With so much new built area predicted, improved construction materials, building techniques and monitoring technologies can minimise increases in carbon emissions due to energy requirements
As populations increase both in number and wealth, greater demand is placed on the construction sector. Growing populations, particularly in developing nations, tend to be on an upward path in terms of wealth, and as people have more money their expectations also rise.
This means more floor area has to be built for both residential and commercial use, and with that, energy demand also rises. Added to this trend are predictions around changing habitat usage due to the Covid-19 pandemic, where some think that as people work more often from home, their expectations for improved natural light, greater heating or cooling comfort and more space will rise.
The annual Energy Transition Outlook 2020 report produced by DNV GL writes that globally, the total floor area of residential and commercial buildings combined was 230,000 km2 in 2018. By 2050, it forecasts that residential floor area will rise by 52% and commercial floor area will more than double.
This increase is expected to place greater demand on energy resources, although improved energy-efficiency, better insulation and a shift towards more sustainable buildings will offset some of that growth. But increased demand for floor area will result in a growing carbon footprint for the construction industry.
Construction is responsible for 39% of the energy- and process-related global carbon emissions. Around 11% is associated with the pre-handover aspects of construction, with 28% of emissions emitted from a building once in use, for instance for cooling and heating indoor space, or heating water. About three-quarters of the energy associated with buildings is used by the residential sector.
Energy efficiency is becoming a far more important aspect of building design, because it can play a significant role in minimising the amount of additional energy required even when demand is rising. Whilst energy consumption is associated mainly with the aftermarket, once a building has been handed over, design, building practices and the materials used will help cap increases within the built environment.
Importantly for the GCC region, where summer temperatures are in the mid-40s °C, the report forecasts a huge rise in energy requirements to cool spaces. It says that globally, by 2050 the energy used to cool a space will almost triple, accounting for 12% of energy demand from 4.6% in 2018. The increase highlights the importance of designing energy efficient spaces to reduce cooling requirements, along with the role that monitoring technologies can play to ensure buildings are running at their optimum. Building materials – especially those with good insulation properties to keep cool air in – that are fit for harsh conditions, building orientation, shading and positioning of windows will all reduce the amount of cooling (or heating) that an internal space requires.
By improving these aspects energy demand for cooling an individual space can be reduced. Changing approaches to construction, such as modular building and 3D printing, will offer opportunities to invest in new construction materials, and recent work highlighted by RMIT University shows that novel approaches can be taken to improve materials in unexpected ways.
The net benefit of better insulation will be to reduce energy losses by 8%. However overall, greater demand for cooling due to increased floor area will outstrip savings in energy use gained from better insulation and efficiency, resulting in a net increase of almost 12 EJ/year by 2050, the report says. But as highlighted, improved construction techniques and materials will have a positive impact on those energy rises, preventing them from being even higher.
To an extent, this is shown with the change in energy use for heating spaces.
For space heating, final energy demand is forecast to fall significantly to 17 EJ/year in 2050, from 42 EJ/year in 2018. The reasons for this decline will be largely due to improved energy efficiency, better heating technologies and less power-hungry appliances in future, but again insulation will play an important role. DNV GL forecasts a 10% fall in energy used for space heating by 2050 due to better insulation. That figure will take into account all insulation, meaning better construction materials will also be an important factor. The report does warn though that despite the benefits and short payback period of implementing energy efficiency measures, “developers and retrofitters frequently fail to implement them”.
Increased residential floor space will also mean more associated services, such as schools, shops and hospitals, and better infrastructure, such as transport systems, will also be needed. Again, digital technologies such as BIM use during the planning, onsite technologies to monitor progress and those that improve efficiency after handover, such as digital twins, can all reduce final energy requirements and therefore the carbon footprint of the industry.
The DNV GL report highlights the future energy demand due to increased floor area. Whilst the construction sector cannot have an impact on all aspects of that demand, such as the efficiency of electrical appliances, it can play an indirect role in aspects such as the use of solar water heaters or LED internal lights, and a direct role in space cooling and heating, through the use of materials used and overall building design.
The full DNV GL report can be downloaded here.