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ENERGY STORAGE A look at the main applications of energy storage systems

Author / Editor: Luke James / Johanna Erbacher

Energy storage systems are essential to the operation of power systems. With the growth of renewable energy sources such as wind, solar, and tidal power, their importance is continuing to grow. Here’s a quick look at some of the main applications of energy storage systems.

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The growth of renewable energy sources such as solar, wind, and tidal power has drastically changed the way we think about energy storage.
The growth of renewable energy sources such as solar, wind, and tidal power has drastically changed the way we think about energy storage.
(Source: gemeinfrei / Pixabay )

We’ve covered the challenges that face energy storage quite a lot at Power & Beyond; it’s one of today’s most pressing issues within the power industry. Indeed, the growth of renewable energy sources such as solar, wind, and tidal power has drastically changed the way we think about energy storage. They’ve also changed the model for large, centralized energy generators along the electrical system.

These days, there are more renewable energy resources dotted around the grid, located much closer to residential, commercial, and industrial areas. This is known as ‘distributed generation’ and it’s estimated that in the near future, it will become far more prevalent as we move away from centralized energy systems.

However, renewable energy sources such as the sun and wind aren’t predictable and cannot be controlled. They’re subject to sudden changes which makes them inherently less reliable, and their integration with existing thermoelectric plants is far from an easy task.

To respond and adapt to the changes brought about by increased levels of renewable energy generation, we’re going to have to change the way we manage the electrical system, and a big part of this will rest on realizing a suitable long-term energy storage system that can support the integration of renewable energy sources.

The applications of energy storage systems

To put things into perspective, here’s a look at the main applications of energy storage systems:

Energy arbitrage
In markets where there is a difference in locational marginal price of electricity at different times, energy arbitrage can be used to offset costs. When the price is low, wholesale electricity is purchased and stored. It’s then resold when the price is high. While arbitrage is not typically a profitable storage application in its own right, with some losses occurring during charging and discharging, it can be combined with others by value stacking.

The benefits here are not strictly related to economic advantages (i.e., buying low, selling high). Rather, energy arbitrage or ‘energy moving’ contributes to increasing the energy demand when it’s low and decreasing it when it’s high. This leads to “peak shaving” and reduces the impact of peaks in both the generation and load curve, resulting in a smoother, more predictable curve.

Frequency regulation
The power grid transmits electricity from generators to users at a fixed Alternating Current (AC) frequency. This varies, but in Europe, it’s generally 50 Hz. When power generation is equivalent to power usage, the frequency is stable. Where usage is higher than generation, however, the frequency drops and can lead to blackouts. Where usage is lower than generation, the frequency rises, and this can damage the grid and any devices connected to it.

Frequency regulation regulates supply and demand to keep the AC current within the required tolerance bounds. As more renewables are connected to the power grid, however, the variability and fluctuations in frequency are more common and severe. In response, generating assets are typically ramped up or down to provide control.

Voltage support
As well as regulating frequency, grid operators must ensure a certain voltage and that voltage stability is maintained. To do this, they manage grid reactance via an ancillary service known as voltage support.

Reactive power can only be transmitted over short distances which in the past has limited its utility. Given that distributed energy storage is located much closer to end users, however, they become an attractive option for voltage support.

The future of energy storage systems

As we’ve briefly explored, there are many applications for energy storage systems that bring several benefits for the power system. Over the next few years, however, it’s battery energy storage systems that have the most growth potential and are likely to bring us a much-needed workable solution for grid-scale renewable energy storage.

The benefits of a battery energy storage system are many. The most prevalent are:

  • Ease of integration into existing power plants.
  • Ease of installation.
  • Useful for both high-power and high-energy applications.
  • Much smaller when compared to other storage systems.
  • Lower price barriers.

At present, a substantial amount of research is going into finding a way to store renewable energy in a universal and inexpensive way. This is proving to be a challenge, however, but with great strides in battery technology being made with each passing day, we may soon see a viable solution.