Copper use in the energy transition contributes to energy savings, reductions in energy costs as well as reductions in greenhouse gas (GHG) emissions. But what about the costs, energy use and GHG emissions for producing the additional copper? In this article, we focus on the GHG balance. Similar conclusions could be drawn for the energy and cost balance.
When increasing the energy efficiency of cables, GHG savings can be directly attributed to conductors. In cables, copper is the active material producing these savings. Therefore, the resulting savings can be fully attributed to copper, and a GHG balance can be calculated when comparing with copper's environmental profile. In the example in the reference below, this leads to a GHG payback factor of 33. A correction could be calculated for the additional insulation material of the thicker cable, but this effect will be small. Such effort would be better spent to get a more accurate estimate of the duty cycle for that cable, since the use phase represents well over 95% of the GHG footprint.
When improving the energy efficiency in electrical machines such as motors and transformers, there are various design strategies to improve efficiency. Increasing the conductor cross section can be used in addition to using better steels or different designs. Typically, about 30% of energy savings and hence GHG reductions can be attributed to copper. This leads to payback factors in the range of 20 to 300.
Moving to other solutions such as renewables and emobility, these also use more copper in comparison to a fossil power plant of an Internal Combustion Engine (ICE) vehicle. However, these systems need many other materials besides copper. While copper remains the active conductor in the system, there is no agreed methodology to attribute GHG savings to the various materials and processes used. Still, it can be illustrative to calculate how long the system needs to operate to compensate for the emissions related to the additional copper production, in order to provide an indication whether there is enough time to earn back the GHG invested and generate a positive GHG balance. When performing such calculations, we find the following results:
- Renewables (wind or photovoltaics): GHG related to copper production are earned back in 1 - 2 weeks
- Battery Electric Vehicles (BEVs): it takes 2,300 km of driving a BEV compared to a ICE vehicle to earn back the copper's GHG emissions.
The above numbers are based on the Copper Environmental Profile that provides a GHG footprint for a global cathode, based on a mix of primary and secondary material sources as per the production practice in 2018. It doesn't take into account that copper in the above applications is highly recyclable and can start a second or subsequent life after its initial lifetime.
- For more details and references on the above numbers, check ECI publication Cu0279 - https://help.leonardo-energy.org/hc/en-us/articles/6572659727890
- For an example of an energy balance calculation, see How much energy & greenhouse gas emissions are saved when upsizing a cable?
- Copper Environmental Profile
Last update: September 22, 2022