Mine Storage builds grid-scale energy storages using pumped storage technology in underground mines. A question that we sometimes get asked is how we evaluate if a mine is suitable for a mine storage. The answer is complex, but we have tried to summarize some of the most important aspects in this article.
One of the major challenges when prospecting traditional pumped storage plants above ground is finding suitable locations. Traditional pumped storage requires natural height differences and the (often large) effect that the storage has on the habitat and biodiversity make getting approval to build the pumped storage facility difficult.
One of the most attractive benefits of mine storages is that the possibilities multiply by looking at mines and the height difference they offer below ground.
The exact number of mines in the world is difficult to define, as a mine can consist of different mining systems and shafts. It is estimated that there are approximately 1 million abandoned mines in the world. There are approximately 161 000 abandoned hard rock mines in the western US alone. (ref: US Government Accountability Office GAO)
Mine Storage has developed a mine grading and qualification process to efficiently find the most suitable mines for grid-scale energy storages.
Screening and grading a mine start with data collection of mining and energy system data from public sources. The initial assessment includes mapping the location of the mine compared to the electric grid since mines that are far off grid are more expensive to build. We also look at what type of mine it is. Hard rock metal mines are more suitable as a mine storage compared to, for example a coal mine. In addition, different metal types will affect the water quality which has implications for the construction of the mine storage.
The depth – or head in relation to the available volume for the water reservoirs sets the maximum power effect and discharge time for the energy storage. The water situation of the mine can differ hugely depending on the location. Some mines fill up with water so that too much water becomes an issue. Other mines are dry and being able to access water to use for the energy storage is the issue. Access roads and ramps are other aspects that can have an impact on the cost of construction.
Based on this information the mines are shortlisted for the next step, which is the mine qualification stage.