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Flexible Grid Scale Energy Storage

Energy Storage is Key in the Green Transition

Decarbonization and electrification are driving a massive change in our energy system

Decarbonization and electrification are driving a massive change in our energy system

Mine Storage provides a storage solution with a unique, modular design, and reliable functionality. Our design is a fast response, closed loop system in old mines. By using mines, we minimize the environmental impact, reduce construction costs, and utilize existing infrastructure such as grid connections. The availability of sites in the world is significant, as it is estimated that there are more than 1 million closed mines with no current purpose.

We use modern modular technology from established providers adapted to meet the requirements of today’s markets. Our solution is always designed based on how revenue will be generated. Mine Storage is a suitable solution for both bulk storage and ancillary services. For each mine storage plant, the operational model is developed to optimise the revenue based upon the conditions of the local market.

We need more clean energy now

Supporting a sustainable future with abundant energy 

Electrification and decarbonisation requires us to exponentially increase our renewable electricity production over the coming decades. 

Electricity grids are real-time-systems that constantly need to be fed with the same amount of electricity that we consume.

Today, only 3 % of all generated power is stored. To enable the energy transition the world needs grid-scale energy storage.

Using water and gravity to store energy is one of the most mature and widespread technologies for energy storage available today. In fact, more than 90 % of the current grid-supporting energy storage is based on water and gravity.

Using abandoned mines has several benefits on different levels. It enables hydropower energy storage facilities to be built in places without height differences in the landscape. It lowers the construction cost and the environmental impact given that existing infrastructure can be utilized.

A mine storage can vary in size from 15 to 200 MW and in discharge time from 2 to 12 hours, depending on the need in the area where it is located.

To put this in context, A 100 MW facility can provide a city of 250,000 households with energy for up to 12 hours. Each facility is tailored to the local market and requirements, ensuring that it serves its purpose and that it is financially sustainable.

To support a zero-carbon grid, we need to adjust for production gaps and smaller fluctuations in production and consumption. This is where solutions such as demand flexibility and short-term energy storage comes in.

A mine storage can be used both for grid-scale and short-term storage, thereby addressing both the production/consumption mismatch and the stability of the grid. In other words: mine storages can be the key that enables the transition to green energy.

Technology presentation

Flexible Grid-Scale Energy Storages
Mine Storage Explainer
A mine storage has grid-scale energy storage capacity and can discharge energy for 2-12 hours. Sizes can vary between 15-200 MW // 30-2 400 MWh.
A mine storage has a high round-trip efficiency of 75-85 % depending on size and configuration.
An Energy Swiss Army Knife
A mine storage supports the energy system in several ways, often simultaneously. It can act as energy storage, grid frequency regulator, capacity reserve, transmission support, inertia provider, or as a behind-the-meter solution to support large energy producers or energy-intensive industries.
A mine storage utilizes water and gravity with proven, durable equipment such as pumps, turbines and generators, enabling it to stay operational for 40-80 years with only smaller equipment refits.
Turning an abandoned mine into a mine storage turns it from a liability into a circular asset.
Low Cost of Storage

Given the compelling business case, the high round trip efficiency and the long lifespan of a mine storage, the levelized cost of energy storage (LCOS) is very competitive. 

Many Available Sites

There are more than 1 million decommissioned mines in the world, fairly evenly spread out, meaning mine storages can be built to support the energy system in most regions. Generally, it is the regional demand for energy storage that limits the number of mine storages, not the availability of suitable mines.

Low Local Impact and Safety by Design
A mine storage in operation is hardly noticeable for its neighbors. Most of the facility is underground, meaning it can’t be seen or heard. The best indicator of the existence of a mine storage is that the water level in the upper water reservoir varies slightly.

We use the cleanest means of storage – WATER

We use the most basic law of nature - GRAVITY

Mine Storage uses the same proven technology as traditional pumped storage, but applies it in an innovative way by using the height difference that you can find in decommissioned mines. It is the amount of water in the mine that governs the amount of energy that can be stored. When building a mine storage, the mine itself becomes a circular asset that supports cost effective abundant clean energy.

The mine site already has an industrial past and we can re-use infrastructure that is already in place. No dependence on rare-earth metals. No worried about recycling of batteries. Just water and gravity. 

Mine Storage Explainer Video
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Business for a renewable world

growing demand for energy storage

Today, only 3 % of all generated power is stored which will need to increase exponentially. To enable the energy transition 660 billion USD will be invested in energy storage by 2040. 

globally scalabe solution

Over 90% of current grid-supporting energy storage is represented by water-based solutions. In other words, water and gravity plays the most important role if we want to find a solution that is mature and can be scaled to reach the global demand for energy storage.

building circular value chains

Mine Storage uses the same proven technology that you see in traditional pumped storage, but applies it in an innovative way by using the height difference that you can find in mines. By building mine storages we build circular value chains. The idle mines become utilized as well as the adjacent existing infrastructure.

environmentally & financially sustainable

A mine storage provides a profitable business case and a low LCOS. It can receive its revenues from many different sources, from energy trading, ancillary services, grid-supporting services or applied behind the meter to support large energy producers or consumers.

Frequently Asked QuestionS

A mine storage uses the cleanest media, water, and the most reliable power, gravity, to accomplish an energy storage system. The height difference between two reservoirs is what allows for energy to be stored by pumping water from the lower to the higher reservoir, and later released by the water passing the power equipment in the machine hall. 

Mine Storage uses the same proven, state-of-the-art technology as traditional pumped storage and hydropower plants. The main components are turbines, pumps, generators, motors and switchgear and associated control and protection equipment. Mine Storage has a partnership with Voith Hydro, one of the three big global manufacturer and suppliers of this type of equipment.

The round-trip efficiency is typically ranging between 70-85% depending on the design of the mine storage and the selected machine configuration.

There are roughly a million closed mines registered in the global database mindat.org. All of them are not suitable for mine storages, but the availability of mines is not a limitation. On the contrary, they have significant global spread, and we also see opportunity for the use of mines still in operation.

Mines with a minimum of 50 meter, “head”, which is the expression for height difference in the hydropower industry, can be suitable. The size of reservoirs depends on several parameters, most importantly for which application we plan to use the mine storage. The mines are assessed as part of our Mine Storage WoW (Way of Working) that also includes looking at parameters such as mine type, design, proximity to a grid connection. We use our mining expertise in the mine assessment. Different mines may require different measures as part of the physical conversion to a mine storage.

The system is basically a closed loop, but some interaction with the surrounding environment can be expected, both in- and outflows. This means we have to assess and take measures related to this interaction as part of the project EIA (Environmental Impact Assessment), in the permitting process, and later during operation.
We combine in-house competence with external technical, environmental, and legal expert resources as needed.

All our business development is based on finding profitable business cases. Given that there are different revenue opportunities and different needs on different markets we have no fixed size limits. There are no limitations in size from technical point of view, and the beauty of mine storage is that the increase of energy is water and reservoir space, thus low-cost components compared to other energy storage systems.

One strong market position for a mine storage is grid-scale energy storage (15 MW up to several hundred MW). Regarding energy ratings, we typically see 50 MWh as the lower starting point and again, the business case defines how high we go.

There are differences between countries, but the most common principle is to engage with the responsible grid company in the geographical area. The required voltage level will depend on the power rating and intended operation of the mine storage.

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