Mining Homeostasis

Increased financial profitability based on operational sustainability.

How to reduce energy operating costs? How to address the energy transition to reduce our carbon footprint while ensuring clean, affordable, and secure energy?

Homeostasis as an agent of change!

Throughout our professional careers, a constant need has been the imperative adoption of new technologies to ensure continuity and/or survival in companies. Consequently, resistance to change arises, as it brings uncertainties about a future that can destabilize the existing status quo within the organization.The multitude of external factors beyond our control, coupled with internal resistance to change, serve to delay the decision to implement significant changes internally. Consequently, some companies hesitate to make changes until they realize that something is truly wrong, resulting in a significant and sometimes irreparable loss of their competitive advantages. In the words of Charles Darwin, «It is not the strongest species that survive, nor the most intelligent, but the ones most responsive to change.»In the mining sector, characterized by multimillion-dollar investments and demanding operational environments, the idea of incorporating technology that could jeopardize daily mine operations is strongly resisted. In some cases, this reluctance is based on outdated and unfounded fossil-based premises.Efficient and effective incorporation of hybrid solutions that primarily utilize renewable energy while including conventional energy for the mine has been conceived to ensure the necessary and reliable power supply for operations in extreme environments. This approach does not imply any operational risk as diesel generation is maintained as a backup and contingency scheme. The mining homeostasis we propose aims to break preconceptions, allowing executives to lead change and reap the multiple benefits that these hybrid solutions generate in terms of environmental, institutional, and operational improvements

Mining Environment – Energy:
Constant cost management as a consequence of global mineral prices. Inaccessible or impassable roads. Caution regarding capital expenditures (CAPEX). Remote and inhospitable locations. Ongoing focus on operational expenditures (OPEX). Extreme temperature conditions. Time-sensitive equipment maintenance. Living in isolated camps. High altitudes making breathing difficult. Continuous decline in commodity prices. Lack of infrastructure. Strong teamwork spirit. Deafening noise from diesel generators. Endless distances to populated areas. Enormous machinery crushing rocks. Diesel odor. Pressure from public opinion. Explicit mandate to preserve the environment.
Anyone involved in the mining sector can likely identify with some of the phrases mentioned above, which briefly depict part of the reality of mining. This reality demands and requires, to maintain an efficient production system, an adequate and necessary power supply that ensures safe, dispatchable, reliable, and affordable energy.
Globally, only 30% of mines are connected to the grid with sufficient capacity to meet their operational needs, while the remaining 70% are either off-grid or connected to weak and unstable power grids that do not meet the energy requirements of the mines. These mining operations are obliged to generate electricity using diesel backup systems, with costs that sometimes exceed $600 per megawatt-hour (MWh). Yes, there are places where generation costs, due to altitude and logistics, surpass this value.
The cost of energy, relative to total operation costs, ranges from 15% to 45% depending on the type of mine and whether it is connected to the grid or not.
Reducing electricity generation costs while preserving the environment, with the tangible and intangible benefits that this entails, is a priority on the agenda of many mining executives.
Effects of Diesel:
Mines are located in remote areas, often with serious accessibility issues. Supplying diesel fuel for the generation equipment installed at mines is not only a cost but also poses operational and environmental risks, creating significant logistical complexities. Logistic problems can compromise the power supply, and having fuel reserves to guarantee that supply increases production costs.
Diesel, an organic hydrocarbon, contains a certain amount of water that, when stored in a fuel tank, creates a favorable environment for the growth of microorganisms (bacteria, yeast, fungi), leading to the formation of biological sediments that can damage power generation equipment.
Diesel engine emissions, in the form of fine particles from exhaust, are a major source of air pollution, posing a significant health risk. In addition to the auditory and visual pollution caused by diesel-based electricity generation, it also causes irreparable harm to the environment through nitrogen oxides and greenhouse gases.
At high altitudes, diesel engines experience performance derating due to compression. This also leads to accelerated wear of diesel equipment due to inadequate working conditions. Additionally, two more problems arise: electrical insulation failures and equipment cooling failures.
There are numerous other unfavorable aspects related to diesel-based electricity generation. However, we will highlight one positive aspect that justifies the presence of diesel equipment in mining operations: contingencies and emergencies.

