From Slovakia to China: Energy storage is taking off

2013-04-24 - Stability of the grid has a special meaning in the renewable power generation sector. Storing energy from the grid and feeding it back when required offers a range of options that enhance the stability, performance, power quality and reliability of electricity grids integrating renewable sources. ABB and Prudent Energy have numerous references in this application field and their number keeps growing.

Microgrid application in Slovakia
To maintain efficient transmission and distribution, the active and reactive power balance in a power system needs to be controlled. Inadequate active and reactive power management can result in high network losses, equipment overloading, unacceptable voltage levels, voltage instability and even outages. For a pioneering microgrid customer in Slovakia, ABB and Prudent Energy have provided a turnkey solution that integrates the utility with the microgrid, providing a more efficient renewable energy supply.
The solution incorporates ABB’s 100 kW PCS100 ESS, Programmable Logic Controller (PLC) system, transformer and circuit breaker with Prudent Energy’s specialized and patented Vanadium Redox Battery (VRB) energy storage system. Prudent’s technology integrates smoothly with ABB’s PCS100 ESS: it charges the VRB battery and regulates the power flow by discharging power to the grid when wind and solar energy output varies or during unstable events, such as extreme weather conditions.
For this project ABB’s power protection team in China provided a new solution for Prudent’s VRB battery: it is smaller in size, lower cost and easier to operate.

Jeju island installation, South Korea
A few years ago, South Korea established a suite of incentive and support programs to encourage a shift towards a more sustainable energy generation base. The local government of the Jeju Island, the biggest island in Korea, is keen to increase the share of renewables in the island's power generation spectrum. Multiple wind and solar installations are underway or are already in operation there. The main goal is to create an infrastructure that can provide the island with reliable power, even with the HVDC link to the mainland disconnected. However, the higher the portion of renewables, the more vital grid stabilization and energy smoothing aspects become. This is where energy storage system comes into play.
ABB's PCS100 ESS converter technology is able to establish a grid on its own, allowing renewable energy source to connect to the grid. In this sense PCS100 ESS is similar to a synchronous generator, but more flexible in operation and faster in response to grid instability. It supports the voltage even if the grid power is off and has "black start" capability (i.e. the system can be started without the grid, purely from the battery).
A small demonstration and test system, featuring PCS100 ESS and VRB battery system supplied by ABB and Prudent Energy, was installed in the island’s laboratory to investigate the best power system topology and control strategies. The 100 kW solution demonstrated stable operation, storing and releasing energy according to the requirements of the grid.

"Golden sun" demonstration project in China
China’s energy demand is growing rapidly and the renewable sources play an important role in the country’s new energy strategy. To gain more knowledge and test the available technology in certain areas, China State Grid (SGCC) initiated the roll out of the “Golden sun" demonstration project in Zhangbai county, Hebai province. The project involves 100 MW wind power, 50 MW solar power and 20 MW energy storage systems, split into smaller batches and supplied by different manufacturers, featuring various technologies. Thus, SGCC can evaluate and benchmark different concepts and test system performance in different applications.

For this project ABB and Prudent Energy delivered a 2 MW energy storage system based on VRB battery and PCS100 ESS power converter technology, integrated with PLC, transformer and switchgear. The system will be used for multiple tasks, for example smoothing the renewable energy output, peak shaving and frequency regulation. As Prudent Energy’s VRB can offer a power supply over many hours, it is perfectly suited for smoothing or shifting renewable power generation output.

About the collaboration
Prudent Energy is the designer, manufacturer and integrator of the patented Vanadium Redox Battery (VRB) energy storage system – a long-life, environmentally friendly “flow battery” system. Founded in 2007, the Prudent Energy group of companies maintains corporate offices in Washington DC (USA) and Beijing (P.R. of China), with research, development and assembly facilities in the United States, Canada and Asia.
ABB and Prudent Energy have worked closely together to design the above described grid stabilization technology.