ABSTRACT
Pumped Hydro Energy Storage (PHES) projects are major enablers to the world’s renewable energy future. These schemes store excess amounts of energy generated by renewable generators, in the form of stored water as potential energy, and release the stored energy over time back into the grid when conditions don’t allow wind or solar generation or when the grid needs immediate stability.
Tunnels and underground spaces are substantial elements of most large PHES projects, and the design, construction and operation of these underground elements need to be developed from the outset with strong environment, social and governance (ESG) considerations. The overall project, including the tunnels, should aim to meet several of the UN’s Sustainability Development Goals (SDGs). The ESG and SDG aspects have overlapping attributes under the project’s sustainability umbrella which must be considered across the lifecycle of the PHES (often in excess of 100 years) and these can only be influenced by an early design-stage focus on these topics.
Such projects will have multiple stakeholders, each having their own internal- and external-facing corporate requirements for sustainability and ESG. The project’s tunnel and underground space designers need to consider the range of perspectives of the varied stakeholders to achieve the goals. One useful tool to bring together multiple aspects of sustainability for tunnels is to assess the project under the Hydropower Sustainability Standard, a product of the Hydropower Sustainability Alliance, which is specifically aimed at addressing a range of 12 ESG-related items (of which at least 8 are directly relevant to underground features), and which are aligned to modern ESG requirements and several of the SDG goals. The International Hydropower Association’s How-To Guide: Hydropower Infrastructure Safety covers the hazard and safety aspects across a hydropower project lifespan, the key risk issues and provides commentary on tolerable risk limits and tolerable outcomes.
The paper explores the above topics from viewpoints of various stakeholders but with a focus through the lens of project lenders. It explains how PHES underground spaces can achieve compliance to meet lenders’ credit approval and overall sustainability objectives.
