Scientists from the Swiss Federal Laboratories for Materials Science and Technology and ETH Zurich have attempted to assess the potential contribution of recycling decommissioned fossil fuel infrastructure to green energy development. To that end, they analyzed the amount of metal contained in oil platforms, pipelines and coal-fired power plants to find out whether it could be used to build solar and wind farms. They found that, if recycled, these materials could meet a significant portion of clean energy transition needs.
The climate crisis necessitates a rapid renewable energy expansion, which means a sharp increase in demand for metals, especially steel and copper. However, steel and copper production remains a long, expensive and environmentally damaging process. For instance, it takes more than 16 years on average to bring a new field into production.
In this context, the researchers have proposed using the existing legacy infrastructure that will become obsolete as fossil fuels get phased out. They analyzed global databases of coal mines, oil-and-gas fields, pipelines and power plants, comparing them with data on the material intensity of these facilities. Analysis showed that these fossil fuel structures contain more than 6 billion tons of materials. While concrete constitutes the bulk of these materials, metals are the most valuable, totaling about 1.34 billion tons of steel and 10 million tons of copper. As a point of comparison, this is enough to fully meet the projected steel demand for the energy transition through 2050, as well as about a third of copper demand.
The scientists then assessed the full life cycle of steel and copper produced from primary raw materials, as well as extracted from recycled scrap. They simulated various scenarios through 2050, taking into account technological advances and energy balance changes. The results showed that recycling is more advantageous across 17 out of 20 environmental parameters. Specifically, greenhouse gas emissions could be cut by almost 2 billion tons of CO₂ equivalent, which is comparable to Russia’s annual carbon footprint.
The study’s economic conclusions are particularly illustrative. Metal production is accompanied by so-called external costs, namely, damage to human health and the environment that is usually not included in the price of the product, but is in fact paid for by society. For primary steel and copper, these costs are 4–9 times higher than the cost of the metal itself. Recycling can reduce these costs by 56–97% depending on the technology and scenario. This provides potential savings of $4–11.7 trillion by 2050.
The researchers also determined what could be built from this scrap metal. If steel from former oil rigs and pipes were used to construct wind turbines, it would build about 10 terawatts of onshore wind power, which is twice as much as the current projections. If this metal were used in solar power plants to replace aluminum in the structures, it would be possible to build 24–45 terawatts of solar panels.
However, the scientists note that this strategy could face resistance from owners of existing infrastructure, who are unwilling to decommission profitable facilities ahead of time. Nevertheless, the idea does not seem utopian: many facilities are already approaching the end of their service life, and coal-fired power generation is increasingly becoming less cost-effective than solar.
