LONG DURATION ENERGY STORAGE (LDES)
WHAT IS LONG DURATION ENERGY STORAGE (LDES)?
The Pakri Peninsula Energy Storage is like an underground hydroelectric power plant, functioning as a gigantic electricity storage facility. When the wind blows and the sun shines, it can pump seawater out using this cheap electricity. When there’s no wind and the weather is cloudy, it can use turbines powered by seawater. The water storage solution is a way for Estonia to transition to 100% independent renewable energy, and in the future, it will result in lower electricity prices for consumers and a smaller carbon footprint.
LONG DURATION ENERGY STORAGE (LDES)
Energy storage systems can be divided into two categories: short-term and long-term. Short-term energy storage lasts for a few minutes or hours to address rapid fluctuations in the electrical grid, such as frequency regulation or covering peak loads. Batteries and accumulators are examples of systems used for such tasks. Long-term energy storage refers to technologies that allow energy to be stored for extended periods – typically from several hours and days to weeks or months. This is necessary to balance long-term variations in renewable energy production, such as seasonal fluctuations in wind and solar energy. The most common method for this is the storage of water energy using two bodies of water at different elevations, with a pump station located between them.
How does a water storage system, also known as zero terrain, work?
In a water storage system, energy is produced when seawater is passed through turbines into reservoirs built 750 meters deep. When wind turbines and solar panels generate more electricity than is consumed – i.e., when electricity prices are low – seawater previously pumped into the reservoirs is returned to Paldiski Bay, thus storing energy. During a 12-hour work cycle, the Paldiski water storage system can deliver 6 million kWh of previously stored electricity to the grid, which exceeds the average daily electricity consumption of Estonian households. Starting from 2038, this capacity will increase even further to 15 GWh (30 hours). The Paldiski water storage system allows for the storage of up to 1.2 TWh of renewable energy annually, ensuring stable and dispatchable electricity supply. The total capacity for long-term storage reaches 500 MW. Without water storage, renewable energy sources like wind and solar would only be half of the equation in bringing lower electricity prices and a smaller carbon footprint to Estonian consumers. The large volume, long storage period, high efficiency, and relatively low operational cost per unit of energy give the electricity system various advantages. For other questions related to the Energy Storage, you can find answers here:
