Technology
Today, fossil energy sources are mainly used on construction sites in Norway. In recent years, this has received increased attention due to a desire to reduce greenhouse gas emissions and local air pollution. SINTEF's report on emission-free construction sites divided fossil-free and emission-free energy carriers for working machines into five categories:

• Working machines powered on biofuels: Using biofuels in work machines is one way to bring down emissions. This option is not emissions-free, but fossil-free. Biofuels come in several varieties; biodiesel, bioethanol, biogas. According to the industry, the vast majority of working machinery (trucks, dump trucks, excavators, wheel loaders) can be run on liquid biodiesel (HVO).
• Hybrid working machines: Hybrid working machines have a diesel and electric hybrid solution. Such a hybrid machine may, for example, have a diesel engine that produces power for propulsion and drives the hydraulics. It can also have an electric motor for oscillation that also recovers energy from braking.
• Electric working machines (Wired): These work machines are wired to power supply and will mainly stand in a fixed location or move within a limited range. However, uncertainty arises on construction sites with cables since they have limited flexibility. There may also be limited capacity on the electricity grid where the challenges are greater with multiple machines running at the same time.
• Electric work machines (battery powered): Mobile electric work machines can move freely, and their use is thus limited only by the battery capacity. There is currently limited access to electric alternatives, but as demand for such alternatives grows, it is expected that the supply of emissions-free machines will increase over the next few years.
• Electric working machines with plug-in hydrogen: This hybrid solution is often referred to as range extender. The batteries can charge at night and during any breaks. During operation, the working machines draw the current from the batteries that can be replenished along the way by plugging in the hydrogen part. This technical solution is particularly suitable in larger machines where the electric battery capacity alone is not large enough to meet the energy demand.
  

Infrastructure
An important prerequisite for the large-scale phasing-in of fossil-free and emission-free technologies in the construction industry, as well as the transport sector, is to have a good infrastructure in place. The government has therefore drawn up a National Plan for Infrastructure with Alternative Fuels for the Transport Sector. Among other things, it involves charging infrastructure for electricity and filling stations for hydrogen and biogas until 2030.

Technologies such as electricity and hydrogen will challenge existing planning of building and construction sites. Energy consumption in different phases of a project and access to it must be planned in order to have better control and knowledge for the choice of measures. It also applies to a major electrification on the construction site with work machines, heating systems and charging stations that place demands on the capacity of the power supply. Any use of hydrogen and biogas/biodiesel as fuel for machinery must also be planned with regard to filling, safety, logistics and costs.