Bigger, faster BESS: Wärtsilä’s EMS for the ‘multi-gigawatt-hour’ era of energy storage

That’s a silly question, of course; there are plenty of components without which an energy storage asset, whether batteries, batteries in hybrid with generation, or using non-battery technology, can’t function.

But if you asked energy storage technology providers what the most overlooked component is in terms of its importance, the energy management system (EMS) might be a common response.

The EMS, sometimes also called the power plant controller (PPC), is essentially the software-based operating system and controls platform which simultaneously monitors, coordinates and optimises the asset during its lifetime.

Wärtsilä Energy Storage & Optimisation (Wärtsilä ES&O) has been in the game longer than most. Its GEMS Digital Energy Platform was originally developed by Silicon Valley energy storage startup Greensmith Energy back in the 2010s before Wärtsilä ES&O acquired the software-specialised system integrator and launched its own energy storage business.

Wärtsilä’s GEMS suite is now on its seventh iteration, as reported earlier this week by Energy-Storage.news as the platform was launched.

Its new features and updates are designed to enable effective control and dispatch in an industry of ever-larger battery energy storage system (BESS) projects, “multi-gigawatt-hour” projects in fact, while helping respond even faster to grid signals.

Combined value

A lot of the value that comes from energy storage is driven by the software and the EMS, says Wärtsilä ES&O’s head of software product management, Ruchira Shah.

“Storage, unlike a solar or wind plant or gas plant, doesn’t have intrinsic value in the same way, because it’s not a generator of energy. It is, at its heart, an arbitrage device, which means that it really matters when you charge and when you discharge and how you make those decisions,” Shah says.

“That’s all software.”

For example, the EMS can be the difference between responding in time to meet market requirements and not; a good EMS can “easily enable” operators to adapt to changing grid codes or when new market opportunities open up.

That doesn’t just apply to standalone energy storage projects; GEMS is an EMS from which any type of energy asset can be controlled, including the gas-fired engine power plants which Wärtsilä’s legacy business divisions manufacture and sell around the world.

It can also mean the coordinated control of, say, solar and energy storage within the same portfolio, or even the same power plant or microgrid. That, again can mean economic value as well as operational efficiency, and in the case of renewables, making low-carbon energy dispatchable.

“Solar is not a schedulable asset, it’s going to produce when it produces, and as an operator you can curtail it, but you can’t make it produce more,” Shah says.

“The interesting thing is that when you combine different assets, like when you combine solar and storage, all of a sudden you can now support, say, a power purchase agreement (PPA) requirement that is looking for firm output in, say, a specific time period that with solar alone, you can’t meet.”

“We support a range of different asset classes, including solar, wind, storage and engine power plants and then we support a range of different markets. I think the challenge for any software player is to be able to understand how those asset classes intersect with that market and also what opportunities you can have when you combine different assets.”

Multi-GWh scale projects

In a 2022 interview with this site, Wärtsilä ES&O head Andy Tang spoke about how average customer product sizes had moved from single-digit megawatt-hours of capacity to double digits and were already at around 100MW/200MWh.

This had been especially true in the US and Australia, two of the markets where the company is most active. Since that interview, the trend has continued, to the point that the GEMS 7 platform is designed to be suitable for projects that go into the multiple gigawatt-hour scale.

“Things are moving so fast in the industry that it’s tough to predict with certainty what projects are going look like in two to three years,” Shah says, but in the case of the rapid evolution of project sizes, the message from customers and the market was clear.

“This was a little bit easier, in the sense that we could see larger projects in our pipeline, and it takes a while for these projects to reach the contract stage, then once they’ve reached the contract stage, there’s often a couple of years before they actually commission them,” Shah says.

“There’s a fairly long lead time. So, in this case, it was a lot clearer where we had to go to. Looking at the pipeline, you had a sense that this is where we need the software to go in the future.”

From a technical perspective, delivering an EMS fit for very large projects is all about the “huge volume” of data that needs to be collected and actioned upon, Shah says, with data coming from metering systems, inverters and power conversion system (PCS) hardware, and of batteries, down to the module level.

That meant designing software and an architecture that could support that volume of data. At the same time, the new platform comes with new visualisations for large sites on the monitoring portal.

It enables users to “zoom out and see a full picture of the site, and then be able to zoom in to particular sections of the site within the user interface (UI),” Shah says.

Market needs faster response times

Wärtsilä claimed GEMS 7 comes with a number of other new enhancements, from upgrades to alarm and monitoring systems to features that enable automated cell balancing and state of charge (SoC) calibration.

Alongside those, the EMS is also designed to offer lower latency in responding to grid signals, in other words boosting an already split-second response times, which Ruchira Shah says is going to be vital for asset owners looking to participate in increasingly sophisticated classes of ancillary and system stability services applications.

There is generally in the global market a move towards faster response times and decreased latency, Shah says.

She offers the example of Australia’s National Electricity Market (NEM), where 60-second and 5-minute markets are now joined by the 2-second very fast frequency response (FFR) Frequency Control Ancillary Services (FCAS) markets and associated revenue streams.

“As you increase the number of renewables on the grid, and you decrease the number of spinning turbines which provide natural inertia to the grid, you need to replace that somehow,” Shah says.

“You need to be able to have batteries respond to frequency events faster and faster, and so I think that is why globally we’re seeing requests for shorter response times and markets created for assets that can respond faster and faster to the needs of the grid.

So that’s an important piece, a huge part of the core of GEMS, to be able to meet these new market needs and to be able to meet these new types of requirements in terms of reduced latency.”