country FOCUS p l a n t s h a v e t h e a d v a n t a g e t h a t construction time is extremely short. Solar energy can be very cost efficient in Zambia. �e bid tariffs for two 50 MWp PV plants start at US ¢ 6.02 / kWh16 and are thus well below the power costs that the Zambian government had for emergency measures and below the new energy tariff for mines of 10.35US ¢/ kWh17 that is expected to constantly increase over the coming years. �e solar power plants could be either built centralized and provide power through the grid or decentralized, i. e. in proximity of a mine with a direct power line to the mine. In the second case, the solar power plant would be part of a microgrid. Back-up diesel gensets or stationary energy storage such as batteries could also be a part of the microgrid which is also called solar-diesel hybrid power plant. In recent years, the technical feasibility of electricity generation for mines through solar powered microgrids has been proven as well in large scale applications. 18 Connecting the mining microgrid to the national power grid might be advisable as diesel genset usage can be reduced considerably. In the microgrid, diesel gensets are very likely to be the generator with the highest direct costs and with the biggest environmental impact. In the gridconnect microgrid scenario diesel generators provide only missing gap between the solar output and the load from the mine which is not available from the grid. �is might be the case during loadshedding. �e objective of the microgrid is to provide robust and stable power to the mine. Energy storage solutions, e. g. in the form of batteries, can further stabilizes the microgrid by shaving peak loads and providing peakpower. Critical processes are o�en secured with UPS-system already today. Some manufacturers aim using the UPS storage system for the microgrid. �e combination of microgrid and national power grid might also have additional advantages in the future. If the solar power plant generates more electricity than the mine consumers, the energy might be fed back into the grid. �e decentralized microgrid solution ensures that the grid is utilized less by the mine. �e current power crisis in Zambia presents a chance for solar energy. Many mining companies see the risk that arises from power outages and load shedding in form of higher energy costs or production losses. Electricity costs are expected to further raise in Zambia. A�er a long period of inexpensive energy from abundant hydro power the paradigms have changed in Zambia. Solar power can be installed extremely quickly and can contributed to save costs in comparison to power from expensive back-up diesel gens ets immediately. Energy costs advantages can be an important differentiator in the very competitive copper market which be characterized by supply surplus due to falling copper demand from China. More and more mining companies have a strategic look at energy.
FMDZ | Jan- Feb 2017 | Page15