4. Implementation

This chapter will first focus on reducing emissions from energy and transportation in phase A4 followed by A5E. This is achieved by utilising the Avoid, Shift, Improve hierarchical framework, where types of actions are listed in order of impact:

The focus will subsequently be on waste from phase A5W, guided by the 3R framework:

When it comes to the actual work on the construction site, there are numerous ways to reduce emissions from transport, minimise fossil fuel use, and minimise waste. The most straightforward and effective actions involve reducing energy consumption through improved transportation planning, reducing idling time, and minimising waste through better storage and planning. Many of the current barriers to emission-free construction can be overcome with careful planning, optimisation, and adaptation of current work practices. Planning ahead with key stakeholders is critical for the implementation of emission-free practices at construction sites, whether driven by one’s own ambition or external requirements such as tender conditions. In the earliest stages of construction planning, it is essential for contractors to create a plan that accounts for energy needs and power peaks, optimises transport logistics, and minimises waste.

Optimising the transport of materials, equipment, and waste disposal through planning and collaboration with key stakeholders can help reduce emissions. Source building materials from local suppliers and prioritise the use of locally available resources to minimise transportation distances. Avoid materials produced in remote locations as long-distance transport always requires considerable energy use. Limit the transportation of excavated mass by reusing and recycling materials as close to the site as possible. Engage with stakeholders, including suppliers and subcontractors, at an early stage in the project to plan for material availability and reduce transportation needs. Additionally, co-ordinate with other nearby construction projects to share resources and materials effectively.

When considering which modes of transport to use for the project’s transport needs, prioritise the use of available vehicles and transport modes that will minimise emissions. For example, use electric vehicles when available. If unavailable, use biofuel vehicles. Further discussion about low-carbon energy use can be found in Chapter 4.2. Early planning is essential for ensuring that the proper infrastructure exists for charging transport vehicles. If biofuels or hydrogen is used, ensure that an adequate supply will be available for the duration of the project. Consider the transport methods that other stakeholders (material hauliers, waste hauliers, others involved in construction site transport) are using, and engage in dialogue with them about using the lowest emission transportation modes available. When it comes to long-distance transportation, bear in mind that transportation by sea results in the least amount of emissions per unit of distance travelled, followed by rail.

Emissions reductions can also be achieved through driver training and the use of energy-efficient vehicles. Drivers can be trained to avoid idling and drive smoothly and efficiently, and to report when vehicles need maintenance. If fossil fuels are used, the most energy-efficient vehicles should be used. Optimising delivery routes and schedules can minimise travel distances and avoid traffic. This can also facilitate the use of smaller vehicles with a higher utilisation rate. Working with suppliers to optimise delivery times of equipment and materials can ensure that vehicles are loaded efficiently to reduce the number of trips to and from the construction site. There are many types of logistic software available that can help with transport optimisation.

Example: Material production and transport are the key to the most substantial emissions reductions. Lukutori Square was built using Finnish paving stones instead of stones imported from China, where the stones are usually sourced from. Had stones from China been used in the pilot project, its total emissions would have been more than three times higher. Although building using local materials requires more resources in terms of planning and contracting tenders, in the long run, carbon-neutral and sustainable construction is not more expensive, but actually helps to save money.

HNRY, ‘Emission-free construction site: green public procurement’. Accessed: Jul. 01, 2024. [Online]. Available: https://hnry.fi/en/emission-free-construction-site-green-public-procurement/

Although avoiding energy use on construction sites can be difficult, there are factors worth considering. To start with, it can be effective to look at all expected energy consumption on the site and identify ways to eliminate what is not strictly necessary and optimise energy use where possible. Construction sites vary in shape and size, so there are no ready-made solutions. Energy is typically used for machinery, on-site transport, heating, lighting, and various small tools and equipment.

The site layout should be planned and optimised to minimise energy use, especially considering earthworks and the transport of mass, where fossil fuels are often used. Energy for heating and drying can often be limited by preventing heat loss and not heating unused spaces. If possible, work should be planned to prevent the need to heat uninsulated spaces during the winter months.

If an electricity grid connection is not available and electricity is produced on site, special care should be taken to save electricity.

The use of fossil fuels on site is a major emitter of greenhouse gases. Diesel is traditionally used for heavy equipment and fossil-based gas is often used as a heat source. Electricity that is supplied to construction sites may also be produced from fossil fuels. Replacing this fossil fuel use with clean energy is one of the most important goals for EFCS.

Electricity supply to the site should be from renewable sources when possible. This depends on availability in each country or market area and is not within control of the construction industry.

Emission-free energy options for heating and drying include district heating, biofuels, and electricity. Using an emission-free district heating system is often the most efficient and economical choice. Biofuels are highly efficient when used as a heat source and can therefore be a better option for heating than electricity. Bio-methane is a clean burning gas that is widely available. Wood burners are commonly used in most of the Nordic countries. Although these are excellent heat sources, care must be taken to only use modern clean burning variants. Electricity can also be used for heating, especially in countries with ample supply at moderate prices. Heat pumps are also becoming popular where electricity is used for heating. Heat pumps can reduce the cost of heating with electricity considerably.

There are several energy options to replace fossil diesel in heavy machinery and trucks on site. Biofuels such as bio-methane, biodiesel, and HVO are commonly used and typically provide an 80% reduction in emissions compared to fossil diesel. These fuels can be used with current machine fleets and readily available equipment. The drawbacks are the poor efficiency of the combustion engines and local air pollution. It is also important to only select sustainably produced biofuels.

Battery electric machinery and heavy trucks are now becoming available. Although the upfront investment is high and availability is somewhat limited, the cost of operation is lower than comparable diesel equipment. On-site operations are completely emission-free, so there is no local air pollution and limited noise pollution. The main drawback is their short range, so the machines often need to be charged during the working day. Contractors should assess the availability of suitable machinery early on in the project and engage in discussions with subcontractors about accessing green energy equipment. When it comes to electric machinery, collaborate with power suppliers and grid operators before and during the project to understand potential constraints on the power supply, as the use of battery electric machinery can strain existing utility systems. Consider using battery containers to manage charging capacity issues. Combining battery-powered and cable-powered machinery can alleviate charging challenges. Designate an on-site charging and logistics co-ordinator to optimise charging schedules and manage any adaptation of procedures.

Hydrogen equipment is slowly coming to the market and hydrogen from renewable sources is available in some of the Nordic countries. Fuel cells convert hydrogen into electricity for use in machinery and vehicles. This is the optimal way of using hydrogen as there is a high level of efficiency and no emissions. Nevertheless, fuel cells are expensive and the production of large units is still limited. A fuel cell combined with a battery pack is an excellent choice for replacing diesel generators for on-site electricity production in cases where a grid connection is not available. Some larger construction machinery and trucks are available with hydrogen combustion engines. Although the burning of green hydrogen results in no carbon emissions, there are still some emissions of nitrogen oxide locally.

The availability of biofuels, hydrogen, or other clean energy fuels varies by location, underscoring the importance of early engagement with suppliers to secure a reliable, sustainable supply. Additionally, consider transport logistics and distances required for these fuels. The same goes for district heating and electricity connections. Arranging a district heating connection to the site can take considerable time and should be arranged as soon as possible, preferably as part of the project planning phase. When battery electric heavy equipment is used, a powerful grid connection is needed. This must be arranged at an early stage, preferably as part of the project planning process.

To optimise energy efficiency, consider the versatility of machines in fleet selection and task planning. Use the most efficient machinery and vehicles available. Efficient machinery usage can be achieved through worker training in optimal operation techniques. Look at all equipment that uses energy and assess the energy efficiency of the equipment itself and how it is used. One example of energy-efficient equipment is LED lighting, while efficiency in-use includes reducing the idling time of diesel-powered machinery. An overall improvement in efficiency requires trained personnel and the use of energy-saving standards.

It is essential to establish a comprehensive waste management plan before construction starts. A waste management plan assists in the identification and implementation of strategies to minimise the amount of waste generated.

The waste management plan should include instructions, routines, measures, and documentation methods. It should specify the amount of material that is planned to be reused and recycled, detail where the sorting containers should be placed and how many containers are needed, and whether these containers are required throughout the project or just for certain periods. The waste management plan should then be used to identify improvements that can reduce emissions from waste on site. Appointing someone to oversee and manage the waste management plan will help to ensure that waste is reduced, reused, or recycled properly.

Effective planning can help contractors better estimate material needs, optimise usage, and prevent excess waste, thereby reducing the overall emissions associated with waste production and disposal. When a material takeoff is conducted, the materials needed should be estimated as precisely as possible to avoid excess. The sizes to be purchased should also be considered to minimise off-cuts. Proper storage of materials and the optimisation of delivery times can reduce waste from product damage. Software such as BIM or other programs can be used to organise the storage of building materials and waste on site.

Although the reuse of building materials hinges on the designer, there are steps that contractors can take after the design is finalised. Reusing as much mass as possible is ideal, not only to reduce energy consumption from transportation as mentioned above, but also to minimise resource use and unnecessary landfill. One way is to reuse crushed concrete, bricks, or other aggregates for backfilling or non-critical applications. Additionally, when a large amount of excavated material needs to be removed, it is advisable to consider using it on site (such as in landscape designs in consultation with a landscape architect) or at nearby construction sites.

The waste management plan should look at opportunities for reusing existing materials on site. This applies to excavated materials and structures that will be deconstructed. Workers should be trained in deconstruction for the purpose of reuse and to prevent damage to reusable building materials.

It is essential to collaborate with waste management companies to ensure the recycling of waste materials. Maintaining ongoing dialogue with waste management companies throughout the construction project in order to communicate the goals of waste reduction and recycling of materials will help to optimise this process and inform waste management companies about the needs of EFCS. Dialogue should also be maintained with workers on site, who should not only be trained to use the waste sorting system, but also be informed about work practices that reduce waste generation.