Using advanced inverter tech to deliver power system stability

Doris Spielthenner of SMA Australia writes how, as the continued influx of renewable energy raises questions about maintaining power system stability, multi-functional advanced inverter tech will prove a pivotal solution.

The future of energy is renewable, and that future is rapidly approaching as countries around the world commit to varying zero-emissions targets.

As we continue down the path of replacing fossil fuels with renewable energy coupled with inverter-based resources, we must ask a crucial question: how can we maintain the stability, resilience and affordability of power systems while integrating a range of renewable energy sources?

The answer: multi-functional advanced inverter technology. This innovation plays a pivotal role in our journey to creating renewable energy dominated power systems, allowing us to generate clean, emissions-free energy while improving system stability.

The evolution of inverter technology

Inverter technology has a long trajectory which has allowed for continual innovations to inverter capabilities leading to current grid-forming functionalities that have revolutionised the role of inverters in our power systems in recent years. These advanced inverter technologies meet the demands and expectations of our changing energy systems, ensuring their ability to become the primary source of reliability in energy supply.

In the 90s, inverters had no capacity for grid support, meaning they did not play a role in maintaining grid stability. By the early 2000s, the introduction of grid-supporting functionalities played a crucial role in advancing renewable energy. In the 2020s inverter-based resources have reached high enough penetration that providing energy alone is no longer enough: it has become essential for inverter-based resources to become active grid managers.

Grid forming technology provides a source of grid stability to Transmission and Distribution Network Service Providers (collectively NSPs). This technology opens new market opportunities by delivering grid-forming services to NSPs, whose demand will only continue to increase as power systems around the world grow their share of renewable energy.

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The evolution of grid-forming technology has emerged as a key player in the sector, putting inverters at the forefront of ensuring stability and system strength. Battery energy storage systems (BESSs), enabled by grid-forming inverters, can meet the growing stability needs for power networks, offering a game-changing solution for grid stability and safety while providing BESS operators with multi-use opportunities and stacked revenue streams through energy arbitrage and participation in ancillary markets.

These advanced inverters are voltage-controlled devices that provide functionality equivalent to synchronous generators, autonomously managing power frequency and delivering key services to minimize the risk of power outages or blackouts. Their instantaneous inherent response to network events, rather than relying on control systems with time delays, enables inverters to become a primary source of system stability, making them crucial in maintaining the integrity of modern power grids.

While some may question the capabilities of these new technologies, battery storage with advanced inverters is far more capable than traditional synchronous power plants when it comes to efficiency and response time. This stability and versatility are a testament to the power of battery energy storage systems and the reason why grid-forming solutions are paving the way for a more stable and sustainable energy sector.

Advanced inverters also have the ability to restart a grid – also known as ‘blackstart’ – in the event of a power failure; restarting is an essential function required by any power system.

Advanced inverter technology’s ability to deliver grid services has already been proven in real power systems. During severe grid disturbances in Odessa, Texas in 2021 and 2022, the use of advanced inverters was crucial to maintaining an ongoing power supply for the region. Here in Australia, advanced inverters were instrumental in maintaining stability in weak parts of the network such as in the West Murray region in Victoria and New South Wales.

By reducing the need for network reinforcement and re-dispatch measures, advanced inverter resources make it possible to maintain stable grids powered entirely by clean energy. As we create a world powered by clean energy, advanced technology is crucial to creating a dependable and affordable system to power our homes and businesses.

The future of renewable energy

Envisioning a world powered by renewable energy sources begs the question: if we cannot predict or control the short-term fluctuations of wind and solar, what happens when demand for renewable energy exceeds supply?

The answer lies in energy storage systems’ ability to store energy when generation exceeds demand so it can be released during periods when demand is higher than generation.

By adequately designing energy storage systems accounting for generation and consumption profiles we can virtually eliminate the likelihood of demand outstripping supply and, by extension, the risk of power outages caused by an overwhelmed grid.

The inherent flexibility and opportunity provided by grid-forming inverters is invaluable to the future of renewable energy. Not only does it protect our communities and industries from power interruptions, but it benefits both consumers and industry by making the entire system far more efficient and affordable to maintain. It is only through advanced inverter technology that we can pave the way to large-scale adoption of stable, affordable, and sustainable energy.

In fact, BESSs are so crucial to the future of a stable and resilient renewable energy sector that the Australian Renewable Energy Agency (ARENA) has provided funding to support grid-connected BESS projects with grid-forming capabilities. This expansion of these innovative technologies is pivotal to creating cleaner, more sustainable energy systems that can respond to grid-events with little to no delay or disruption to supply.

The renewable energy sector is pivotal to creating a more sustainable world, but it must not come at the expense of grid stability. With advanced inverters at the forefront of renewable energy innovation, we have the power to pave the way to a greener, more resilient energy landscape.

About the author

As managing director of SMA Australia and Regional Manager APAC, Doris Spielthenner heads the Residential, C&I and Large Scale Utility business across ANZ, India, China and Taiwan, South East Asia, Japan and South Korea.