Description of the Smart Hybrid Microgrid with Storage (SHM):
The SHM is based on the combination of fossil generation technologies with clean and/or renewable energies in electrical grids. To achieve this, it is necessary to create a microgrid that controls the electrical dynamics of generation and consumption. This SHM is composed of electronic equipment that controls renewable generation, battery storage, consumption, and diesel groups that are always on standby (cold reserve) for operation. The graphic conceptually summarizes the components of the SHM.
Using state-of-the-art power electronics, all the necessary active and reactive energy management functions are performed to meet the system’s demand and absorb any events that occur, utilizing energy conversion based on direct current (DC) from solar sources and stored in batteries, into alternating current (AC), and vice versa.
The entire operation of the SHM is controlled by control equipment that manages the flow of energy. Each element of the SHM has a control unit that regulates its connection and disconnection. The control system must be very fast to anticipate network disturbances and ensure its stability, ensuring voltage and frequency.
Control is a critical element for the optimal and stable operation of the SHM. Each piece of equipment must be supervised and controlled for stable voltage and frequency operation, regulating power and demand constantly and instantaneously. A distributed architecture and the proven experience of all the solution’s components are important.
An additional advantage of the SHM is its rapid start-up speed. Depending on its size and complexity, commissioning and full operation can be achieved within four to fifteen months.
Another advantage of these solutions is their capacity to manage the mine’s energy matrix based on operations, existing resources, and business rules, integrating steam generation through Concentrated Solar Power (CSP) technologies with the necessary pressure and temperature conditions for the mine’s production processes.
The diesel group is reserved for situations where energy cannot be provided by the PV solar plant and/or batteries, or for zero-start situations, always remaining as a guarantee for the mine’s electrical energy operation.

Reliability of the Hybrid Solution (based on PV solar energy):
The renewable solar energy market, with over 300 GW installed worldwide, continues to thrive and is a fully mature generation alternative. Consequently, a primary objective of any photovoltaic energy system is to ensure continuous and reliable system operation.
Primary energy source: the sun. Although the solar energy received in one hour can power the world for a year, selecting the right location for the photovoltaic plant is crucial. More than 80% of mines in isolated areas are located within the solar belt (an area of optimal solar irradiation), guaranteeing the ability to predict solar radiation.
Solar resource: To calculate the correct solar irradiation, solar irradiation databases (e.g., Meteonorm and SolarGis) are used, ensuring accurate irradiation data.
Photovoltaic Plant Technology: To improve the plant factor and optimize photovoltaic production, solar trackers should be evaluated. Currently, the most cost-efficient option is the use of single-axis tracking systems. The received flat irradiation increases significantly (+20%) compared to global horizontal irradiation.
Electrical Equipment: Electronic and electrical equipment has a reliability of over 99% without moving parts, significantly impacting maintenance costs and available personnel.
Selection of Products and Components: The continuous pricing pressure in all parts of the photovoltaic energy supply chain has caused many traditional industry operators to be concerned about the long-term performance and reliability of photovoltaic components. While module reliability has received the most attention, balance of system (BOS) components such as inverters, electrical equipment, and structures should also be examined.
Therefore, top-tier suppliers (referred to as TIER_1) must be used.

