The use of distributed energy resources (DERs) such as solar photovoltaics (PV), energy storage systems (ESSs), and electric vehicles (EVs) is rapidly expanding. The deployment of these technologies creates new challenges for the electrical distribution system and for customer energy management. One such challenge is effectively communicating with and controlling these devices. To overcome it, we need to implement DERs that are interoperable with the information technology and operational technology (IT/OT) systems of any utility or end user. This interoperability should be so seamless that DERs become plug-and-play technologies. We are a long way from that today.
Proprietary Systems Impede Market Growth
Proprietary implementations of communication protocols have a strong hold on the industry. The first wave of battery energy storage systems featured proprietary software. First movers in the field designed their systems to meet the technical needs of the use case and little more. If a utility had an ESS from one of these first movers, it would need to engage that firm to provide expensive recoding, redesigning, and reengineering of the original system if the use case changed or equipment, such as a power conversion system (PCS), had to be replaced.
If that situation were to continue, users would be faced with the burden of custom, nonrecurring engineering for each DER added to their sites. But proprietary implementations have an additional drawback: they can’t evolve, which limits their future functionality and interoperability. Designed for the specifications of today’s users, closed systems respond to a specific need at a specific point in time. Updating them requires expensive custom work. But our energy market is rapidly changing and will continue to do so. Building a custom system just for today increases risks and adds long-term costs. Instead, users should demand a forward-thinking approach incorporating open standards that can be adjusted in a holistic manner rather than system by system.
Adoption of open communications protocols could accelerate the deployment of DERs and energy storage systems. Most analysts expect both types of assets to grow significantly in the coming years, driven by regulatory support and falling technology costs. Employing open communications protocols could turbocharge that growth by reducing some of the risks and long-term costs of adopting a given technology.
Utilities, major DER prosumers, and the energy storage supply chain all have important roles in promoting interoperability, thereby enabling the next wave of growth. The industry must focus on engineering energy storage for adoption at scale—including the creation and support of software open standards—to drive down costs and to limit technology and supplier risk for utilities and prosumers. These behind-the-meter DER prosumers are particularly attuned to the value of installing an interoperable system so that they can share in the available incentives and value of providing grid services.
All images: Austin Energy
Open Standards and Standardization
For the energy storage supply chain to create energy storage and DERs for adoption at scale, it must embrace two key elements: open standards and standardization. First, there needs to be a deliberate, industrywide focus on identifying innovation zones where rapid performance gains are both desirable and possible. It is within these zones that new capabilities will significantly improve performance and make the overall product more valuable to owners. Second, unwavering attention must be paid to consistency and stability, which will drive volume, reduce costs, manage risk, and improve safety. One of the best ways to achieve that outcome is to drive toward standardization.
Publicly available, consensus-based, standardized interfaces ensure that technological advances added in innovation zones can be incorporated into existing systems at a reasonable cost. This architecture also ensures that utilities and DER prosumers can select new components created as innovation drives further progress—without having to redesign their entire system.
Software open standards are specifications that define how information is stored or communicated between different software programs running as part of a larger system. The “open” part refers to the fact that the specifications are available free of charge to any interested party and participation in the development of those standards is open to anyone willing to meet the conditions set by the governing group. The “standards” part refers to the fact that the specifications are developed and refined through a process that involves a wide variety of participants (including utilities, in some cases). These participants then commit to requiring or requesting those standards for procurements as project owners or implementing the standards in their own products as suppliers.
Industry Collaboration on Standards
One industry collaborative that is developing open standards specifically focused on energy storage is Modular Energy Storage Alliance (MESA). MESA is currently working on two specifications: MESA-ESS and MESA-Device/SunSpec Energy Storage Model. MESA-ESS provides a standard framework for utility-scale ESS data exchanges. The draft specification addresses ESS configuration management, ESS operational states, and the applicable ESS functions from the IEEE 1815™ (DNP3) profile for advanced DER functions. The MESA-Device Specifications/SunSpec Energy Storage Model addresses how energy storage components within an energy storage system communicate with each other and other operational components. MESA-Device Specifications are built on the Modbus protocol.
