19 minute read
Can – and should – mines go o the grid?
CAN (AND SHOULD)
MINES GO OFF THE GRID?
By Trevor Crighton
Renewable energy plants won’t allow mines to go completely offgrid just yet – but will allow them to make significant reductions in emissions and take substantial pressure off Eskom. “The increase of the generation licensing threshold from 1MW to 100MW is one of those rare ‘stroke of the pen’ reforms that unleashes enormous financial, economic and environmental value,” says Sedibelo
Platinum Mines chief environmental, social and governance (ESG) officer Lael
Bethlehem. “It’s an extraordinary reform that provides relief to Eskom and has a spin-off in terms of supporting South Africa’s growing green economy.” Norton Rose Fulbright head of energy
Matt Ash says mines can take advantage of the change in two ways – with embedded behind the meter generation or distributed generation. “In the case of the former, the generation site would be situated on land owned by the mine and near to the operation where it is required,” he says. “That’s easier than the latter, where the generation facility is located remotely from the mine.” Distributed generation with wheeling is a financial, not physical, transaction, with an independent power producer (IPP) being credited for the electrons injected into the network on its accounting system and the offtaker being entitled to take them off the network at the other end, with adjustments made to supply.
Ash says from a behind the meter point of view, the change in the threshold means that mines wanting to do so can simply get on with it. But there’s a challenge for those looking to operate a distributed model.
“The problem is that the Eskom network is physically incapable of having hundreds or thousands of IPPs feeding energy into it, without significant risk of network destabilisation – which could happen in a nanosecond and see the entire country in the dark for two to three weeks should the network fail.”
Another challenge in using renewable energy is intermittency of supply, so if the load were to suddenly disappear – or power unexpectedly become available – it would quickly destabilise the national grid.
“These distributed connections wouldn’t all be possible until there is a set of rules around balancing the grid that is agreed on by all players, also with penalty consequences for those who breach the rules,” says Ash. “That said, we’re doing a lot of work with mines that have a mix of embedded and distributed generation, coupled with some battery storage systems to deal with intermittency – they’re voting with their feet and moving forward with their plans.”
GOLD FIELDS’ HEAD START
Gold Fields is proceeding with building its own R715-million generation plant at South Deep, Johannesburg, which should be commissioned in the third quarter of this year.
“Our application for construction of a 40MW solar plant was approved by the National Energy Regulator of South Africa in February 2021. When the increase in embedded generation was announced, South Deep carried out a further optimisation study which revealed that upgrading the solar plant by an additional 10MW would unlock maximum value within the mine’s current ability to make use of additional power generated,” says Martin Preece, SA’s executive vice president of Gold Fields.
“Taking this into account, the change of scope will increase capacity from 40MW to 50MW and allow for future expansion to 60MW within the existing environmental authorisation.”
The plant will increase power generation from 94GWh per annum to 103GWh per annum – 24% of South Deep’s annual electricity consumption – and reduce its CO2
We have opted for a combination of wind and solar so each supplements the other. “ “ – Bethlehem
footprint by around 110 000 tonnes.
By covering South Deep’s baseload requirement, the plant will allow for shi ing pumping and other key activities – which were traditionally done at night – into the daytime window, with no surplus energy generated.
“Of course, solar energy can only be generated during daylight hours, and to further reduce our dependency on grid power, both alternative renewable sources of energy as well as storage solutions are being investigated.
“Given the unpredictable nature of renewable sources of energy, if we were to rely solely on renewables, we would need to install between two and three times our baseload requirements, which is why viable storage solutions are a critical part of the puzzle to solve,” says Preece.
“We are encouraged by the potential of wind as a source of renewable energy, as well as the advances with storage solutions, and will be pursuing these aggressively.”
Sedibelo’s Bethlehem says the size of the plants will depend on demand, and not many miners will need as much as 100MW of their own generation.
“We released a request for proposal for a 40MW plant that uses a combination of wind and solar generation, and in time hope to supplement that with battery storage when that becomes financially feasible,” she says.
“Renewable energy works well when the natural resource is available. We have opted for a combination of wind and solar so each supplements the other, but are aware that renewable energy alone cannot provide 100% of our 24-hour requirements. We think our plant will provide us with 55% to 60% of our 24-hour demand, with wind and solar working in tandem.”
DUAL BENEFITS
Norton Rose Fulbright head of mining Christina Pretorius says it’s important to remember the dual benefit of increased selfgeneration for mines. “Along with developing a more sustainable power supply, the inclusion of renewables will positively impact their environmental footprint,” she says.
“I’ve seen press reports that the mining industry is responsible for between 7% and 9% of global greenhouse gas emissions, and trying to reduce that footprint is a nobrainer. Increased environmental regulation and the need for their own ESG imperatives are driving them strongly towards selfgeneration, giving them a more stable supply as well as having a positive impact on the environment.”
Certain mines are using this to benefit the communities in which they operate, giving free equity stakes and creating jobs that will upli them and feed into ESG imperatives, says Pretorius. She believes mines will also look to partner with existing IPPs rather than reinventing the wheel.
“There are companies out there that have established thousands of renewable generation plants, and it makes sense to work with them, because they’re good at what they do. I don’t think it makes sense for a business as large as a mine to completely pivot and turn something that would facilitate their main business into their main business.
“Why would a mine turn into an energy generation facility developer? They can support, invest and commission renewable energy plants, but I certainly don’t see them becoming generators themselves,” she says. ■
DUAL BENEFITS
Increased self-generation for mines will: ■ Develop a more sustainable power supply. ■ Positively impact the environmental footprint.
Martin Preece.
Christina Pretorius.
Matt Ash.
Lael Bethlehem.
HOW COP26 AGREEMENTS
MAY AFFECT SA’S COAL MINING INDUSTRY
By Benjamin van der Veen
With the decision taken to “phase down” the use of coal by 2030, South Africa’s coal industry will certainly have to adapt to a new reality.
The United Nations Climate Change Conference (COP26), all a part of the UN Framework Convention on Climate Change (UNFCCC), took place in Glasgow, UK, in November last year.
Many had high hopes for COP26 to finally provide concrete answers and actionable plans, where nations would take accountability and come to an agreement to ensure the original Paris Agreement formed at the COP21 in 2015 was kept – or was at least on target to being fulfilled.
However, many green activists and nations were le with a bitter taste a er the conference. South Africa’s coal mining industry in particular may have a lot to say on some of the agreements delegates committed to fulfilling.
COP26’S AIMS AND AGREEMENTS
COP26 saw many debates, initiatives and speeches concerning how the UNFCCC should approach the goals set out in the Paris Agreement, and solutions to further decrease the e ects of global warming by phasing out the use of ine icient fossil fuels. Countries in attendance were asked to present their 2030 emission reduction targets aligned with reaching net-zero by 2050.
Nations will have to begin accelerating the phasing out of coal, install measures to prevent deforestation, invest in renewable energy and renewable energy research and development, and accelerate the switch to electric vehicles.
COP26 is the first time there has been a clear plan to reduce the use of coal.
The agreement – known as the Glasgow Agreement – was initially created around phasing out the production and use of coal entirely by 2030. However, a last-minute secret meeting that took place between the United States, Chinese and Indian governments saw the wording of the agreement changed to “phase down” (lower the total use) instead of “phase out”.
Developed nations pledged to significantly increase money to help developing countries deal with making the switch to clean and renewable energy and the adverse e ects of climate change. South Africa and other developing nations were happy to be told that the $100-billion in incentives promised during the 2009 COP event in Copenhagen would be fully paid out by 2025. Developing countries were also o ered the prospect of a trillion-dollar-a-year fund from 2025.
COAL MINING AND CONSUMPTION
To further understand all that happened at COP26 in securing a global net-zero future and South Africa’s coal mining industry, SA Mining spoke to Minnette Le Roux, a principal environmental specialist and head of the environmental department at NSDV.
“Severe impacts of global warming at 2°C have become clear, rather than the Paris limit of 1.5°C warming. Some major highlights of the COP26 are to keep the goal of 1.5°C warming alive by implementing greater actions and taking immediate steps to reduce global emissions.
“It is also the first COP where the decision was taken to explicitly target action against fossil fuels, calling for a ‘phase down’ of ‘unabated coal’ and ‘phase out’ of ‘ine icient’ fossil fuel subsidies.”