Conventional and Robust Smart Hybrid Microgrids (SHM):
Conventional SHM systems have experienced exponential growth in the past ten years, driven by a significant reduction in component prices, increased knowledge among electrical service providers, a growing sustainable mindset, and, most importantly, the trust and reliability these solutions have demonstrated to their customers.
We refer to conventional SHM systems as those primarily designed to operate in environments where the electrical grid is present but with poor performance, such as areas with grid congestion. These systems are suited for moderate weather conditions, low energy storage requirements, simple logistics, and are connected to alternating current (AC).
On the other hand, robust SHM systems are designed to operate mainly in environments where the electrical grid is absent, extreme weather conditions prevail, high energy storage is needed, complex logistics are involved, and the system is connected to direct current (DC).
The architecture and performance of both types of SHM systems are the primary factors to consider when choosing between them.
The selection will depend on the specific environment where they will be installed. It’s worth noting that while robust SHM systems require a higher initial investment, their operational costs can be up to 30% lower, resulting in a similar overall cost in economic terms. However, robust systems offer clear advantages in terms of redundancy and resilience.
Energy Storage:
Renewable energies are dispatched when the resource is available (sun, wind, etc.); therefore, we recommend using an energy storage system to avoid the continuous operation of fossil generation equipment.
Depending on the amount of energy to be stored, the required power needs, and the time period in which the accumulated energy will be demanded, the appropriate type of energy storage system should be chosen: hydrogen, mechanical, electrochemical, electrical, or thermal.
For SHM systems, electrochemical batteries are commonly chosen. These batteries operate based on a reversible process called reduction-oxidation, where one component is oxidized (loses electrons) and the other component is reduced (gains electrons). It is a process in which the components are not consumed; instead, they change their oxidation state and can return to their original state under the right circumstances.
Three main characteristics define a battery: 1) the amount of energy it can store (Wh), 2) the maximum current it can deliver or discharge (A), and 3) the depth of discharge it can sustain. Commonly accepted battery chemistries include lead-acid, nickel-cadmium, and lithium-ion.
Each battery system performs best within a specific state of charge (SOC) range, and keeping the battery within this range can extend its lifespan. Batteries are designed for specific environments, considering factors such as high or low ambient temperatures. Proper temperature management is crucial for battery longevity.
In summary, not all batteries are the same. The choice of battery chemistry for energy storage systems depends on the desired performance or use of the stored energy, the geographical conditions where the MRH operates, the operational environment regulated by service quality, the expected return on investment, and, most importantly, the desired level of reliability.
SV-Concept:
At Green Cross UK, we promote the ASV-Concept as the first approximate model that allows presenting an energy project to an organization. It enables the analysis of the technical, economic, financial, and operational viability of the SHM compared to other sources of electricity generation, including diesel generation.
To exemplify the benefits of SHM compared to diesel generation, we will share some significant data developed for a mine with an installed capacity of 8 MW in an area with excellent solar radiation (+2200 hours), low average temperature due to altitude (<3000 meters), and a constant load profile throughout the 24 hours.
The results, obtained by simulating models with different degrees of renewable energy penetration in the hybrid solution, are compelling:
• Reduction in fuel consumption between 45% and 95%, equivalent to 4 to 13 million litres of diesel per year.
• Reduction in electricity costs between 40% and 60%, equivalent to 6 to 15 million dollars per year.
The modelled SHM not only guarantees the appropriate level of electrical service but also provides greater profitability to the mining exploitation project, contributes to carbon footprint reduction, and minimizes operational risks.
Benefits of SHM:
As we have developed, SHM allows providing secure, dispatchable, reliable, and affordable electricity, minimizing operational risks by using diesel generation as backup power.
The ASV-Concept concludes that the modelled hybrid solution for the mine will generate the following benefits:
Significant reduction in operational costs (OPEX) along with a substantial decrease in fuel costs.
Streamlined fuel logistics, avoiding truck accidents.
Extended diesel generation equipment inspection intervals and substantial simplification of rolling equipment maintenance.
Significant reduction in consumable maintenance items (filters, lubricants, etc.).
Long-term constant electricity costs through a Power Purchase Agreement (PPA), minimizing the risks of mining operations being tied to oil prices.
Electrical infrastructure with a lifespan exceeding 20 years, aligned with typically long-term mining operations.
Significant reduction in emissions and pollution.
Enhanced corporate image through the use of clean energy.

Conclusion:
We are pleased to share with you, dear reader, a summary of our extensive experience in the mining sector. Over the years, we have worked with major international mining groups on five out of the six continents, focusing on sustainability practices.
With numerous mega projects undertaken, we have demonstrated the viability of adopting these technologies. Therefore, we can confidently state that intelligent hybrid microgrids with storage, based on primary sources of solar, wind, or biomass energy, are the ideal alternative to reduce operating costs, preserve the environment, and ensure a reliable power supply in mining operations.
Lastly, to maximize the benefits, it is essential to approach the project within a framework of sustainable infrastructure. This will not only ensure the project is carried out correctly but also ensure that it is the appropriate approach, optimizing benefits and minimizing socio-environmental risks.
Autor / Author:
Ruy Campos-Dugone
Executive Director
Green Cross United Kingdom
ruycd@green-cross.org.uk