May 16, 2019: Solar power plant and battery storage system group of companies Upside Group fired up its second lead carbon energy storage system in Germany on May 3, expanding its battery portfolio to 40MW.
The 25MW system, the second of five planned, will deliver primary control reserve grid services — balancing frequency and capacity changes automatically — using advanced lead carbon technology.
In a move that bucks the trend the firm uses lead acid as the storage medium, rather than lithium ion, because the technology offers the economy and safety of lead acid with the low maintenance requirements of lithium cells, said Upside managing director, Marc Reimer.
“The lower energy density compared to lithium cells is not a disadvantage in stationary storage systems. Most lead carbon battery cells are dry accumulators, and the electrolyte is bound in a glass fibre fleece and there are no internal liquids.
“Although these cells must also be equipped with a one-way valve for possible outgassing (in the event of over charging), they can be tilted or even flooded without any problems, without the possibility of substances such as sulfuric acid escaping.”
The system in Bennewitz, a Saxony municipality, is able to stabilize the grid 24/7 in a power climate that is seeing grid frequency being adjusted several hundred thousand times a year to cope with an intermittent power supply, the Germany firm said.
The ESS was successfully dispatched in January, ahead of its official commissioning, to prevent a major blackout due to a significant drop in Germany’s grid frequency to below 50 Hz.
Reimer said grid frequency must always be readjusted externally due to volatile generation and consumption.
He said: “Batteries can do this much better than other technologies. As well as unbeatably fast response times, it is also much easier for the battery to provide control power, because there is no need to generate electricity first, but excess electricity is stored temporarily if the frequency is too high.
“If the frequency is too low, this electricity is returned to the grid. The battery is always half charged and reacts in the required direction, fully automatically, 365 days a year.”
Bennewitz is the second joint project between Upside and SMA Sunbelt Energy. The other in the Leipzig area of Germany was inaugurated last September 14, once again using cells manufactured by Chinese firm Narada. Read that story here.