Interview: Building the new generation of battery-based power stations

Interviews | December 21, 2016

By Rich Pell

Jayesh Goyal, chief commercial officer of Younicos

Last week Younicos announced it is working with Centrica in the UK to build one of the world’s largest battery storage plants. The 49MW plant will supply homes around the Barrow area of Cumberland from a custom-built plant.

“We started in Germany ten years ago by people that came from the PV (photovoltaic) solar world [Solon],” said Jayesh Goyal, chief commercial officer at Younicos (left). “As you integrated more renewables into the grid they saw you would need more battery storage in the grid, so they developed software to enable a series of different grid services using different battery systems.”

In 2014 the company acquired startup Xtreme Power in the US, opening up the North American market. Xtreme was building 12 systems around the world with over 60MW of power at the time, using its own lead acid battery technology. The combined company now has 150MW of battery plant installed, demonstrating how far the industry has moved in just two years, with lead acid replaced by lithium ion and the size of projects increasing ten fold.

Younicos sees integration and software as the key driver, deliberately working with battery makers, local power operators and construction firms rather than doing everything itself.

“Right now we are one of the largest energy storage integrators, selecting which batteries, which inverters are needed – that’s the core of what we do,” said Goyal. “We try to focus on a range of services – voltage control, frequency regulation, black start, peak shaving, so our software manages that.”

“We do not see ourselves as being in the battery manufacturing or developing our own inverter – companies that have expertise in these areas we want to use the best technologies for different applications,” he said. “What we like to do is if we take an inverter we want to integrate it more tightly with our software.”

For example if an off -the-shelf inverter has a response time of 100ms we would work with the manufacturer’s software team at the firmware level to get say 30ms. We would rather do that than develop our own inverter as that includes global networks of spares and support and that’s quite challenging. Even on the full turnkey delivery of a system we are not the experts on construction at a local site so we partner with the local power companies. For example the 49MW we are constructing a building rather than a whole bunch of containers on the ground.”

The size of the plant is a result of regulations, he says. “There are regulations in the UK that mean that the moment you cross 50MW it’s a different regulatory environment. That’s why everyone in the UK tries to stay below the 50MW threshold.”

While the current focus is on large battery systems, Youanics sees potential in the ‘virtual power station’ that brings together many different battery storage units often in commercial and industrial (C&I) applications..

“If you think about microgrid and islands we are able to integrate different types of energy resources and manage it as a microgrid with its own battery. The other things that is interesting is that if you have several small battery systems at different sites, as we monitor all these systems, we can integrate these different resources and manage them as one unit – we can treat them as an aggregate and that’s a valuable service if a customer has multiple sites, or even across multiple customers,” he said.

At the smaller end the Ycubed system (right) is like a container but optimised for thermal management and heatflow within the systems. “We figured out the most flexible configuration for the different battery types so everything is integrated in the 5 to 10MWh range – once you get larger than that a building is a better solution.” Photovoltaic power suppliers are also looking at adding storage to provide a more consistent service, which will start driving demand for 100 to 200MWh systems, he says.

Younicos tests out different battery technologies at its lab in Berlin, and has seen lead acid fade away as a technology in favour of lithium ion. “The reason we focus on Li ion is because of the energy density and it is the most proven solution right now as the costs have been coming down dramatically. We are able to work with multiple battery chemistries so we have tested out other batteries.”

“Flow batteries are pretty good for long duration for applications such as a photovoltaics plant that wants six hours of storage and we have tested those but they have not yet reached the same level of maturity,” he said.

Goyal cannot see anything to slow down the roll out of such systems as regulations are opening up to allow more battery storage.

“If you look at all the projections they are expecting all of this to grow and the regulations are enabling more of these storage systems with system operators being required to add storage,” he said. “As the battery prices are coming down you see more C&I applications. In some areas where the demand charges are coming down that can reduce the business case but by and large regulations are favourable,” he said.

www.younicos.com