Companies looking for an accurate method to gauge how well large batteries and other grid-scale energy storage systems will work are using a new set of evaluation guidelines, called a protocol, that do just that. And now the protocol is being developed into what will become the first-ever standard for measuring and reporting the performance of energy storage systems.
A working group of more than 100 stakeholders representing a wide range of stakeholders worked under the leadership of the US Department of Energy and two of its labs, Pacific Northwest National Laboratory and Sandia National Laboratories, to develop the protocol. The protocol was initially released in October 2012, revised in June 2014 and continues to be improved today.
“Without this protocol, comparing the ability of two different systems to handle the same situation was like comparing apples to oranges,” said Pacific Northwest National Laboratory engineer David Conover, who oversaw the protocol effort for DOE. “Now energy storage systems can be evaluated on a reliable, level playing field.”
The International Electrotechnical Commission and the National Electrical Manufacturers Association are now using the protocol as a starting point to draft the first international and US standards for measuring and reporting energy storage system performance. Developing and approving standards can take several years, but creating the protocol is expected to speed up the process. When adopted, the standards will still be voluntary, though more companies are likely to use them when they have gone through the official standard development process.
In the meanwhile, several companies are already using the protocol when weighing whether or not to invest in an energy storage system. For example, Eos Energy Storage, a developer and manufacturer of grid-scale battery solutions, is using the protocol for in-house testing a demonstrating projects with customers.
“There are numerous use cases for energy storage on the electricity grid and there is a lot of confusion around how to determine best fit technologies for target applications,” said Philippe Bouchard, Eos vice president of business development. “Having a standard testing protocol allows us to characterize performance in a manner that is uniformly accepted by the industry and our customers. This will help to determine the suitability of our product for specific applications and will accelerate market acceptance of new technologies on the grid.”
The protocol is especially important today as more and a greater variety of energy storage systems are being developed to enable the broader use of renewable energy, Conover said.
Updated in June 2014, the protocol now evaluates three energy storage performance uses:
- Peak shaving: storing energy when power is abundant and discharging stored energy during times of high power demand
- Frequency regulation: maintaining the power grid’s frequency at a constant 60 Hertz with frequent energy storage to balance power generation and demand
- Islanded microgrids: small, self-sustaining power grids that generate enough electricity to power a home, neighborhood or town while being disconnected from the larger power grid
The protocol will be updated again this calendar year with three more applications:
- Photovoltaic smoothing: evening out sharp power fluctuations that occur when passing clouds cause short-term changes in solar power generation.
- Renewable firming/load following: making renewable energy more predictable by determining how much power on average can be available over the course of an hour
- Volt/VAR control: keeping power traveling along the power grid within an acceptable voltage range so end users’ electric equipment can operate property and to reduce gradual power loss
More metrics for existing applications will also be added at the request of utilities who are considering using energy storage systems. The protocol will continue to be revised as needed.