This paper investigates the techno‐economic feasibility of the innovative concept of gravity energy storage, where heavy weights are raised and lowered in a water environment. Such eco‐friendly systems can be implemented in existing flooded pits or quarries, by leveraging the important depth of these cavities. Moreover, in addition to their long lifetime, they have no visual impact on the landscape, and offer a lot of flexibility to the power system. In this work, we firstly present an analytical study of the storage solution, which allows deriving tractable mathematical constraints describing its operation, such as its nonlinear speed‐power curves in both charge and discharge modes. These constraints are then integrated into the investment strategy of a merchant unit that seeks to maximize its profit by jointly participating in the energy and secondary reserve markets. The model is formulated within a stochastic framework to ensure robustness of sizing decisions in view of future market uncertainties. Results from a practical case study (on a natural cavity of 200 m) show that underwater gravity storage is a cost‐efficient technology that offers payback periods of less than 10 years, mainly due to its intrinsic low capital costs estimated at around 100 €/kWh.

中文翻译：

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具有固体重量的水下重力存储的大小参与电力市场

本文研究了重力能量存储的创新概念在技术上的经济可行性，该重力能量存储在水环境中可以增加或降低重物。通过利用这些型腔的重要深度，可以在现有的淹水坑或采石场中实施这种生态友好型系统。此外，除了使用寿命长之外，它们对景观也没有视觉影响，并为电源系统提供了很大的灵活性。在这项工作中，我们首先对存储解决方案进行分析研究，该研究可以得出描述其操作的易处理的数学约束，例如在充电和放电模式下的非线性速度-功率曲线。然后，将这些约束条件整合到商户单元的投资策略中，该商户单元旨在通过联合参与能源和二级储备市场来最大化其利润。该模型是在随机框架内制定的，以确保鉴于未来市场的不确定性而确定决策的鲁棒性。实际案例研究的结果（在200 m的天然空腔上）表明，水下重力存储是一种经济高效的技术，可提供不到10年的投资回收期，这主要是因为其固有的低资本成本估计约为100€/千瓦时