Energy used directly in the construction sector includes large volumes of diesel for machinery as well as electricity for powering buildings and tools, presenting many opportunities to save on energy.
The benefits of energy-efficient design and construction practices are varied. Poor quality design can ‘lock in’ excessive operational energy use and environmental impacts for years. High levels of waste contribute to poor embodied energy outcomes, as well as resulting in poor air quality and amenity for workers and nearby residents.
Efficient diesel machinery and vehicles
Because of diesel's superior combination of power density, performance and reliability, it’s the preferred fuel in the construction sector, powering more than 75% of all heavy construction equipment. Newer diesel machines offer efficiency gains over equipment older than 15 years, as well as much better emissions control technology.
Ensuring machinery is well maintained also greatly assists in reducing diesel use. For example, filters are low-cost items which can be regularly replaced to maximise efficiency. Connecting construction sites to the grid earlier can also help minimise diesel use by mitigating the need for powered generators.
Engine idling can be a significant operating cost. On average, equipment on construction sites are idle around 25% of the time. Trucks are idle up to 50% of the time. In addition to unnecessary fuel consumption, this increases maintenance needs.
Implementing effective project planning and logistics can help reduce idling time. For example, the installation of automatic engine shutdown devices and offering fuel-efficiency training for drivers and operators.
Many diesel-powered construction machines can run on biodiesel blends of up to 20%. Biodiesel does not cost more than ordinary diesel but can substantially reduce CO2 emissions.
Newer forms of biodiesel are also emerging. ‘Renewable diesel’ fuels are near-identical in their chemical constitution to conventional diesel and therefore no blending is necessary. 100% renewable diesel can reduce lifecycle CO2 emissions by 50% or more.
About 40% of solid waste in Australia comes from construction and demolition. Finding ways to reduce, reuse and recycle construction waste will be essential to the sustainability of the industry.
Excavation waste can sometimes be re-used on site, such as being pressed into concrete masonry blocks. This reduces both landfill waste and construction truck traffic. Non-recyclable construction waste might be used in waste-to-energy processes, like powering kilns or producing liquid fuels.
The Australian Government’s National Waste Policy provides a framework for collective action by businesses, governments, communities and individuals to reduce waste and better manage material flows.
Onsite cabins represent one of the biggest opportunities to cut energy costs. With better shading, insulation, lighting and appliances, accommodation energy use can be cut by half. Onsite solar PV can then be used to meet or offset the remaining energy demand. The use of onsite diesel-powered generators should be minimised to reduce carbon emissions and local health and amenity impacts.
Design and material selection
Careful consideration in design, specification and planning can help avoid energy and environmental impacts.
Carbon-intensive materials like cement, concrete, plasterboard, limestone, brick and ceramics are responsible for around 40% of embodied emissions from construction. Combining measures such as using concrete made from a high percentage of recycled waste, low carbon cement, and good structural design, can significantly reduce embodied energy use. Selecting materials and components that can be easily recycled is also a good way to reduce energy-related impacts.
Quality construction lasts longer, reducing the need for energy in renovation or replacement works.
Issues with apartment construction quality have led the NSW Government to develop legislation that imposes a statutory duty of care on those who carry out construction work to the owner of the land.
Quality construction also avoids locking in excessive operational energy use, for example by minimising ‘downstream’ HVAC needs by ensuring air tightness in new buildings. Adherence to Greenstar and Passive House efficiency standards for airtightness are becoming more widespread in the construction sector.
Prefabricating components for a construction project can offer substantial energy cost savings. Offsite construction typically takes place in specialised, semi-automated environments optimised for waste minimisation and productivity.
Consistency of the offsite process can also lead to better quality construction which helps reduce downstream energy use and emissions.
Contracting and procurement
Construction projects typically require sub-contracting service providers and product suppliers. Requiring sub-contractors to meet minimum guidelines enables construction companies to reduce energy and environmental impacts in the supply chain.
Similarly, sub-contractors are likely to benefit commercially by demonstrating good energy and environmental management practices to potential employers.
Building information modelling (BIM)
BIM is an intelligent 3D model-based process that gives construction professionals the tools to efficiently design, construct and manage buildings and infrastructure. BIM allows greater productivity and energy efficiency during the design and construction phases and greater control during the operations phase.
Detailed 3D models can be easily shared, allowing engineers, contractors and suppliers to integrate their expertise before any money is spent on supplies. This helps ensure the best materials and methods are used during construction. BIM can also inform automation and robotic strategies, drastically speeding up construction times.
Design for reuse and deconstruction
The traditional approach to construction is to process from virgin materials with assumed disposal at end of life. Design for re-use and deconstruction acknowledges the need for a longer term approach, emphasising future re-purposing. This is achieved by designing for adaptability in use and layout, and ease of reconfiguration.
An example of re-use thinking in steel construction is using bolted connections instead of welded joints, which allows for easy dismantling. Use of standard components, fasteners and spacing allows for easy re-use in new constructions.
Cross laminated timber
The market for cross laminated timber (CLT) is growing quickly in Australia. CLT is made by adhering timber (usually hardwoods) together into heavy duty construction elements including multi-story framing and load-bearing walls.
CLT can replace concrete in many building types, even high-rise constructions over 10 storeys tall. CLT effectively sequesters carbon for the life of the timber, making it an excellent option for achieving net emissions reductions. Like concrete, it also provides substantial thermal mass which supports building comfort and energy-efficient HVAC.
To read more on timber and CLT in construction, see the Green Building Council Australia website.
Low carbon steel solutions
Steel is an essential material in many construction projects, but its production is extremely energy-intensive. Reducing the need for steel, or producing it more sustainably, is beneficial in lowering emissions.
Monash University has been involved in the development of a high-grade lightweight steel which can reduce embodied energy demand by greatly lowering the quantity of steel required for a given application. In the future, renewable hydrogen is likely to play a bigger role in the production of steel. The viability of using hydrogen in steel production was successfully demonstrated in Germany in 2019.
Hybrid and automated machinery
Hybrid powertrains are increasingly used in excavators, bulldozers, loaders and trucks. Combining the latest energy-efficient diesel engines with hybrid technology can deliver large fuel cost-savings.
Newer hybrid-powered machines feature autonomous technologies. The latest GPS and advanced radar technology optimise operations for improved productivity, safety and fuel use.
Robotics and 3D printing
Robotics is playing an increasing role in the construction sector, both onsite and in component production facilities. 3D printing is expected to revolutionise the industry by enabling components and even whole buildings to be constructed from materials sourced from the local area.
The Wasp Project in Italy has built and demonstrated a 3D printer that can produce a basic building structure from water, soil and vegetable fibre. The printer, which is 12 metres tall, runs on solar power.
Internet of Things (IoT)
IoT refers to systems of interconnected devices with unique identifiers, enabling secure connection and data exchange. IoT platforms coordinate information from a range of sources through a common language, allowing them to co-operate with each other.
Volvo Construction Equipment is connecting all of its construction equipment and funnelling the data to an offboard solution. The focus is on avoiding unplanned downtime for machines, also known as predictive maintenance. Through IoT the company monitors its equipment on a real-time basis and repairs a machine before the failure happens. To find out more, see the video case study on the internet of business website.
An increasing number of large companies are providing computer-simulation training to take advantage of a machine’s features for increased productivity and efficiency. Volvo Construction Equipment has been using virtual reality software to train its operators since 2011. To read more, see the ptc website.
Building and construction legislation in Australia Australian Government
Your Home Australian Government
Plain English Guide to Sustainable Construction (PDF 3.59MB) Construction Excellence (UK)
Shaping the future of construction (PDF 4.25MB) World Economic Forum