This is a regularly updated web resource provided by ESIG to track new installations of GFM projects, efforts to define specifications and testing requirements, modeling and model verification, and definitions of system services that GFM IBRs can provide.

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The majority of inverters today are grid-following (GFL) — they “read” the voltage and frequency of the grid, lock onto that, and inject power aligned with that signal, which comes from synchronous generators. The farther that pockets of wind and solar generation are from synchronous generation, the weaker the grid; the voltage signal is easily perturbed by power injection from wind and solar resources, making it hard for GFL inverters to lock onto it correctly, and this may lead to local instability issues. Inverters with more advanced capabilities, broadly termed “grid forming” (GFM), are needed to maintain stability under higher shares of inverter-based resources (IBRs).

The figure below shows the progression of IBR capabilities needed as shares of IBRs are increasing and grids are becoming weaker over time.

Increasing the numbers of GFM IBRs—battery, wind, and solar plants equipped with advanced inverters—is something of a chicken-and-egg problem. System operators are attempting to determine what capabilities they could or should require of GFM IBRs, while inverter manufacturers do not yet know what capabilities system operators will decide to require and thus what capabilities it makes economic sense for them to develop and offer.

Work to solve this situation is advancing rapidly. ESIG is very active in this area and published a report in March 2022 titled Grid-Forming Technology in Energy Systems Integration, which focused on breaking the chicken-and-egg cycle around the development and deployment of GFM technology. Since the field is developing so rapidly, rather than produce a new report at this time addressing the continued efforts and challenges around GFM deployment, we are providing this regularly updated web resource. Here we track new installations of GFM projects and efforts to define specifications and testing requirements, modeling and model verification, and definitions of system services that GFM IBRs can provide.

Below we summarize recent work on GFM capabilities, with the pages linked above presenting updated information on GFM requirements and other developments around the world.

Grid-Forming Technology in Energy Systems Integration

ESIG Report: Grid-Forming Technology in Energy Systems Integration

In March 2022, ESIG’s High Share of Inverter-Based Generation Task Force published the report Grid-Forming Technology in Energy Systems Integration. The report’s central focus is on breaking the chicken-and-egg cycle around the deployment of GFM technology (Figure 2). System operators are already encountering operational constraints with high shares of IBRs today; however, a lack of understanding of GFM capabilities and commercial availability prevents system operators from requiring GFM capability, either through defining one or more specific grid services to be provided through markets or as an interconnection requirement.

This leads to business-as-usual system planning and operation, along with growing constraints on existing and future IBRs and continued weak grid issues in areas with high shares of IBRs. Within this cycle, battery, solar, and wind developers have little incentive to opt for GFM technology, and manufacturers lack a clear understanding of what capabilities, including provision of new or existing grid services, are needed from future inverters.

 

The report proposes several steps that system operators can take to break this cycle (seen in the figure below). System operators’ steps include:

1. Defining a future target system based on expected load growth, generation expansion, economics, environmental goals, and other parameters
2. Defining resilience parameters — worst-case operating conditions with which the system should be able to cope with no (or limited) impact on serving customer load
3. Determining the technical needs of such target system (e.g., related to voltage and frequency control) based on system studies such as phasor-domain transient simulations, electromagnetic transient simulations, and other analytical methods
4. Formulating technical requirements for system services to serve those needs
5. Quantifying how much of each service is needed
6. Determining the economically optimal form of service provision, whether markets or interconnection requirements
7. Defining technical benchmarking to qualify resources for provision of services, implementing the services, and monitoring performance of the resources providing these services

 

ESIG’s Special Topic Workshop on Grid-Forming IBRs

Following the report’s publication, in June 2022 ESIG held a Special Topic Workshop on Grid-Forming IBRs. The workshop was structured around the steps of solving the chicken-and-egg issue as laid out in Figure 2 above. Presenters included transmission system operators with high shares of IBRs, manufacturers with commercial GFM IBR offerings, and researchers developing grid-forming controls and specifications, and they spoke about concrete steps being undertaken around the broader deployment of GFM technology.

• Batteries were identified as low-hanging fruit, given that they only require control changes to provide core GFM capabilities (excluding high overcurrent capability and black start).
• Presenters discussed how commercial offerings for GFM batteries are already available today from multiple manufacturers. However, in the absence of clear requirements for GFM IBRs’ capabilities, GFM IBRs need to be customized for specific applications, which leads to higher costs.
• Participants recommended distinguishing between equipment specifications or minimum capability requirements, and system needs and system services. Some of the services may need to be provided by all resources (or all new resources) and therefore be included as interconnection requirements, while other services can be procured through the market and provided by a subset of resources that have the necessary capabilities.

ESIG Briefs for Decision-makers

These findings are summarized in two ESIG decision-maker briefs:

• “Benefits of Grid-Forming Energy Storage Resources: A Unique Window of Opportunity in ERCOT”
• “A Unique Window of Opportunity: Capturing the Reliability Benefits of Grid-Forming Batteries”

Regularly Updated Topical Webpages

For the most up-to-date information tracking the progress in deployment of GFM IBRs world-wide, please visit these pages:

Installed and Planned Grid-Forming Projects

This page tracks GFM projects around the world that are in operation or under construction, providing some general information about the projects as well as useful links to further resources.

Grid-Forming Specifications and Testing Requirements

This page tracks GFM specifications and testing requirements that are being developed and published globally by system operators, regulatory bodies, and research organizations. The page will also provide references to publications comparing and commenting on these requirements.

Modeling and Model Verification Efforts [coming soon]

This page tracks the development of standard library models (so-called generic models) for GFM as well as any additional model verification requirements related specifically to GFM technology.

Studies Evaluating Benefits of GFM [coming soon]

This page tracks recent studies evaluating the benefits of GFM resources and/or supplemental devices (such as GFM STATCOM or HVDC converter stations) for high-IBR grid support.