TORONTO (miningweekly.com) – Renewable power is reliable, proven and continues to offer the mining industry an attractive means to obtain lower-cost energy at remote operations, Hatch director of renewable power Michel Carreau told an audience at a seminar hosted by the Canadian German Chamber of Industry and Commerce’s Competence Centre for Mining and Mineral Resources on Friday.

The mining and renewable energy sectors needed to continue engaging with each other to develop joint solutions, he added.

“This is a meeting of two worlds that, until quite recently, hadn’t worked together.”

RATE OF RETURN
Before a mining company selected a renewable component – whether wind, solar or another option – it needed to consider the economic viability and rate of return against the estimated mine life. The longer a mine was operational, the greater the benefits renewables ould deliver. 

“Levels are typically fixed. For example, 15c/ kW an hour would be a good bargain across 25 years,” Carreau said. “And while fuel costs are lower right now, remember this is just a moment in time; [the price will increase].”

The level of power penetration by a renewable component varied, with most providing mine sites with between 10% and 20% of their energy when in use. The goal of both the industries was to push this to a much higher level over the next five to ten years.

Renewables also delivered supply stability, as a wind farm or solar farm does not need consumable inputs such as diesel generator sets that required fuel to be transported, sometimes across vast distances. Further, renewables helped companies reduce their carbon emissions, which was popular with the wider public.

The growth in renewables’ competitive edge would spark greater uptake in the future, Carreau predicted. “When fuel costs go back up, renewables will be a key to lowering costs. And if your competitors are already thinking about [renewables], then you need to start thinking about it.”

NEXT STEPS
But even if the advantages of renewables were readily apparent, successful adoption depended on management being willing and keen participants.

Once a company was keen to progress, it needed to decide whether installation and operation would be under its own auspices or through a third-party provider of renewable technology under a power purchase agreement (PPA).

If a company decided on a PPA with a third party, it should still be prepared to share the risk. “If this was a $30-million investment and the mine was suddenly closed, where would [the investment] go?” Carreau asked, noting that it would have to be written off. 

Company employees needed to work hand-in-hand with those installing the renewable solution. This included those working or expected to work at the operation on a day-to-day basis. “Employees should be engaged in the study period [before installation],” he added. “Remember that each operation is different and there will be all kinds of effects that a renewable can have.”

On-site, hands-on training could be undertaken once the renewable component was placed and brought on steam. This usually lasted for around seven months as the operators became familiar with the technology and its position in the mine’s overall power generation.

WIND OF CHANGE
Carreau explored the successful installation of a 3 MW wind turbine at Glencore’s Raglan nickel mine, in the far north of Quebec. The turbine came on stream in August and was integrated into a 16 MW grid.

The region had one of the fastest wind speeds in Canada, averaging about 9.5 m/s. This compared with the 7.3 m/s average wind speed recorded at the Diavik diamond mine, in the Northwest Territories, which also operated a wind-diesel hybrid power facility.

Mine life at Raglan was estimated at 25 years, which made a renewable component viable. The programme started with wind monitoring in 2009, allowing for greater precision in the planning.

Several years of monitoring to secure still greater precision is usually unnecessary for a smaller-scale renewable option, Carreau noted. “If you already have a business case and know the returns are going to improve over time because of rising fuel costs, then you don’t need to spend something like another three years [doing this],” he said.

Although winter conditions had been tough at Raglan – currently hovering around -40˚ C or -60˚C if wind shear was included – performance had been good. Several icing events occurred across October and November but the turbine successfully de-iced itself.

Carreau reported one halt owing to too much icing, although this was followed with a quick restart. Raglan’s diesel generation system easily coped in the interim.

The mine’s turbine was designed to “de-rate” itself between -30˚ C and -40˚ C to protect the turbine blades in the cold, brittle atmosphere. It stopped itself at -40˚ C as a precaution. 

FUTURE IS BRIGHT
The next phase at Raglan involved the addition of energy-storage capacity and the use of excess wind energy to create further power opportunities. Part of the plan included the installation of a second and third turbine.

“But we want to test the storage component in the Raglan environment so that, when we start adding more wind turbines, the appropriate storage will be acquired,” Carreau noted.

More Raglan-style operations in the mining industry could be expected in the near future and the central driving force will remain the industry’s bid to reduce fuel costs, he predicted. “Because of this, renewable power will continue to play a major role in mining’s future.”

The lowering cost of renewables and storage, combined with increased efficiencies, would also be a catalyst and, beyond this, the industry could expect increases in the penetration of renewable power within mining grids beyond the 20% level.

“In the near future, a high-penetration system with energy storage – one that can lead to more than a 50% reduction in fuel consumption – will be there for us to reach out and grab,” Carreau highlighted.