From Hawaii to New York, utilities are connecting renewable, intermittent resources to their grids in unprecedented numbers.
Requests to interconnect customer-owned generation—mostly rooftop solar systems—often start like a soft breeze that is barely noticeable, but then like a storm moving in, the number of requests grows quickly to a gale-force wind that impacts almost every aspect of utility operations.
And for utilities, it is a bit like preparing for a hurricane; they know it is coming, so they are preparing their systems to mitigate potential impacts and watching the weather forecasts.
Exponential growth in interconnection requests is one of the many things utilities are leaning about integrating intermittent resources into their distribution grids. It is one of the many insights the Department of Energy captured in a new guide called Voices of Experience: Integrating Intermittent Resources.
The guide is the result of a working group assembled by the Advanced Grid Research division of DOE’s Office of Electricity Delivery and Energy Reliability. The working group participated in a series of topic-based discussions and regional meetings where the utilities at the forefront of this transition shared insights into the challenges, solutions, and lessons learned from integrating high penetrations of variable generation.
The goal of the guide is to provide information that might not be accessible elsewhere—the kind you might get from talking to a colleague at a neighboring utility.
These are the key themes that emerged from the working group discussions:
Customer engagement has new import
Many utilities are seeing an increase in customers interested in owning their own generation for a variety of reasons whether it be environmental, economic, or self sufficiency”
These customers require—and expect—a new level of information and engagement from their utility. They want responsive, informed customer service professionals who take the time to answer their questions. They are used to having services and information at their fingertips - think Amazon and smartphones - and often request detailed data beyond the utilities current capabilities. They expect the utility to operate with speed and agility—especially when processing their interconnection applications.
Engineers and others are working the challenges
Both the design and operations of the grid are changing. Understanding these changes and developing staff, capabilities, tools, and processes to operate safely and reliably in this new environment takes times. Learning how to operate with high penetrations of distributed, intermittent resources requires testing new technology, determining the value of these resources, and understanding the impact on the existing systems.
Policy and societal preferences are ahead of technology
Penetration rates are often catalyzed by policies designed to support renewable energy goals without considering the impact on the distribution system or the nature of some of the technology. Utilities and researchers are just beginning to understand what is necessary to operate safely and reliably with variable resources and to develop the data, tools, and technology they will need to do so such as precise hourly weather data, sophisticated models, advanced inverters and other devices to round out their toolkit.
Visibility, predictability, and control are key
When penetrations of customer-owned systems are low, the fact that utilities do not have visibility of the customer’s system is less of an issue. But as penetrations grow, the ability to see, control, and predict the output from distributed resources, and the aggregate behavior at the distribution circuit level becomes increasingly important. Computer models of a system will tell operators what they should see, but without monitoring, utilities will not be able to see the actual impacts on system performance. Advanced automation and supporting systems enable operators to ensure safety and reliability while facilitating increased integration of distributed energy resources.
Each situation is unique
All distribution systems were “custom built” over time in response to changing populations and demand, giving each system unique characteristics that determine the utility’s approach to connecting intermittent resources. Different regulatory environments and populations may also require different approaches to integrating customer-owned systems. There are costs, legacy systems and infrastructure to consider as well. There is no single solution or formula for utilities to follow; each utility much determine their own best approach.
Collaboration is essential
Adding customer-sited resources to a utility’s generation mix adds new complexity—both internally and externally. Planning for the future requires a holistic view; one where the utility must not only understand its own resources and plans, but also those of its customers, regulators, and the developers in its service territory.
Start Preparing Now
The main message from the utilities in the eye of the storm to those still with low penetrations of customer-sited resources is to start preparing now. Capture your load profiles, develop your modeling tools, and set up the customer systems that will allow you to not only ride through the storm, but operate your grids safely and reliably in the new landscape.
EDITOR’S NOTE: Sonja Berdahl is a project leader with the National Renewable Energy Laboratory in Golden, Colorado. Integrating Intermittent Resources is the third guide in the “Voices of Experience” series. DOE is starting a new working group that will kick off in January 2018 to explore how utilities are leveraging their AMI networks and meter data to optimize operations and offer customers new products and services. More information can be found here.
