Mining companies are increasingly turning to alternative energy methods to keep fuel costs and greenhouse gas (GHG) emissions down at their sites and gain social licence, coinciding with a record year for renewable energy adoption and an increase in political will to fight climate change, delegates at the Energy and Mines World Congress heard in late November.

“What a great time for renewables for mines,” said Energy and Mines director Adrienne Baker in her opening address. “With 943 megawatts of wind and solar in terms of installed capacity now powering mines all over the world, we are getting closer to sustainable, low carbon energy for mines.”

The conference, held Nov. 21-22 in Toronto, highlighted successful renewable projects at mine sites and ones on their way to being built, took a look at the state of renewable energy adoption worldwide and focused on the key challenges to wide-scale application in the mining sector.

Renewables had a “record year” in 2015, said Heymi Bahar, renewable energy markets analyst at the International Energy Agency (IEA) in his presentation on global energy trends. Renewable energy capacities installed in 2015 surpassed installed fossil fuel capacity for the first time ever. “In the future [renewables] may surpass [coal in] generation as well,” Bahar said.

The IEA also updated its forecasts on investments in renewable energy by country, predicting that between 2015 and 2021, United States investments would surpass investments made by the European Union, which would be another first-ever, though Bahar conceded a coal-friendly Trump administration was not factored into the agency’s forecasts.

Trump was on the minds of presenters and delegates at the congress, held just two weeks after the U.S. election, with many wondering how his energy policies will affect renewable energy adoption and climate change mitigation initiatives like carbon pricing.

The energy projects highlighted during the conference indicated just how drastically attitudes have changed since the first Energy and Mines in 2013. While at that time there was skepticism expressed about whether solar and wind could be successfully applied at mine sites, this year presenters had far more ambitious goals.

Goldcorp’s Musselwhite mine in northern Ontario has eliminated the need for supplementary diesel generation over two years and reduced its grid usage, cutting GHG emissions by 20,000 tonnes of CO2 per year and making the mine more energy-efficient. According to Howard Boland, Musselwhite’s electrical coordinator, the site is now working toward electrifying its fleet to eliminate diesel use completely. At Avalon Advanced Materials’ Nechalacho rare earths project in the Northwest Territories, CEO Donald Bubar said the company has installed two 170-watt (W) solar modules that make up 20 per cent of the camp’s energy mix, making it likely the first exploration-stage miner to do so.

Iamgold CEO Stephen Letwin discussed the company’s plans for a 15-megawatt (MW) solar plant at its Essakane mine in Burkina Faso, to power the mine in conjunction with its 57-MW thermal plant. The site’s power needs have increased over the past four years as the majority of the soft rock has been mined and the proportion of hard rock is approaching 100 per cent. The solar plant would account for between eight and nine per cent of the site’s total generated power, and save six million litres of fuel a year.

While Iamgold constructed the 5-MW solar plant at its Rosebel mine in Suriname internally, taking on something three times that size has required working with a partner, who will build, own, operate and finance the project. Iamgold will buy the power from the plant for 15 years, with an opportunity to terminate the power purchase agreement (PPA) in nine. The plant will have an automated energy management system that will help maximize the solar usage, and the company is looking at batteries for energy storage. “The ability to store solar power will be a game changer,” Letwin said.

Storage technology was mentioned as a persistent challenge to wide-scale application of renewable energy at mine sites, with presenters noting it is still relatively new and in most cases prohibitively expensive. “There are ongoing concerns about how real the ‘falling costs’ are and when those will come,” said Cosmin Laslau, an analyst with Lux Research covering energy storage, distributed generation and solar. “It’s easy to still pay $1,000 or more per kilowatt hour (kWh) for storage.” Laslau said he expects battery projects to start making economic sense at $500/kWh, around 2020 and later.

Often brought up in previous years, another key barrier to miners embracing renewable energy has been the incompatibility between the expected life of a mine and the comparatively longer life of a wind or solar power plant. But that may be changing, with creative short-life PPAs.

Nick Boyle, CEO of renewable energy company Lightsource, highlighted the company’s new strategy for mining companies of signing PPAs with a term life as low as five years and developing solar plants that can be uprooted to another project after the company is finished with it. But the longer the PPA term, “the cheaper the price is going to be,” he added. “If you’re in a position to enter into a 25- to 30-year PPA, the prices you can get are incredible.”