Energy Storage Technologies: The Key to Mitigating Curtailed Renewable Energy

The nature of solar and wind energy generation leads to fluctuations in supply, resulting in curtailment or wastage of excess energy. To address this challenge, energy storage technologies have gained prominence in recent years, offering a viable solution to mitigate curtailed renewable energy. In this article, we will delve into the various energy storage technologies available today and their role in ensuring a smooth and uninterrupted renewable energy supply.

The Need for Energy Storage Technologies

Intermittency, or the fluctuations in energy generation, is a critical challenge faced by renewable energy sources. Solar power generation depends on sunlight availability, which varies throughout the day and is affected by weather conditions. Similarly, wind power generation relies on wind speed, which is uncertain and inconsistent. As a result, excess energy is often curtailed, leading to wastage and reduced efficiency.

Energy storage technologies provide a solution to mitigate curtailed renewable energy by storing excess energy during periods of high generation and releasing it when there is low or no generation. This enables a more reliable and stable energy supply, ensuring the smooth integration of renewables into the grid.

Types of Energy Storage Technologies

Battery Energy Storage Systems (BESS)

Battery Energy Storage Systems (BESS) have gained widespread attention due to their versatility and scalability. Lithium-ion batteries, in particular, have emerged as a dominant technology in the BESS market, offering high energy density, efficiency, and long lifespan. BESS can store excess electricity generated from renewable sources and discharge it when demand is high or during periods of low generation. They are widely used in grid-scale applications and provide key benefits such as:

  • Smooth power output by stabilizing fluctuating renewable energy supply.
  • Time-shifting renewable energy, allowing utilization during peak demand hours.
  • Enabling grid stability during blackouts or periods of high demand.

In fact, according to the International Renewable Energy Agency (IRENA), the global capacity of installed energy storage is expected to increase from around 10 GWh in 2020 to a staggering 6,845 GWh by 2050, with Lithium-ion batteries dominating the market share.

Pumped Hydro Storage

Pumped Hydro Storage (PHS) is one of the oldest and most mature energy storage technologies. It works by pumping water from a lower reservoir to a higher reservoir when excess energy is available and releasing the water through turbines to generate electricity during periods of high demand. PHS offers several advantages:

  • Large-scale energy storage capacity, capable of storing gigawatt-hours of electricity.
  • Long operational lifespan with minimal degradation over time.
  • Fast response time, making it suitable for balancing sudden changes in power demand.

PHS currently accounts for the majority of installed energy storage capacity worldwide, contributing approximately 95% of all storage capacity, according to the U.S. Department of Energy (DOE).

Thermal Energy Storage

Thermal Energy Storage (TES) technologies store excess energy in the form of heat or cold and release it for useful applications later. Many TES technologies exist, including phase change materials, molten salt, and chilled water storage. They are commonly used in several sectors, such as manufacturing, commercial buildings, and district cooling systems. Key advantages of TES include:

  • Efficient utilization of waste heat or cold, reducing energy consumption.
  • Balancing energy demand and supply by shifting energy usage to off-peak hours.
  • Enhancing the efficiency of renewable energy systems by providing continuous supply.

Building-integrated thermal energy storage systems are gaining attention as a sustainable solution for cooling and heating in smart cities, contributing to energy efficiency goals.

The Future of Energy Storage Technologies

As the world strives to transition to a cleaner energy future, energy storage technologies are poised to play a crucial role in enabling the integration of renewable energy sources. With advancements in battery technologies, the cost of energy storage systems is steadily declining, making them more accessible and economically viable. Additionally, research and development efforts are focused on improving the efficiency, scalability, and sustainability of energy storage technologies.

According to Wood Mackenzie and the Global Wind Energy Council, the global energy storage market is expected to grow exponentially, reaching 741 GWh of annual capacity additions by 2030. This growth will be driven by factors such as supportive government policies, declining costs, and increased renewable energy penetration.


Energy storage technologies are the key to mitigating curtailed renewable energy, ensuring a smooth and uninterrupted supply of clean electricity. Battery Energy Storage Systems, Pumped Hydro Storage, and Thermal Energy Storage provide viable solutions to store excess renewable energy and release it when needed, enabling grid stability and efficient energy management. As the world continues to embrace renewable energy sources, the evolution and widespread adoption of energy storage technologies will contribute significantly to a sustainable energy future.

For more information on energy storage technologies, visit the U.S. Department of Energy’s informative guide on Grid Energy Storage.