Skip to main content

Enhancing Resilience and Stability

Published by , Editor
Energy Global,

The transition to a more sustainable energy future is well on its way. Global electricity demand is expected to more than double in the coming 30 years, making electricity the backbone of the entire energy system and accounting for more than half of total energy consumption by 2050.1

Renewables are central to that transition, representing more than 80% of new power generation capacity installed today.2Of renewable energy sources, solar is the fastest growing, registering a 19% increase in capacity in 2021, equal to 133 GW.2 By 2050, solar is expected to account for approximately half of all electricity generation.

Power quality is key

With so much variable solar generation in the power system, the grid connections that transfer electricity from the solar energy plants to the grid need to include additional power quality technologies alongside the traditional combination of switchgear, transformers, as well as protection and control.

This is because of increased requirements for reliability and flexibility, as well as the need to provide services to the power system that were previously provided by fossil fuel-fired power plants that some countries are now shutting down. Previously, when renewables represented a small share of power generation, the quality of that power was not critical; now, renewable energy plants need to operate with the same power quality as traditional generators.

The technologies that are becoming more common in solar grid connections are static synchronous compensators (STATCOMs), synchronous condensers, battery energy storage solutions, advanced energy management systems, and modular prefabricated grid connections.

These technologies are already available. The benefits they provide are crucial for power system quality and reliability. This includes better control of electrical parameters; improved voltage dynamic behaviour, frequency, and active and reactive power; increased short-circuit levels at the connection point; adding more inertia to the power grid; and faster, simpler, and more efficient grid connection solutions thanks to modularity and prefabrication. In short, these technologies enable the power grid to become more resilient and operate in accordance with compliance requirements.

Keeping the grid stable

The first group of requirements is related to inertia and short-circuit power. The inertia of the power system is traditionally provided by large electrical generators. When traditional power plants close down, there are fewer synchronous rotating masses in the power system, which weakens system resilience. In a weaker power system, the frequency is less stable. This can be solved by adding synchronous condensers, in some cases with additional mass in the form of a flywheel. For example, in the UK, Hitachi Energy has pioneered the combination of a synchronous condenser with a STATCOM to improve inertia and short-circuit power.

This world-first installation at an SP Energy Networks’ grid connection in Scotland proves that a machine with a flywheel increases the inertia of the power system. If a fault occurs, the solution feeds it with short-circuit current. The result is a stronger network, which in combination with the fast voltage control of the STATCOM further improves the dynamic behaviour of the system.

Energy storage

The second group of requirements is linked with the active power of the solar plant and its response to demand from the grid. Solar plants have predictable but variable generation and do not inject power into the grid at night. By combining energy storage with advanced energy management systems, the variability can be controlled and power can be delivered optimally when the sun is not shining.

Examples of solar power with energy storage are now very common, such as the combined solar and energy storage solution for Skagerak Arena football stadium in Norway. Battery energy storage with advanced grid automation helps the system optimally deliver the solar power generated to both the stadium and the neighbourhood when solar generation is low.

Additionally, it reduces peak demand on the nework by automatically releasing the energy when needed.

Improved power dispatching is also achieved by larger solar plants, such as the Al Badiya 23 MW solar power plant in Jordan, which has 23 MW/12.6 MWh of battery energy storage. By using advanced power plant control, it is able to shift generation from noon to the evening, delivering the solar power when it is needed most.3

To continue reading this article from Energy Global’s Winter 2022 issue, click here.

Don't forget you can subscribe for free to receive new issues, keep up to date with the latest news, and more.

Read the article online at:

You might also like


Embed article link: (copy the HTML code below):