Mining operations are embracing the opportunities created by new technology, from automation and electric vehicles to renewable energy, but what can traditional fossil fuel power generation contribute to this technology-led evolution of mining? Craig Wilkins, Director Prime Power at Cummins, explains how natural gas power is key to meeting the industry’s power needs in the coming decades.
Many mining operations take place in remote parts of the world where access to large electric utility feeds is either unavailable or requires significant investments in electrical transmission and distribution. These same sites may also have little or no access to pipeline gas, or experience a variation of natural gas supply. In addition, they are operating in the most extreme climates imaginable, faced with blistering heat, the wettest humidity and high altitudes.
Therefore, the need to secure a reliable prime and peaking power supply to keep production up and running 24/7 is paramount.
Cummins has responded to this challenge with a significant investment into the natural gas arena with the launch of its HSK78G gas-powered generator, a flexible prime power solution for heavy-industry installations in the most extreme environments. Its extreme engineering is designed to push the boundaries of performance and challenge the perceived limitations of natural gas generators for mining operations. It has barrier-breaking fuel flexibility, able to burn pipeline natural gas, flare gas and biogas, even the lowest BTU methane down to 40MN, and free fuel sources, with high efficiency and low emissions.
The investment on the HSK78G comes as the power market across the globe is changing. Technological advances in renewable energy and its application with batteries as part of modular power networks, tend to dominate the future of power generation. The concept is flexible, scalable and able to power entire cities as well as remote off-grid installations – such as mines. So why invest in traditional natural gas power?
Gas vs diesel
Miners continuously look for ways to lower their cost of production. One of the major sources of cost for an open-pit mine site is fuel. Some mines have access to an un-interruptible supply of natural gas that offers them a lower total cost when compared to diesel.
Although technological advancements in natural gas storage and filling have yet to yield an economical replacement to diesel engines in mobile mining equipment, prime power generator sets are quickly moving towards lean burn, natural gas technologies. Lean burn gas powered generator sets use twice as much air in the fuel/air mix than required for total burn, which lowers burn temperature and NOx output, ensuring compliance with emission regulations.
Due to increasing emissions limits being adopted for generator sets, diesel generators sometimes are limited in their use. Lean burn, natural gas generator sets typically have ten times lower NOx than diesel equivalents (250-500 mg/Nm3 for natural gas compared to 2,500-3,000 mg/Nm3 for diesel.) Also, lean burn particulate levels are almost zero, so meeting location specific emissions regulations can be far easier across a global perspective.
Power generation fuel flexibility
Technological advances in design, running in tandem with market change, will result in gensets that can use fuel efficiently in varying qualities. This innovation is demonstrated by our new HSK78G, which delivers high electrical efficiency of up to 44.2% (50 Hz) and 43.5% (60 Hz) on a range of pipeline natural gas down to 70 methane number (MN) without impacting power output and efficiency.
Ultimately this fuel flexibility empowers operators to derive clean power from what would otherwise be regarded as waste products, at worst emissions. The technology for smarter and cleaner power solutions is speeding up and adoption will continue to grow as more mines embrace its capital expenditure (capex) and operational expenditure (opex) advantages.
Engineered to extremes
A further challenge for the mining operation is the environment in which the generator set operates. As engines operate, they produce heat and tend to be more sensitive to the ambient temperature levels. A generator’s ambient capability is defined as the maximum temperature at which it can operate without experiencing a loss of efficiency and it is an essential factor for customers operating in such extreme environments.
Without an engine capable of meeting high ambient temperatures, customers risk having to derate their engine, which can lead to reduced power efficiency and shorter operational life from the generator or having to stop it altogether. The HSK78G has been designed to operate at the highest ambient temperatures in the most remote locations, all far from the closest grid, offering full power capability without derating at 50°C (122°F) and 500 m (1,640 ft).
Gas vs renewables
The focus of many customers is to achieve the optimum levelised cost of electricity (LCOE) given the availability of different technologies which are suitable for their application. This can range from 100% gas generation through to a balanced mix of renewable sources such as wind or solar, and complementary storage technologies that leverages the reliability of gas generation to ride through periods where renewables are limited by their cyclical nature. The technology mix utilised will drive the different capex and opex cost scenarios that will ultimately affect the LCOE.
Improvements in gas engine technology, such as in the new HSK78G engine from Cummins, have pushed maintenance and overhaul limits well beyond the traditional envelope, thereby lowering opex costs over time. Jointly, we will continue to see cost reductions in storage and battery technology as volumes increase. For the near future, however, miners will continue to look for mixed technology to balance their capex and opex trying to achieve the lowest LCOE for its sites.
Preparation for electrification
As much as 40% of an underground mine’s energy outlay is spent on powering ventilation systems to remove pollutants from tunnels. Reducing the use of fossil fuels underground could have significant cost benefits for underground mines. In addition, The International Council on Mining and Metals have set their vision to provide solutions for minimizing the impact of underground diesel exhaust by 2025. As more underground mining vehicles and equipment contemplate the potential benefits of electrification, Cummins will continuously invest in power systems that will be ready to support such power need and respond to any changes in the mining industry
The right technology choice
In the future most power systems will require a mix of technologies that are specifically suited to their environment, emissions zone and location. Natural gas power offers mining operators an efficient and proven and prime power solution. From Cummins perspective, a lot of investments are made in new gas engineering technology, which are demonstrated with the HSK78G gas series. Additional product investments are being made within the 500-1 MW space, which will be released later this year, offering a comprehensive gas product portfolio to meet all market requirements. Progressively stringent global emissions standards are also driving Cummins investment into a variety of technologies – natural gas, diesel, batteries and fuel cells, to ensure that customers have the right power for the right application.