The benefits of grid connected storage
The technology can provide a strategic reserve and reduce the risk of blackouts
On Wednesday February 11, 2015 just after 23:30, Al Omaria 400kV substation experienced a trip which disconnected approximately 2,000MW - roughly 40% of its actual power generation capacity at that moment - from the Kuwaiti grid.
The Ministry of Electricity and Water (MEW) couldn’t save the grid despite maintaining a very high share of spinning reserve. The frequency dropped as low as 46 Hz and Kuwait experienced a blackout that lasted a couple of hours. While MEW officials still debate the root cause of the incident, one has to pose the question - what could have been done to avoid a black out in such circumstances?
No conventional gas or steam turbine technology can respond fast enough to achieve the frequency support the Kuwait grid would have needed at that moment to save the day. It would probably have required a strategic reserve in the range of around 800MW with a response time of less than 30ms to buy enough time for the grid operator to react and for conventional power generation assets to sufficiently ramp up.
Large scale, fast responding strategic power reserve connected to the grid may still sound a bit utopic to most T&D Engineers, but the technology has been available for some time. During the last seven years a number of battery based power storage systems in the MW-range have been installed and successfully tested in the US, Europe, China and Japan and the technology is ready for large scale deployment.
In particular, Lithium Ion battery technology is benefitting from large investments made bythe car industry in R&D for electric vehicles. As a result the industry now has access to a high performing battery cell technology that is at the heart of power storage systems that can deliver a strategic reserve of up to 32MW in less than 30ms, such as the one installed in 2009 by NEC Energy Solutions at their Los Andes project in Chile.
To achieve the grid connected battery based strategic reservethat MEW in Kuwait would have needed that day in February, the power storage industry has to scale up its technology and reduce the cost. The modular and containerized solutions most power and energy storage technology providers offer today are perfectly suited for upscaling, which leaves us with the cost factor.
Tony Seba, who teaches Disruptive and Clean Energy at Stanford University, has estimated that battery based energy storage has achieved an annual cost reduction of 15% over the last couple of years. He further predicts that the combination of PV and battery storage will achieve combined grid parity in the United States in less than three years from now. Even though storage applications where the energy is released more gradually are more cost effective than battery storage systems designed for power applications, the overall developments in terms of cost and installed capacity for power applications are very promising.
Grid connected power storage systems can be deployed to provide a strategic reserve, frequency support and to strengthen the grid at critical locations – all services that allow the utility to operate more efficiently. And the good news is that power/energy storage systems don’t have to be deployed as large centralised systems. It is far more effective to deploy power and energy storage in 0.5 to 40MW systems distributed at various key locations and at different levels of the grid. The fact is that every MW of installed Strategic Power Reserve is making the grid more resilient and reducing the risk of blackouts.