catastrophic effects of climate change – like the high temperatures, flooding, and fires that we’ve seen in recent years.

Along with many other countries, the UK government has ambitious plans to eliminate the use of fossil fuels – and become what it calls “net zero” – during the next 30 years.

“The science could not be clearer: by the middle of this century the world has to reduce emissions to as close to zero as possible, with the small amount of remaining emissions absorbed through natural carbon sinks like forests, and new technologies like carbon capture.”
~ Net Zero Strategy (October 2021.)

It’s a task which will impact our daily lives in every area, from our homes and offices to our cars and streets.  In fact, two of the biggest areas in which change is needed, according to the latest report, are Heat & Buildings and Domestic Travel.  The work in both areas will be largely done by the private sector, with some government funding.

Heating and powering buildings currently accounts for 40% of Britain’s total energy consumption, so it’s a key target area.  The new report outlines a number of measures designed to reduce emissions from heating systems in homes and other buildings.  This includes stopping sales of gas boilers, and providing grants of up to £5,000 per household (April 2022) for the installation of low-carbon heating (like electric heat pumps or possibly hydrogen boilers).  There will be an additional £1.2 billion available to improve heating in the public sector.

The government wants to make Britain’s energy resources fully decarbonised – and reliant on renewable supplies – by 2035.  And it’s not just a ‘green’ initiative; it could also prevent UK householders from suffering when gas prices rise:

“Recent volatile global gas prices have highlighted the need to double down on our efforts to reduce Britain’s reliance on fossil fuels and move away from gas boilers over the coming decade to protect consumers in long term.”
~ Kwasi Karteng, Business & Energy Secretary

But of course, the boiler won’t be the only thing to change in our new builds.  During the planning, procurement, and construction phases, every new build creates its own carbon emissions, and the UK government has plans to reduce those too.

You probably already know that in January 2021 the government announced rigorous new standards for new builds.  It has also said that the requirements for extensions will change to improve energy efficiency.  With laws changing as the government rushes to meet the ambitious 2050 target, the construction industry will come under more intense pressure.

What does the construction industry have to do?

“The built environment[…] currently contributes some 40% of the UK’s carbon emissions and it is estimated that the construction sector contributes up to 11% of global carbon emissions.”
~ Royal Academy of Engineering (Sept 2021)

The government is pressing forward with its aim for all new buildings to have zero carbon output.  The reduction targets are 68% by 2030 and 78% by 2035 (compared with 1990 levels).

To assess a building’s carbon footprint, we need two figures. The first is OC (operational carbon dioxide) – the emissions caused by heating, lighting, and air conditioning during the building’s lifetime.

But we must also include the embodied carbon dioxide (EC) – which refers to the carbon caused by the construction of the building; any carbon emissions which wouldn’t have occurred if the building didn’t exist.  This includes transportation and manufacture of materials as well as demolition at the end of the
building’s life.

What causes carbon emissions during construction?
In the construction industry, most equipment and machinery is still powered by fossil fuels.  And the manufacture of materials is an energy-hungry process too.  In 2019, the Guardian estimated that the cement industry produces 2.8 billion tonnes of carbon per year – that’s 4-8% of the whole world’s CO2.   In the UK, concrete producers have worked hard to reduce this figure, achieving an impressive 53% reduction in emissions.  At Leeds University, research has shown that reinforced concrete can have a lower carbon rating; the team suggests that reusing concrete from demolitions is another progressive approach.

Although some people argue that timber has a negative CO2 rating (as it absorbs carbon dioxide while it grows), the processing of timber is thought to create significant emissions.  According to the New Scientist, figures have suggested that logging could be the third or fourth worst industry for emissions in the world.

Even recycled steel has caused new carbon emissions during its manufacture.

As we move closer to net zero, research and training is required to ensure that the most sustainable choices are made.

Becoming “net zero” requires dramatic change – but it also offers economic advantage for early adopters.  There will be new equipment and methods for making concrete and steel, new technology used for new homes, and new, sustainable, energy sources.  Those who adopt, adapt and deliver will lead
the way.

Designing a low-impact building
We don’t yet have all the information required to build the ‘perfect’ construction.  But we can use the latest research to make informed decisions in every stage of the process.  Drawing on current knowledge, what might a low-impact building look like?

– It is not built on a site where the environment or wildlife will be negatively impacted.

– It makes use of digital technology during the design phase (check out the government’s Building Information Modelling Schemes) to reduce cost and time.  This can include collaborative meetings, digital modelling, and accessing information.

– It is designed to include low-impact or reused materials.  Research is very young in this area, but countries such as Norway lead the way in carbon capture and sustainable forestry.  Innovators in reusing materials (like incorporating recycled aggregate in concrete mixtures – as seen in the London Olympics 2012) will have a claim to fame this century.

– It is built following best practice in low-carbon procurement and building.  This might include electric machinery and digital collaborations.

– It is designed (where necessary) with sustainable drainage, permeable pavers, and flood-resistant measures.  Flooding and higher temperatures are
recognised symptoms of climate change, and our building practice must change to reflect this.

– It is designed to provide efficient heating, with measures (such as ventilation) to prevent overheating.  This is done on a case-by-case basis; every build is uniquely positioned and might have different renewable energy resources in the immediate environment.  (In Norway, the National Museum is powered by the Oslo Fjord.)

– It is designed to be capable of zero Operating Carbon; these features might include efficient insulation, a fossil-free boiler, and solar panels.

Read more about sustainable construction
If you want to learn more about low-impact buildings, there are many helpful resources online.  The government’s strategy (just published in October 2021) outlines its latest policies in every area, including buildings and heating.

For information more specific to the construction industry, Leeds University’s research into reinforced concrete shows that there is potential to improve the sustainability of this widely-used material.  Carbon Action is a group that publishes and collates informative reports on topics relevant to the construction industry.

And for inspiration, read about some of Norway’s success stories in this article from the Explorer: Greening the Construction Industry.

There will be huge benefits to those who are building sustainably during the next 30 years.  As public demand and governmental support grows, research will help us to identify best practice and become world leaders in low-carbon construction.


SUSTAINABLE CONSTRUCTION: INTERESTING RESOURCES

Net Zero Strategy: Build Back Greener (Oct 2021)
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1028157/net-zero-strategy.pdf

Decarbonising
https://www.raeng.org.uk/news/news-releases/2021/september/construction-sector-must-move-further-and-faster-t

Clean Heat initiative
https://www.gov.uk/government/news/plan-to-drive-down-the-cost-of-clean-heat

Concrete: the most destructive material on earth (2019)
https://www.theguardian.com/cities/2019/feb/25/concrete-the-most-destructive-material-on-earth

The Carbon Footprint of Reinforced Concrete – Phil Parnell
https://eprints.whiterose.ac.uk/78456/1/adcr25-0362.pdf

Emissions of the Forestry Industry
https://www.newscientist.com/article/2215913-logging-study-reveals-huge-hidden-emissions-of-the-forestry-industry/

Mechanical trees capture CO2 passively
https://www.theengineer.co.uk/mechanical-trees-co2-capture/

Carbon Action 2050
https://www.ciob.org/campaigns/carbon-action-2050

BIS UK Construction Strategy:
https://d7.ciob.org/sites/default/files/BIS%20UK%20Construction%20Strategy.pdf?_ga=2.195570220.1626088204.1635333481-411414406.1635333481

Recycling construction materials
https://www.nibusinessinfo.co.uk/content/construction-materials-can-be-recycled

Norway is Greening the Construction Industry
https://www.theexplorer.no/stories/architecture-and-construction/norway-is-greening-the-construction-industry/