The Rocky Mountain Institute, an organization focused on promoting profitable innovations for energy and resource efficiency, just published a report outlining what its researchers consider to be a feasible path toward sustainable mining.
The document, authored by Paolo Natali and Kevin Haley, reveals how extractive activities don’t necessarily have to be carbon-intensive, regardless of how high the energy demand of mining sites is. According to the International Energy Agency, the energy used by the mining industry represents 1.25 per cent of the world’s total energy consumption, which was 110,000 TWh in 2014 (or 375 quadrillion Btu).
“On-site renewable energy solutions for mining installations are becoming increasingly attractive to serve a significant portion of electricity load,” Natali and Haley write. “Approximately 32 per cent of the energy consumed at a typical mine is in the form of electricity, which can either be generated on site or supplied through a grid connection. The remainder of the energy consumption is fossil fuel based, primarily in mobile equipment with diesel engines (drills, shovels, trucks, etc.).”
On-site renewable energy solutions for mining installations are becoming increasingly attractive to serve a significant portion of electricity load.
In industrialized countries, many mines are connected to an electricity grid but that’s not the case in developing countries. In both contexts, however, energy needs have to be factored in either in terms of making use of the existing infrastructure without overloading it or having to build new plants.
A third way to approach this situation while reducing costs, the RMI report states, is by building a new off-grid facility with solar energy. “The key to unlocking viable low-carbon energy systems for mines has largely been the dramatic reduction in cost for renewable energy technologies and, to a lesser extent, battery and storage systems. Since 2009, the global levelized cost of energy (LCOE) for onshore wind has dropped by 66 per cent, and global solar LCOE has dropped by 85 per cent.”
According to the study, even if battery storage (which addresses issues with intermittency and night time load) is not available, a mine functioning with solar energy during the day and switching to fossil fuels in the evening would still reduce its energy costs and carbon footprint. “Additionally, renewables bring benefits in terms of reduced risk exposure to the global oil market and diesel supply chain.”
The authors provide more details as to how wind and solar have become cost-competitive when compared to fossil fuel-generated electricity. For example, “mining operators can lock in prices, either via on-site generation or long-term power purchase agreements (PPAs), at costs competitive with fossil fuel generation for as long as 25 years. The hedge against fuel cost volatility may be reason enough alone to consider renewables from an economic perspective.”
If they decide to build on-site generation plants, miners would see additional benefits to those of the reduction in their electricity bill and emissions. They would also gain social license.
“By serving a dual purpose to meet the needs of the mine and surrounding communities, renewable energy at mining sites can generate additional positive benefits in terms of social responsibility and community investment. This is, of course, in addition to the economic and environmental benefits of on-site renewable energy generation: providing the mine cheaper and cleaner forms of generation and using the local grid as a balancing tool that can offtake excess renewable generation and provide backup dispatchable generation at times of high load,” the RMI report concludes.