Green energy future begins in the mines
Renewable energy to power mines delivering green metals Metal Tech News Weekly Edition – January 1, 2020
Last updated 2/25/2022 at 11:33am
From the enormous equipment that dig up and haul ore to processing facilities that extract the sought-after metals, mines use a lot of energy. Over the past century, the largest share of this energy has come from fossil fuels. In recent years, however, an increasing amount of mine power is coming from renewable sources such as wind and solar.
Many mines are in remote locations that are beyond the reach of electrical grids, making them ideal for considering renewable sources of energy – if, that is, there is enough wind, sun or water to make the endeavor worthwhile. Mining companies, however, have been slow to adopt renewable energy due to the costs associated with establishing the wind, solar and battery storage needed to supply a steady power supply to mines.
This trend is beginning to shift as renewable energy costs fall. This is especially true for global mining companies with long-lived mines and a growing desire to reduce their carbon footprint.
And reducing the carbon footprint at mines producing the copper, aluminum, molybdenum, rare earths and dozens of other metals needed to establish the global shift to renewable energy has a multiplying effect. This is not lost on BHP Group, the largest mining company on Earth.
"Population growth and higher living standards combined with greater electrification are expected to push up demand for copper," said Daniel Malchuk, president, BHP Minerals Americas. "This means that copper in products such as electric cars and renewable energy infrastructure, which are vital to the world's sustainable growth, must be produced to the highest environmental aspirations."
U.S. copper mine goes green
Rio Tinto, the world's second largest mining company, has also put in place a major initiative to lower its carbon footprint by powering its mines with renewable energy.
"At Rio Tinto, our purpose is to produce materials essential to human progress. As such, we want to be part of the solution to help address the climate change challenge," said Rio Tinto CEO Jean-Sébastian Jacques. "Our aim is to make sure our business, and those in our supply chain, continue to deliver economic and social benefits in the short, medium and long term, as we assist in the transition to a low-carbon future."
The company is taking a significant step toward this goal by transitioning its world-famous Kennecott copper mine in Utah to renewable electricity.
In May, Rio Tinto announced that it is permanently shutting down its coal-fired power plant at Kennecott and is purchasing 1.5 million megawatt- (1.5 terawatt) hours of renewable energy certificates supplied by Rocky Mountain Power, primarily sourced from its Utah allocated portfolio including wind power from Wyoming.
These certificates, also known as green energy certificates, confirms that the power being acquired is from renewable energy sources. Sometimes this energy is generated within the immediate grid, but it can also be purchased from other sources and traded between utilities. This helps bolster demand for green energy providers, even if the buyers are outside of their immediate area.
The new energy structure at Kennecott is expected to reduce carbon dioxide (CO2) emissions associated with the copper mine by more than one million metric tons per year.
"This move will significantly reduce emissions associated with our operations in Kennecott and allow us to offer customers copper, gold and silver with a reduced carbon footprint," said Jacques.
In December, Rio Tinto announced that it is investing US$1.5 billion to extend operations at Kennecott to 2032. This means that the Utah operation will be a significant source of low-carbon copper that is needed to establish green energy infrastructure for at least another decade.
"Kennecott is uniquely positioned to meet strong demand in the United States and delivers almost 20 percent of the country's copper production," the Rio Tinto CEO said.
Renewable Chile copper mines
Not to be outdone, BHP is plugging its copper mines in Chile into green energy sources.
In October, BHP announced four new renewable power agreements to meet current and future power demand for its Escondida and Spence copper operations in Chile.
"These new renewable energy contracts will increase flexibility for our power portfolio and will ensure security of supply for our operations, while also reducing costs and displacing CO2 emissions," said Daniel Malchuk, president, BHP Minerals Americas.
BHP negotiated contracts to acquire 6 terrawatt- (6 million megawatts) hours per year of renewable electricity per year from Chile utilities. This will effectively displace 3 million metric tons of CO2 per year compared to the fossil fuel-based contracts they are replacing. By way of comparison, this is roughly the annual CO2 emissions of around 700,000 combustion engine cars.
Not only will the new power supply reduce BHP's carbon footprint, it is expected to lower the global miner's power costs at the Escondida and Spence mines by 20 percent.
This is expected to result in overall lower power costs, even taking in consideration that BHP wrote off US$780 million related to the cancellation of the existing coal contracts.
This creates a win-win situation for BHP.
"Good business considers the financial and social value in making decisions in the long-term interests of shareholders," said Malchuk.
Sun powered robot mine
It is not just the world's mega-miners that are turning to renewable energy. In December, Resolute Mining Ltd. announced that it is having a new solar hybrid modular power station developed for its Syama gold mine in Africa.
The renewable energy generator, which is being built by Aggreko plc, will combine battery, thermal and solar generation technologies into one integrated power solution.
Resolute said this hybrid plant will result in fuel savings, optimized plant operation, maintenance efficiencies and reduced emissions at the company's already cutting-edge gold mine.
Under the agreement, Resolute will pay Aggreko US15 cents per kilowatt-hour (kw/h) of sun powered electricity, a significant saving from the roughly US25 cents per kw/h the gold miner is currently paying based on diesel prices.
In addition to approximately 40 percent electrical costs savings, the new power supply is estimated to reduce the mine's CO2 emissions by 20 percent.
Such cutting-edge solutions are a good fit for Syama, which holds the distinction of being the world's first fully automated underground gold mine.
More information on the automation at Syama can be found at Robotic mines of the future are here in Metal Tech News.
"We can now look forward to significantly lower energy costs ... as we focus on maximizing the efficiencies of our new automated underground mine," said Resolute Mining CEO John Welborn.
These lower energy costs and efficiencies could be extended if the underground equipment ran on electricity instead of petroleum. Unfortunately, a fully electric underground mining fleet is not yet available.
"I would be delighted if we could electrify all of our equipment underground but the technology is not there yet," said Welborn.
There is no doubt, however, that electric powered mining equipment is right around the corner. So, the metals needed for Earth's renewable energy future are likely to be mined one day by robots that take turns charging their batteries from sun- or wind-generated electricity.