Concerns continue to grow as to how our networks can address the power supply capacity, stability and resilience issues vital to ensure ‘business as usual’ for customers. The result is an increasing interest for grid-connected microgrids, according to David Hughes, ABB Power Grid’s UK managing director.
He explains that microgrids typically integrate renewable energy sources such as solar, wind power, biomass, small hydro, geothermal, waste-to-energy, and combined heat and power (CHP) systems. Increasingly, they are equipped with energy storage systems, including flywheels or lithium-ion batteries.
The heart of the microgrid is the controller, its software intelligence, that orchestrates these diverse resources, managing them to optimise the use of renewables while maintaining grid frequency, voltage and stability. This controller also manages the interface with the main grid, enabling the microgrid to connect and disconnect as required for seamless ‘islanded operation’.
It is this islanding capacity that is crucial for hospitals, factories and data centres. Normally, they will take their power from the main utility grid. But if there is any disturbance in this grid they can simply disconnect and rely on resources within their own microgrid to maintain continuity of power almost indefinitely.
Microgrids are also being driven by utilities interested in their capability to improve reliability by isolating critical pockets of generation and load. If there is a disturbance the ‘embedded utility microgrid’ within the pocket will be islanded to prevent any risk of an outage. Furthermore, the microgrid can feed power back to the main grid to support its stable operation as well as helping with restoration after a major blackout.
Microgrids offer an innovative highly flexible, modular and scalable solution to help support continuity of supply, and ABB is already demonstrating its capabilities in over 30 microgrids deployed worldwide. Even in advanced economies like the UK, they can increase the reliability and quality of power supply; reduce energy costs and enhance their predictability; and reduce carbon footprint and overall environmental impact.
A recent report by the Carbon Trust and Imperial College concluded that the UK could save £17 to 40 billion across the electricity system from now to 2050 by deploying flexibility technologies such as microgrids. Hughes believes that microgrids are clearly building momentum.