It isn’t news that more American homes, businesses and communities are adopting clean energy technologies – solar, wind, energy storage and electric vehicles – as they recognize the environmental, economic, resiliency and public health benefits.
What we don’t hear much about are the challenges associated with interconnecting these distributed energy resources (DER) with the electric distribution system, while maintaining grid safety and reliability.
Interconnection standards are the ‘rules of the road’ for DERs connecting to the electricity grid, and they have a considerable impact on the overall cost and time to develop projects. As the amount of DERs increases, new technologies and practices are necessary to accommodate them in an efficient manner, while also optimizing their benefits to customers and the grid.
Last year, the Institute of Electrical and Electronics Engineers (IEEE) made significant updates to its national standard for DER interconnection, specifically to enable significantly higher penetrations of distributed energy resources on the grid. Over the next few years, states across the U.S. will have to adopt and implement the IEEE Standard 1547-2018 for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces.
Transforming how DERs function
In a nutshell, this nationally applicable standard, once implemented across states and utilities, will transform how DERs function on the electric distribution system. The 2018 IEEE standard will help ensure new DERs meet the most updated grid performance standards, which will maintain or increase the stability, reliability and intelligence of the distribution grid over time, as more customers choose solar, energy storage and other clean energy technologies.
Compared to its 2003 predecessor, IEEE Standard 1547-2018 requires DERs to be capable of providing specific grid supportive functionalities relating to voltage, frequency, communications and controls. With a variety of options built into the standard, a full understanding of the implications of each element of the rollout will be critical, and it may be more challenging to apply uniformly, with differences potentially based on DER system size, technology or local grid conditions.
While state regulators are tasked with formally adopting the new standard, utilities will need to integrate them into their interconnection protocols. Furthermore, DER industry representatives, technology manufacturers, state and federal agencies, national laboratories and advocates will all be impacted by the implementation of the new standard.
A few states have begun the process
California and Hawaii have already begun deployment of some smart inverter functionality, although work still remains to be done in those states to fully integrate smart inverter capabilities into these markets.
Iowa has just recently begun to investigate what should be done to update their interconnection rules, in light of the IEEE Standard 1547-2018.
Massachusetts, through its long-standing Technical Standards Review Group, is now tackling integration of the new standard into state interconnection procedures. In addition, the Department of Public Utilities just initiated a new inquiry to investigate the interconnection of distributed generation, which aims to review the current standards and procedures by which DG facilities are interconnected to the electric power system (D.P.U 19-55).
Lastly, Minnesota has made considerable strides over the past year to incorporate the IEEE Standard 1547-2018 into the state’s Technical Interconnection and Interoperability Requirements. The Minnesota Public Utility Commission (PUC) made a decision to use the 2018 IEEE standard as the basis for its new set of interconnection rules, putting Minnesota ahead of most other states in terms of its proactive consideration of the standard. Notably, the commission pursued a collaborative stakeholder process that provides a good model for a structured, inclusive rulemaking process, with a specific goal of adopting the new IEEE standard – a valuable approach given its complexity.
In addition to the state’s utilities and commission staff, the state renewable energy industry trade association (Minnesota Solar Energy Industry Association), the leading state clean energy advocacy non-profit (Fresh Energy), and IREC, the national Interstate Renewable Energy Council, have all been working collaboratively over the past year to vet, discuss and draft the new technical requirements. The commission also engaged other experts, including NREL (National Renewable Energy Laboratory) and EPRI (Electric Power Research Institute), as well as the IEEE. The effort is still underway, and the final rules should be complete in 2019.
Although more work remains to implement the standard, Minnesota illustrates a good collaborative model for harmonizing older or new interconnection rules with the IEEE Standard 1547-2018 – something all states working on interconnection should seek to accomplish. Similarly, as states look to update interconnection requirements for distributed solar and wind, it is a great time to consider other updates, specifically for energy storage (or solar+storage).
Navigating technical and policy issues
Earlier this year, IREC published Making the Grid Smarter: State Primer on Adopting the New IEEE Standard 1547-2018 for Distributed Energy Resources. IREC’s new resource will help states, regulators and other stakeholders navigate the related technical and policy issues they will need to address. IREC’s Model Interconnection Procedures are also available, with an update to these procedures forthcoming in 2019.
When the standard is broadly implemented, DERs will have the ability to automatically respond to certain grid conditions. Clearly defining DER settings in statewide interconnection rules will help increase efficiency, minimize confusion and reduce costs.
Specific outcomes of IEEE Standard 1547-2018 implementation include:
- DERs will automatically help to avoid potential negative impacts and ideally, this will enable DER customers and utilities to optimize their grid benefits.
- More DERs will be capable of connecting to the grid under higher penetration scenarios, assuming their control functions are set up adequately to accommodate the grid conditions.
- Customers installing DERs may see shifts in their distributed generation output under certain scenarios, which might require the adoption of new consumer protection measures.
- The interconnection process used for DERs connecting to the grid will need to be updated to reflect the new standard (and to reflect the vastly different conditions under which the grid is operating today, as compared with 2003).
IREC’s President/CEO Larry Sherwood recently added this encouragement for states. “While full rollout of the new standard is not until 2022, states and regulators will benefit from beginning to understand and implement the updated standard now. Even in states where DER penetration is low today, this will help ensure new DERs meet the most updated performance standards, while giving latitude to utilize the enhanced grid functionality as the volume of DERs increases on the grid.”
Writen by Brian Lydic, Chief Regulatory Engineer for the Interstate Renewable Energy Council (IREC)