CRUX Underground Energy Storage Container

  • Distribution
  • Storage
  • Balance of system
  • Energy storage
  • Durability

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CRUX Engineering

Published 06 Feb 2017

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CRUX Underground Energy Storage Container

Our solution is an underground storage container in which compressed air or compressed biogas can be stored in decentralized energy systems. The containers will be placed at depths between 50 and 150 m and can contain 500 to 10.000 m3 of compressed gas. The internal pressure will be in the range of 10 to 100 bar. The container is the “energy component” of a Compressed Air Energy Storage system (CAES). Biogas can be stored in the CRUX container for later use in order to better match the gas demand. The principle of the container is to used the soil pressure to contain the internal gas pressure. The container has a flexible wall in order to mobilize the soil pressure. An impermeable membrane separates the inner and outer pressures. An internal stability structure, for instance made of bio-composites, secures the stability of the system when the internal pressure is low. Using the earth to counterbalance the internal gas pressure has the main advantage that it is scalable. Steel containers do not scale with size. When the volume increases or the internal pressure increases, an equivalent extra amount of steel is required, which means that costs ($ per kWh) will not decrease. CRUX containers do scale with size, as the main material of which the container is made, the earth, is already in place. This means that for CRUX containers the $ per kWh decreases with an increasing volume or pressure.

How it benefits society

The problem we aim to solve is the mismatch between intermittent energy production and fluctuating energy consumption. For electricity, the mismatch is due to irregularities of both production and consumption. Biogas generally has a continuous production, so the intermittency is mainly on the consumption side. The storage systems should primarily be beneficial to the owners and/or operators of the storage system. At the moment it is not fully clear, at least not in The Netherlands, who is responsible for an energy storage system. Storage systems can be used for price arbitrage (buy low, sell high), but also to secure the reliability of the energy systems of which the storage system is a part of. In the end the solution should be beneficial for society as a whole as it will support the increasing and effective use of renewable energy sources. Energy storage is an essential component in a society based on 100% renewable energy. I know that the solution will be a success because the principles of the solution are simple and the momentum is there. The process of combining the geotechnical, energy and legislation worlds is the biggest hurdle to take…

Who we are

CRUX Engineering
Jacco Haasnoot, Almer van der Stoel PhD, Holger Netzel PhD
Amsterdam / Delft / Eindhoven, the Netherlands

I (Jacco Haasnoot) am a mining engineer involved in underground construction ever since I graduated from Delft Technical University in 1995. Initially I worked for Dutch consultants on high profile projects such as the North/South Metro Line in Amsterdam. In 2002 my former metro colleagues started CRUX Engineering, which I joint in 2005. Within 15 years we have made CRUX the leading geotechnical consultant in the Netherlands. CRUX employs about 35 people and is a healthy and profitable enterprise. CRUX has grown to the present size with consultancy specialised in geotechnical engineering as its main product. Since a few year we also develop "geotechnical products" in order to let our business grow. We use our geotechnical know-how and brain power to develop concepts and products to create value. We are involved in underground heat storage, enhanced dike safety analyses, innovative deformation monitoring techniques and sustainable composites products based on bamboo fibers. With bamboo fiber composites we are part of a business accelerator program. Especially this product development gives me energy. Finding smart solutions for actual problems is what excites and challenges me and us at CRUX. We think and know from past experience that we the expertise and energy to develop new business. We also know that we cannot do this alone.

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