Breakthrough 'green' energy storage debuts

As an emerging energy storage solution, the country's new type of water-based battery technology was first applied on March 26 in the eastern province of Jiangsu to boost fast green power charging and discharging.

By partnering with two other forms of energy storage devices (lithium batteries and sodium batteries), the new water-based metal batteries have been installed in a microgrid inside the Wujin National Hi-tech Industrial Zone in Wujin district under the prefecture-level city of Changzhou.

The zone has set up an innovation industrial park to bolster innovation, while the microgrid was jointly launched by Changzhou Binhu Construction and Development Group Co Ltd and State Grid Changzhou Power Supply Co, becoming the largest industrial-park microgrid in Jiangsu to boost large-scale application of new energy in industrial parks.

"With a supply area of 370,000 square meters, the microgrid has 1.61 megawatts of distributed photovoltaics as well as 6,035 kilowatts/10,660 kilowatt-hours of energy storage, providing stable and reliable green power for high-rises, factories and electric vehicles," said Chen Liang, general manager of State Grid Wujin.

A microgrid refers to a small power system composed of distributed power sources (such as photovoltaic and wind power), energy storage devices, local power loads, and energy management systems. It can join a large power grid or operate independently as an island mode.

It has been learned that lithium batteries have high energy density and can store more electricity in the same volume, while sodium batteries can support fast charging and discharging. "But water-based metal battery has outstanding environmental and safety advantages," he said.

Sun Jinpeng, a technical expert at Yixin Energy Technology (Jiangsu) Co Ltd, which is dedicated to water-based metal battery technology development, said the park is being furnished with a new 150 kWh water-based metal battery.

"This is the first time that this technology has been applied in China, showcasing a comprehensive use of various energy storage technologies, and truly achieving' sufficient power and fast charging and discharging'," he said.

In terms of energy collaboration, Chen said the project has created a control platform to serve as a "smart brain" of the park, realizing better regulation of such resources as photovoltaics, energy storage, charging facilities and air conditioning.

As the number of NEVs in the park has exceeded 200, there is a good potential for vehicle-network interaction, Chen added, noting that four interaction points have been built, with 16 7-kW V2G(vehicle to grid) charging stations and two 60-kW special vehicle V2G charging stations.

As intelligent technology has been applied, a car owner can participate in the interaction by completing an authorization on the park's control platform, and plug in the V2G charging station after each parking, Chen said.

"When the power grid needs it, the system can automatically start reverse discharge, and car owners can receive corresponding discharge benefits in real time," he said.

In terms of direct current demonstration, an integrated DC microgrid system incorporating photovoltaic, storage and charging has been built on the southeastern side of the park, integrating a 64.4 kW distributed photovoltaic carport, 2,580 kWh energy storage equipment, and 13 DC charging piles with a total maximum output power of 2,200 kW, he said.