Le Roux further explains that for South Africa to reach the agreements and goals set out, SA’s coal mining sector would have to take certain steps. “The South African coal mining sector would need to adapt.
“This can be seen in the recent Mine Closure Strategy under public and stakeholder consultation. This strategy includes a drive for closure of mines to be at least carbon-neutral and for mines to implement carbon-negative plans via sequestrating or o setting.”
The South African coal mining sector would need to adapt. – Le Roux “ “
ALTERNATIVE ENERGY – A SOLUTION?
In 2019 South African coal mines produced 258.9 million metric tonnes of coal, equivalent to sales of R139.3-billion. During the same period, the coal mining industry employed 92 230 people, representing roughly 19% of the total employment within South Africa’s mining sector.
Therefore, the news of South Africa’s acquiescence to the Glasgow Agreement at COP26 has led to concern within the coal sector. >
“Renewable energy, combined with storage and smart grids, is a viable alternative. “ – Marsay
When asked about renewable energy alternatives as a possible solution to South Africa’s coal problem, Nicolas Marsay, an independent specialist in broad-based black economic empowerment, economic development and localisation, said: “Renewable energy, combined with storage and smart grids, is a viable alternative. However, South Africa can further explore utilising more e icient coal power generation technology while reclaiming existing coal waste dumps by using new extraction technologies.
“Whereas green hydrogen has gamechanging potential, significant research and development investment is required to bring pricing down to be economically viable. Thorium-based nuclear power is an excellent medium to a long-term alternative too.”
The use of carbon-neutral, more e icient coal power generation and rehabilitation planning seems to be the best short-term alternative for South Africa’s coal mining sector. However, the e ectiveness of specific renewable energy sources such as solar energy is entirely dependent on the geography of the power plant.
Renewable energy companies and mining companies alike will have to make sure that they research the correct locations for these renewable energy sources to be used to their maximum potential.
Coal mining companies Exxaro and Seriti Resources, which supply the state-owned power utility Eskom with over 80% of its annual coal supply, have already begun shutting down and transforming their closed mines and available properties into renewable energy farms.
Eskom, Exxaro and Seriti Resources all stated when signing the memorandum of understanding (MOU) between them that the pursuit of this project would create upskilling opportunities for local mine communities situated around their mining operations and additional employment opportunities. It would also allow South Africa to take a step towards a transition to a low-carbon future. The signing of the MOU is a massive step in the right direction concerning upskilling, retention, and the addition of labour within the coal sector.
The memorandum also puts South Africa in a better position to fulfil its goals in the Paris and Glasgow agreements and allows for a more e ortless switch to renewable energy. ■
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■ Secure global net-zero by midcentury and keep 1.5°C within reach. ■ Adapt to protect natural habitats and communities. ■ Mobilise finance. ■ Work together to deliver.
DIESEL FILTRATION
in the mining industry
By Jannie Botha
The last thing a mine needs is for production to be stymied by equipment failures caused by contaminated diesel. E ective fuel filtration solutions can prevent this.
The e ectiveness of a diesel engine depends largely on how good its fuel filtration system is, particularly as the results of poor filtration are far more problematic than black smoke from the exhaust and a lack of engine horsepower for the vehicle.
In a tough economy, rapidly escalating operating costs – not only regarding fuel, but also the expense related to unexpected equipment downtime – along with increasingly strict environmental legislation around greenhouse gas emissions have le organisations with large diesel fuel user bases facing very di icult challenges.
Organisations that operate fleets of small to large diesel-powered vehicles need to ensure optimum engine performance and reliability. Most especially, says Hydac Technology sales manager Jannie Botha, particulate and water contamination in diesel fuel must be controlled to acceptable, or within specification, limits.
FILTRATION CHALLENGES
“The mining industry operates a multitude of di erent types of equipment that require diesel that is properly filtered to ensure optimum operations. Whether we are talking plant equipment, mine vehicles of all sizes or simple generators, ‘dirty’ fuel is a menace to e ective use,” he says.
“Improperly filtered fuel a ects not only your consumption thereof, but also the quality of service obtained from the equipment, as well as its eventual length of life. It leads to an increase in equipment failure, and to more equipment standing idle for longer periods, which ultimately means your bottom line will feel the impact.
“On the other hand, e ective fuel filtration most certainly increases availability and reduces downtime, something that is absolutely critical in an industry that is extremely production-driven.”
