Inertia is the energy stored in a large rotating mass like a generator or some industrial motors. Historically, the power system relied on the inertia inherent in large, centralized generation plants to keep it stable. Inertia acts rather like a car’s shock absorbers that smooths the shock over bumps in the road.
Renewable energy generation reduces the impacts of climate change and is essential to NGESO’s goal of operating a zero-carbon electricity grid by 2025. However, the replacement of large fossil-fueled generation with wind and solar removes much needed inertia that has to be dealt with. In addition to the increasing connection of renewable energy, utilities are also experiencing a growing trend for the large numbers of electric motors in industry and commerce that operate with variable speed drives. While this is an important contribution to energy efficiency, it also results in a further loss of system inertia. These factors have contributed to NGESO reporting an historic and anticipated fall in system inertia.
Providing Stability Services
Greener Grid Parks
The Lister Drive Greener Grid Park project will provide services including inertia, voltage control and short circuit current, which provide system strength. The site was selected due to its location near to an existing substation that enables the two condensers to connect to the system at the transmission voltage (in this case, 275kV).
Fifty years or so ago, synchronous condensers were common in the power industry but in recent years they have become much less common. This is because their former prime function, dynamic reactive power compensation, can be handled by modern power electronics equipment. However, the system stabilization issues discussed are driving the return to rotating devices with physical inertia that replicates the operation of large generating plant.
Capacity and Construction
To ensure round-the-clock availability for this vital system, Statkraft has signed a 10-year services contract with ABB’s UK field service team to provide a full range of maintenance services, both planned and quick response. Digital condition monitoring solutions will be deployed to optimize performance and predict maintenance needs. By assessing real-time data with cloud-based analysis, the team will be able to plan corrective actions before issues occur, ensuring system reliability.