A more conventional standards organization, the Institute of Electrical and Electronics Engineers (IEEE) publishes the IEEE 1547 series of standards that have helped shape the way utilities and other businesses have worked together to interconnect increasing amounts of DER with the distribution grid. Although IEEE standards are not truly “open” (they can be purchased for a small fee), IEEE excels at industry collaboration by including both end users (utilities) and equipment vendors.
IEEE 1547 focuses on the technical specifications and testing of DERs for interconnection and interoperability while remaining technology neutral. The standard provides requirements relevant to the performance, operation, testing, safety considerations, and maintenance of the interconnection. It includes general requirements, responses to abnormal conditions, power quality, islanding, and test specifications and requirements for design, production, installation evaluation, commissioning, and periodic tests.
The IEEE 2030 series of standards has also been recently updated and is helping to support greater implementation of communications and information technologies providing interoperability solutions for enhanced integration of DER and loads with the grid. All DERs interconnecting in California under its Rule 21 are required to be using standardized communication protocols (see www.cpuc.ca.gov/Rule21), notably IEEE 2030.5™, by August 22, 2019. Such California mandates typically lead to wider adoption in the U.S. Another example is the development of Underwriters Laboratories (UL) standard 1741 SA to address performance requirements for California Rule 21.
Standards and Interoperability in Action
The work of these organizations to promote standards and interoperability is beginning to bear fruit. Progressive states, utilities, end users, and vendors of DER technologies are putting the technology to use in the field—in both front-of-the-meter and behind-the-meter systems.
In front of the meter, the Los Angeles Department of Water and Power (LADWP) is leading a vanguard of publicly owned utilities looking to embed open standards and interoperability principles in their energy storage programs from conception. LADWP commissioned its first 20-MW lithium-ion battery energy storage system adjacent to 570 MW of existing solar generation in the Mojave Desert. This battery system is connected to LADWP’s 230-kV transmission lines through the new Beacon Collector Station and the Barren Ridge Switching Station. This system provides frequency control, voltage support, and power smoothing to assist LADWP in complying with its NERC/FERC Balancing Authority requirements, as well as its transmission grid and line stability responsibilities. These grid services benefit all solar PV connected to the Barren Ridge Switching Station as well as 135 MW of wind farms in Kern County.
Doosan GridTech was hired by LADWP to design and install this system. It was critical for the storage system to be interoperable with LADWP’s systems well into the future so that resources could be added to the site on a plug-and-play basis. Doosan’s MESA-compliant design met this two-fold objective. The use of MESA-ESS as the standard for SCADA communication means LADWP can securely communicate and control the system from its central control room. In addition, the use of the MESA-Device Modbus standard means the system can be expanded to as much as 100 MW without any additional control software or nonrecurring engineering communication integration.
Another example of interoperability in the field is the Austin SHINES project with Austin Energy. Austin Energy is using Doosan GridTech’s distributed energy resource management system to schedule and dispatch a variety of front-of-the-meter and behind-the-meter assets. Its utility-scale storage systems leverage MESA standards just like the Beacon system at LADWP. SunSpec solar power standards are used to change the setpoints for residential solar smart inverters for voltage support applications. OpenADR demand response specifications are being implemented to dispatch both residential and commercial energy storage systems to lower energy costs for Austin Energy from ERCOT. Having built these open-standard layers into its DER program at this early stage, Austin Energy now has a platform that can integrate and reliably dispatch new devices as they are installed in the future.
Standards and Interoperability Can Lower Costs, Increase Deployments
Whether in front of the meter or behind it, embracing standards and interoperability is key to driving down costs and managing the risks of DER proliferation. By doing this, the flexible, low-carbon grid of the future will become a reality sooner than we think.