Botha notes that all fuel contains some water in suspension, but because diesel is less refined, it holds more water than other fuels. vehicle, there is still a possibility of the fuel becoming more ‘watered down’, as in the standard operation of the engine a certain percentage of diesel used for injector cooling is returned in a heated state back to onboard diesel tanks, which obviously leads to additional condensation.”
He says additional water can find its way into the fuel from cross contamination, such as through diesel the . When fuel is stolen, the missing liquid is o en topped up with para in or water, he explains, causing trouble for the purchaser’s equipment in the end.
“In addition, the storage of diesel fuel also creates an environment that allows for more water contamination, as air containing water vapour gets into the tanks during the dispensing process, and this leads to more water molecules in the fuel as this condenses into water droplets inside the storage tank.
“Even once the fuel is on board the
MORE EFFICIENT FILTRATION
Besides the challenges this can create, including the costs related to vehicle repairs, a loss of productivity and less e icient fuel consumption, there are other costs for e.g. replacement storage tanks should these tanks rust, he says.
Moreover, he says, mining depends on energy, which is problematic in a country that frequently has to deal with load shedding. To overcome this, many mines use backup generators for power, and e icient filtration is also key here, because “dirty” diesel can lead to generator failure, leaving the mine bere of power during a blackout.
“Standard on-board fuel filters today are not really capable of handling high levels of diesel contamination. Therefore, to prevent premature plugging and frequent change-outs of these fuel filters, fuel cleanliness should be controlled throughout the entire fuel supply chain.
“To put this into perspective, newly delivered bulk diesel fuel typically has an ISO cleanliness level of ISO 22/20/18 to ISO 21/19/17, but today’s injection fuel systems require a fluid cleanliness level below ISO 14/11/9 – essentially the same level of cleanliness as aerospace fuel.”
He says Hydac Optimicron Diesel filter elements have been specially developed for
the filtration of diesel, and are characterised by very high contamination retention capacity, coupled with low pressure drop.
This has resulted in extended service life for these elements. Use of the most up-todate materials further guarantees excellent separation rates, even in a single pass, and this continues over the entire element life cycle while in operation, he says. The Hydac Optimicron two-stage diesel dewatering elements use materials specifically designed for coalescing and for separating water from diesel. These elements enable a secure e icient dewatering capability, even at greater quantities of water in diesel.
END-TO-END FILTRATION
“This helps the organisation achieve the lowest cost of ownership, while at the same time significantly improving production, because vehicle breakdowns are reduced. In addition, the equipment will have a longer lifespan,” he says.
“At Hydac, our product range actually includes something for every step of the process, from production to consumption. In other words, we can assist with key diesel filtration solutions from the refinery to the ship, and from the tanker to the storage tank on the mining site, and from there to the mobile bowser and into the actual plant equipment.”
He says Hydac can also help with “fuel polishing”, which helps to avoid the challenge created by fuel stored for longer periods. Mining sites buy a lot of fuel, which is o en stored for lengthy periods, and this can lead to issues with water condensation inside the tank. The fuel is polished by shi ing it from one tank to another, which enables it to undergo a filtration process.
“We also o er on-board filtration solutions that help to filter the fuel between the plant equipment’s fuel tank and the main engine filter.”
From a sustainability perspective this is also positive, as all equipment using these filters has lower levels of exhaust emissions, thanks to using cleaner fuel.
“Cleaner fuel also ensures your fuel injectors are able to last longer. Ultimately
ISO 22/20/18 to ISO 21/19/17
Typical cleanliness level of bulk diesel fuel
DIESEL ALL-Around Protection From the Refinery to the Engine
Refinery Transportation
Transportation Intermediate storage Supplying quality diesel equipment with clean/dry fuel benefits the organisation in several ways: ■ Improved diesel engine performance and reliability. ■ Improved diesel engine operating costs. ■ Reduced diesel engine maintenance costs. ■ Reduced vehicle downtime. ■ Reduced fuel consumption. ■ Reduced air pollution.
Hydac diesel filtration system.
this means you save costs in respect of reduced equipment repairs, lower levels of fuel consumption, and, of course, fewer major serious equipment failures caused by diesel contamination,” he says. ■
