The mining industry can significantly reduce its diesel fuel consumption when developing new mineral deposits by using microgrids with renewable energy sources: this is the conclusion of a study on “Mobile Solar and Wind Diesel Hybrid Solutions for Mineral Exploration”.
CrossPower, developed by Pfisterer, is a hybrid and mobile energy system for setting up microgrids combining conventional and renewable energy sources. It is ideal for the requirements of exploration teams and is also scalable for the stationary supply of entire mines.
Supplying power to remote exploration camps is a significant cost factor in mineral exploration. This is because diesel fuel for generators must be transported over large distances, sometimes even by helicopter. Renewable energy has become much cheaper over the last decade – but conventional installations are designed for an operational lifespan of at least 25 years. This is incompatible with the short-term needs of exploration teams, who only ever explore for new mineral resources for a short period at one site. At such an early stage of the mining process, there is no guarantee of finding sufficient deposits to justify a commitment to substantial infrastructure with long-term obligations. Pfisterer – the leading manufacturer of fittings and accessories for underground cables and overhead lines – and consulting firm THEnergy, therefore, conducted a study on “Mobile Solar and Wind Diesel Hybrid Solutions for Mineral Exploration” to investigate solutions that utilise the savings potential of renewable energy in the exploration process. The conclusion of the study is as follows: Exploration companies want power solutions that are reliable and can be used at more than one site. Military applications have similar requirements. The CrossPower system won a highly coveted NATO contract, and is already successfully in use since over one year for the NATO Energy Security Centre of Excellence. This system has a rated output of approximately 150 KW (or up to 2,500 kWh per day), a storage capacity of 100 kWh and comprises a control unit, high-performance batteries, a wind turbine and solar panels as well as two diesel generators. All components can be transported in two 20’ ISO containers for mobile use.
Mobile microgrid container
The CrossPower Small Grid (SG) energy system that Pfisterer developed for mining exploration is based on the same proven CrossPower technology. Transportable microgrid containers that are easy to install and remove form isolated energy grids combining photovoltaics and wind turbines with conventional diesel generators. This configuration is thus the first of its kind to offer reliable, renewable power in search of raw materials. Before the CrossPower system was launched, diesel generators were the only reliable units capable of providing a steady source of power in this application. Delivering fossil fuels to remote areas, however, is very expensive and a risky endeavor.
Reliable and economical
In developing its system, Pfisterer set itself two main targets: Diesel savings by more than 50 percent at each installation and a return on investment in 2–3 years with a minimum installation life of 10 years or more. CrossPower combines hybrid power generation with an intelligent management system. This guarantees a highly reliable power supply even on a cloudy or windless day. Modern lithium-ion batteries store the renewable energy, which is automatically prioritised by the management system. Diesel generators charge the batteries only as required, and therefore operate in their optimum output range. This cuts fuel consumption even up to 75 percent – more than initially expected – and makes the system remarkably efficient. Since much less diesel is needed, the number of cost-intensive fuel shipments is reduced at the same time. Comparison of the NATO systems in Lithuania over many months has shown that even without supply of regenerative energy using the CrossPower systems, a fuel-saving of 20 percent can be achieved simply through the operation of generators at their optimum performance range. Over-capacity is stored temporarily by the battery.
System Design
At the heart of the system is an intelligent energy management solution that provides a stable supply for microgrids and allows energy to be used in a resource-friendly manner. The backbone is a lithium-ion battery storage component with a microgrid-compatible inverter. This provides an autonomous supply grid to which a wide range of generators can be connected. Photovoltaic systems and wind power are suitable renewable energy sources. Existing diesel generators can also be connected to the system. In addition, the system can operate in grid-connected mode to compensate for supply gaps in unstable grids. The battery storage makes up the difference between the generated and consumed power. Therefore modern lithium-ion batteries are used. Compared to lead acid batteries, these offer maximum flexibility, a long product life, and a high degree of cycle stability, thus making them particularly suitable for multiple charging/discharging cycles as required in grid stabilisation.
Consequently, the installation provides a stable and constant sinus wave voltage, this is essential for the safe operation of critical IT systems, for example, whereby the output voltage and frequency can be selected in accordance with the local requirements. All common voltages and frequencies are possible, such as 230 V and 400 V at 50 Hz or 110 V and 120 V at 60 Hz.
Stable Power Supply Guaranteed
The primary task of the control software is to guarantee grid stability in combination with optimum energy efficiency. Intelligent energy management prioritises renewable energy sources according to their availability. The diesel generators cut in only when required to charge the batteries. If the solar or wind power drops temporarily, the control system uses the batteries until they reach a minimum level before it switches to fossil energy sources to safeguard the base load. The various energy sources and the battery are generally designed and dimensioned in such a way that fossil fuel energy savings up to 75 percent is achieved, thus ensuring short amortisation periods. In the vicinity of the equator, savings of more than 80 percent are even possible. When the diesel generators are switched on, they always operate at their optimum output range and never under partial load thanks to the existing battery buffer storage. In conventional generator systems, on the other hand, the fluctuating load of the current consumers determines the level of efficiency and the wear and tear.
Scalable size – up to the powering of entire mines
CrossPower is available in different sizes, tailored to customers’ individual needs. These range from mobile systems with 25 kW to 250 kW for exploration teams to the stationary CrossPower Large Grid (LG) with a power of 5,000 kW and more, which even enables entire mines to be powered. The system is always designed for easy transportation in containers. Each facility’s final system design depends on the level of the output power and is always geared towards the customers’ individual requirements. This applies to the energy mix as well as the size and number of containers. Naturally, several systems can also be operated in parallel.
Easy to Use and Maintain
The task of meeting the requirements of a reliable power supply in remote regions is extremely challenging: The systems involved must supply power reliably around the clock by utilising energy sources available on site and must be suitable for mobile deployment. Success therefore hinges on interface management between the various electricity producers and consumers. Mobile power grids can be built rapidly and reliably without specialists through the use of modular plug-and-operate components. With almost 100 years of experience and around 2,700 employees, Pfisterer is one of the world’s leading technology companies for system solutions and components in power transmission. Since its founding in 1921, the Group headquartered in Germany has been developing, manufacturing, and distributing internationally successful solutions for 110 V to 1,100 kV voltage levels.
CrossPower installations were designed using experience from numerous grids worldwide. The entire system is based on a touch-safe design and can be operated in the close vicinity of equipment and tents. The control panel has a straightforward, intuitive graphical user interface. It shows at a glance the direction of all energy flows and their intensities. No permanent staff is required on site during operation. The control system has been designed in such a way that it can respond independently to changes. Furthermore, the systems can be maintained remotely. Various performance data can be accessed via an encrypted and secure connection (VPN). Operating parameters can also be optimised accordingly. Remote maintenance is carried out via a 3G module and is therefore possible using all cell phone networks worldwide.
High Potential for Minimising Fossil Fuel Consumption
The true showpiece of the CrossPower system is the reliable power supply offered to remote settlements, small islands, mining explorations, and hotels, which are often powered by diesel generators as it is simply too expensive to erect a conventional power supply grid. The International Renewable Energy Agency (IRENA) estimates that the total output of all diesel generators currently operated worldwide is approximately 400 gigawatts. Integrating renewable energy sources with the CrossPower system can offer enormous energy-saving potential in this area.
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