UK-based gravity energy storage firm Gravitricity and electrification and automation company ABB (<a href="https://www.six-group.com/en/products-services/the-swiss-stock-exchange/market-data/shares/share-explorer/share-details.CH0012221716CHF4.html#/" target="_blank">SWX:ABBN</a>) have signed a memorandum of understanding (MoU) to explore the use of hoist technologies to advance gravity energy storage systems in former mine shafts, according to an announcement today.