eStorage is a European consortium that is working to develop a solution based on variable-speed technology to increase the operational flexibility of hydro power plants and enable the cost-effective integration of intermittent renewable energy generation, such as wind, into the electrical grid, in support of SET-Plan objectives.
Backed by the European Commission with a grant of 13.3 million euros under FP7, the eStorage consortium, which is made up of major European stakeholders from the energy value chain, aims to improve energy management by developing solutions for the widespread deployment of flexible, reliable, GWh-scale energy storage across the EU and to enhance grid management systems to allow the integration of a large share of renewable energy.
The consortium consists of a multidisciplinary team, bringing together major European players from the entire electricity value chain, such as Algoé, Alstom, EDF, Elia, Imperial College London and DNV KEMA, with expertise covering electricity generation and transmission, research activities and impact studies, state-of-the-art hydro and grid technologies and project management. The project team is supported by an advisory board including the European Association for Storage of Energy (EASE).
The project’s objectives include demonstrating the technical and economic feasibility of upgrading an existing fixed-speed pumped hydro storage facility to variable-speed technology, which offers several advantages, including frequency regulation in generation and pumping modes. The technology also provides more operational flexibility for plant operators and makes flexible ancillary services available to grid companies. Furthermore, eStorage aims to enhance IT functionalities and to develop grid management solutions in line with real-time market systems and to quantify the benefits of an EU-wide rollout of variable-speed pumped hydro storage under alternative scenarios. The project also aims to propose changes to market and regulatory frameworks, to support appropriate business models for flexible energy storage in the EU and to develop and assess technology solutions allowing the upgrade of 75% of European pumped hydro storage to variable speed, in order to obtain additional capacity for flexible load balancing. The consortium will also develop and demonstrate solutions for coupling the dispatch of storage plants with renewable generation using advanced energy and market management systems, which will enable storage plants to maximise their value in the balancing markets.
“Variable-speed technology provides power regulation capabilities to utilities 24 hours per day which is critical for integrating intermittent renewables into the grid,” eStorage Project Coordinator Olivier Teller told SETIS. “Furthermore, upgrading an existing pumped hydro plant to variable speed is less expensive and faster to implement than constructing a new site. However, the upgrade can be complex because the variable-speed generator is larger than a fixed-speed generator. The eStorage project will demonstrate the feasibility of upgrading European pumped hydro energy storage plants to variable speed which could provide up to 10 GW of additional regulation capability should a significant portion be converted,” he said.
The cornerstone of the eStorage project will be upgrading EDF’s Le Cheylas fixed-speed pumped storage hydroelectric plant (PSP) to a variable-speed pumped storage plant. Once completed, Le Cheylas will provide 70 MW of additional night time regulation capability which will allow the integration of several hundred MW of intermittent renewable generation. This will demonstrate that a significant portion of European PSP capacity can be upgraded to variable speed, providing up to 10 GW of additional regulation capability with no environmental impact and at a much lower cost than developing new plants. The lessons learned from the Le Cheylas upgrade will help to enable the conversion of over 75% of European fixed-speed pumped hydro storage.
PSPs play an essential role in power regulation, allowing generating units to rapidly adapt their output to keep generation and consumption balanced at all times. Electrical production and consumption need to be balanced to ensure the stability and continuous operation of electrical networks. However, fixed-speed PSP plants can only provide power regulation in generation mode while variable-speed units can regulate power in both generation and pump mode. Virtually all existing PSPs in Europe are fixed-speed units. Adding variable-speed technology to pumped hydro storage power plants increases plant efficiency and flexibility by allowing power regulation in both turbine and pumping mode. It also enables electric utilities to harness surplus power from intermittent sources, like wind, to fill pumped hydro storage plants’ upper reservoirs faster, storing the surplus energy for later use when demand is high or when no wind energy is available. Coupled with improved IT systems, variable-speed technology will facilitate grid management for better real-time balancing of supply and demand.
From simulation studies, demonstration results and storage potential analysis, the eStorage consortium will evaluate the system-level benefits of storage and identify development barriers in order to draw recommendations for an efficient market and regulatory framework to maximise the impact of projects. The eStorage project will demonstrate the feasibility of upgrading to variable-speed technology, develop new IT systems for smarter grid management, put forward market and regulatory recommendations for energy storage, and develop scenarios for the rollout of energy storage across the EU.