Climate change, greenhouse gas emissions and carbon footprints have become worldwide issues affecting many communities. They require intervention to reverse the current trends. Construction is a significant contributor to the problem with 39% of global energy related emissions coming from this sector.
Fortunately, the statistics on construction and CO2 emissions are becoming more widely communicated. New strategies are being developed to improve the carbon emission performance in the construction industry. (Read Understanding Construction Emissions: What’s Causing Greenhouse Gases & How We Can Improve.)
Carbon emissions from the construction industry come from multiple sources. A major contributor is the burning of fuel in the vehicles and equipment used in construction. Energy is used to make construction materials, and this also contributes to the overall load of the industry.
Another way the construction industry can help is in the use of sustainable development practices.
Using Efficient Vehicles and Equipment
Construction sites are normally filled with diesel driven equipment and generators. This is due to the remote locations where access to grid power is not always available.
However, every diesel equipment like a heavy HDD rig or crane is constantly burning fuel and emitting CO2. There are a few practical ways to minimize the use of diesel on construction sites:
- Use the smallest size engine that can deliver the required power. Bigger engines use more fuel and some of this is wasted due to excess capacity.
- Use the latest and most efficient engines. When renting equipment for construction projects, you have the option to specify which type of engine you are willing to use on your site.
- Use grid power when available. While this is not carbon-free, it does reduce the fuel consumption on the construction site.
- Schedule work so that equipment runs at full capacity while on site. This eliminates wastage due to idle time.
Using Lower Embodied Carbon Materials
Every piece of material used on a construction project is manufactured somewhere. Energy has already been consumed and CO2 emitted before it even reaches the site. Researchers have developed a database known as the Inventory of Carbon and Energy (ICE) database.
It shows the embodied carbon of different materials — this means the carbon emissions generated during its manufacture.
Using this database, construction companies can compare the embodied carbon of the different material options at their disposal. It is useful for the decision-making process, which should include both financial and environmental priorities. Over 220 materials are available on the ICE database covering all the major categories of building materials.
It is interesting to note that cement production is a major energy user and therefore CO2 generator. Reducing the amount of cement used can have a significant impact on the carbon footprint of a construction project.
On the other hand, using lower embodied carbon alternatives reduces the carbon footprint. Pulverized fuel ash is one example of a cement alternative with lower embodied carbon.
An informative study compared the embodied energy of copper versus polypropylene piping. They note that the cost and performance of both products was quite similar, therefore the primary differentiator between the two would be their environmental performance.
The study concluded that copper piping had a far higher embodied energy than polypropylene piping.
Recycling and Repair
Recycling is an obvious method to reduce carbon emissions. New material has the full embodied carbon of the manufacturing process. However, the embodied carbon of recycled materials has already been accounted for in its first use. Every time we recycle material, we save on the energy that would have been consumed to manufacture new material.
Recycled plastic as a source of material for pipe manufacture is becoming more common. Experts report that pipes made using a combination of virgin and recycled high-density polyethylene (HDPE) perform at equal levels. Recycled plastics are especially attractive for gravity flow applications making them ideal for sewers.
As ageing sewer networks need to be replaced, piping made from recycled plastic offer an environmentally sustainable source of material. (Read Using Trenchless Technology to Replace City Lead Pipes.)
Trenchless rehabilitation is also a contributor to reduced energy consumption through repair instead of replacement. Trenchless methods such as sliplining extend the life of existing piping by sealing leaks. (Read An Overview of Sliplining.)
This extended life means a delayed purchase of new material and therefore a reduction in carbon emissions from manufacture.
There are a number of factors related to construction practices that can contribute to higher emissions impact. These include the design of buildings using energy efficient methods, thus reducing their ongoing energy costs to operate. There is also the ease of deconstruction and reuse.
Construction practices that make it difficult to demolish and reuse material have a negative impact on long term emissions from the industry.
New trenchless construction projects should take into account the expected lifespan of the installed piping. A shorter lifespan means more regular maintenance and earlier replacement, which has negative financial and emissions impacts.
Piping routes should take into account trenchless repair methods, making it easy for an efficient repair in future.
Removing waste from a construction site is costly and generates harmful emissions. Diesel trucks burn fuel for each load from the site to the disposal area. In addition, the embodied carbon of dumped material contributes to a poor emissions performance.
Waste minimization is therefore an important strategy for mitigating emission impact from construction. It is important to manage stock so that materials arrive when they are needed. A good materials management program ensures materials don’t lie around too long on the site, thus minimizing the opportunity for damage.
The construction industry is a major contributor to greenhouse gas emissions and the resulting influence on climate change. Fortunately, there are a number of ways to adopt better methods for reducing emissions.
Using efficient machines and vehicles, low embodied carbon materials, recycled materials and sustainable practices can make inroads into the emissions caused by construction activities.