The mining industry in North America is big business, employing 615,000 in the United States and close to 400,000 in Canada. The metals and mining industry had total revenues of $172.5 billion in 2020. And mining activities require substantial power to operate in the most productive manner.
For those mining operations in remote sites, off-the-grid power systems that are both efficient and secure are essential, particularly for operations without easy access to a power grid.
Other power systems will need to be utilized on-site such as diesel-fueled power generators serving as a local micro-grid for both prime and standby power. These diesel generators must also prove themselves effective and reliable in all prevailing conditions, whether high altitudes or extremes in temperature.
Comparing underground and open pit mines, underground mines use considerably more power than the open pit kind. Underground mines require additional power for shafts, extractor fans, and dewatering pumps, for example. They will most likely require air conditioning and sites in colder climates may require some heating.
Natural gas-fueled generators are a reliable source of power if remote mines happen to be near a gas pipeline that can provide a tapped-in resource. These generators can provide continuous or prime power supply and are much cheaper to run than the diesel-fueled ones. They’re also considerably more environmentally friendly, with increased fuel efficiency, and have 34 percent lower greenhouse gas emissions.
As long as gas-fueled generators are well maintained they can function for longer periods, and some can run on a mixed hydrogen and natural gas blend. Natural gas generators are expected to see considerable growth in the next decade due to their much lower overall cost.
Parallel generating systems
Often remote mining site projects will require, in addition to diesel-fueled generators, parallel generating systems, switchgear, hybrid power systems, combined heat and power plants (CHP), battery storage systems, and acoustic enclosures, for example.
‘Parallel generating systems’ refers to the use of multiple power sources such as generators which synchronize the generator output for a short period prior to the transition to utility power. A closed transition is utilized to transfer loads with zero interruption of power.
This paralleling of multiple sources is good in that it increases reliability through increased redundancy. Redundancy proves more reliable than a single generator when it comes to handling critical loads; it also helps eliminate focus failure points; brings flexibility to load management; eases maintenance; and enhances serviceability through a reduced likelihood of disruption.
Hybrid power systems
Also known as renewable microgrids, hybrid power systems are typically found in remote mining sites. The power is generated by solar photovoltaic (PV) systems or wind turbines.
As noted by global energy solutions provider BWSC, this system “serves as a cost-efficient fuel saver for the reciprocating engines. The reciprocating diesel or gas engines generate power to balance the supply and demand of power in the system and provide crucial inertia for ensuring grid stability. In cases where short-term demand peaks are frequent, energy storage systems can provide sufficient energy to meet the demand.”
BWSC’s site goes on to note, “The energy storage systems can also be used to displace additional fuel and related costs when storing hours of renewable power for when the sun is not shining or the wind not blowing.”
In addition, energy storage systems can provide power regulation support, and thereby minimize the need for running engines. In some cases, storage can also substitute investments in engine capacity.”
Mohammad Sedighy, Principal Consultant, Electrotechnologies at Canadian engineering firm Hatch, told International Mining that “past attempts to incorporate renewable energy at meaningful penetration levels at these remote sites have proved challenging. Renewable power used to be expensive, and many early projects weren’t able to compete with diesel power on cost. The continuity of supply was an issue due to weather dependency and the variability of the renewable power generation itself.”
He goes on to say that “This is quickly starting to change. Hybrid power is on the cusp of making major leaps, thanks to falling costs of renewable energy, the maturity of several forms of energy storage technologies, and the advancement of smart, real-time dynamic control systems. We can now better integrate renewable energy into remote power grids through the improved performance and control of microgrids, with optimal sizing and use of energy storage.”
Combined Heat and Power plants (CHP)
Also known as cogeneration, a CHP plant provides a self-generation solution. The CHP generates sustainable electricity and thermal energy at the same time. Sustainable because heat that would normally be lost in processing can be redirected for other purposes such as steam to generate electricity or for steam chillers for cooling, for example.
According to the Office of Energy Efficiency and Renewable Energy, “CHP is a suite of technologies that can use a variety of fuels to generate electricity or power at the point of use, allowing the heat that would normally be lost in the power generation process to be recovered to provide needed heating and/or cooling.”
The site further explains that “CHP technology can be deployed quickly, cost-effectively, and with few geographic limitations. CHP can use a variety of fuels, both fossil- and renewable-based.”
And according to an article in Science Direct, “The main advantage of CHP is the efficient gain from saving natural resources and reducing emissions into the atmosphere, because it produces both heat and electricity at the same time.”
Battery Energy Storage Systems (BESS)
Many mining groups want to cut their emissions and can do so by relying on energy storage systems that enable them to increase renewable power consumption. BESS is an energy storage system that can be incorporated into a mine’s microgrid. Such technology serves to level demand through the reduction of peak loading and by storing excess renewable energy generated at a mine site.
According to SAFT, a global battery and battery systems company “The BESS allows the microgrid to maximize the amount of renewable energy it uses by compensating sudden variations in the power output of solar panels and wind turbines. The system will provide ultra-fast reacting spinning reserves to help maintain grid stability, which reduces the need to have diesel generator sets running idle for this purpose.”
Mining plays an essential role in any economy and is vital for the wellbeing of any community. Mining companies are quite often leading employers in communities. Aside from the extraction process, mining affords many careers in production, management, and scientific roles which can include engineers, chemists, consultants and geologists, to name a few.
As new technologies become part of mining industry it’s important to realize that aside from supporting thousands of jobs, the mining industry is the foundation of our modern lives, a driving force in any economy.