One of the most significant developments in interconnection and grid modernization policy in the last five years has been the introduction of tools that enable customers to get information about the grid at a particular point of interconnection in order to help inform future interconnection applications. Increasingly, these new grid transparency tools are streamlining interconnection processes for customers and project developers by providing insights into ideal locations for distributed generation projects. These tools can also be used to help all parties more quickly identify locations on the grid that may be less constrained and/or may be expedited without a more detailed and costly utility study.

Now that numerous states and utilities have adopted these tools, the question is how well are they working? Exactly what are these tools, and what are the stakeholder experiences using them to get distributed renewable energy projects connected to the grid faster, cheaper and easier?

What are grid transparency tools?

Though there is a wide range of tools and approaches being deployed to increase transparency into the grid, two in particular stand out; pre-application reports and utility distribution system maps, such as heat maps and hosting capacity maps.

• Pre-application reports allow customers to obtain certain interconnection information about the grid at a particular location from a utility before submitting an interconnection application. A basic pre-application report typically costs $300 and requires the utility to provide up to 13 different pieces of readily available information (e.g., line voltage, existing generation capacity, available capacity at the proposed site, etc.).
• Distribution system maps provide data in an online interactive map format which allows users to visually locate circuits which may have more available capacity for new projects. Heat maps, which have been developed by several utilities in different states (e.g., New York's Stage 1 maps or California's Renewable Auction Mechanism, or RAM, maps), provide basic data, which can include line voltage, load, and interconnected as well as queued generation capacity. Hosting capacity maps go beyond the basic information provided by heat maps by also giving customers the estimated remaining amount of distributed energy resources (DERs) that can be accommodated on a line without requiring infrastructure upgrades. The available capacity on the grid (known as hosting capacity) is determined by utilities through varying methodologies that approximate DER capacity limits.

Increasing efficiency and reducing project costs

For distributed renewable energy project developers, the availability of grid transparency tools can help streamline efforts to connect projects to the grid, which can translate into more affordable and predictable projects for customers. Solar project developer Borrego Solar, for example, has operations in California, Massachusetts, Illinois and New York and routinely navigates the various interconnection processes and tools in each state.

"We use pre-application reports all the time and they have become integral to our project development process," said Borrego Utility Electrical Engineer Shay Banton.

From a pre-application report, Borrego is able to make a preliminary assessment of the feasibility of installing a solar facility in a certain location. This can reduce their costs considerably by enabling them to pursue only projects that are more likely to be financially viable.

Similarly, solar developer Ecoplexus has benefited from the upfront information pre-application reports and distribution system maps provide. Ecoplexus Vice President of Southeast Development Mike Wallace confirmed that these tools have been informative and helpful in his region. Though heat maps are less prevalent in the Southeast, Ecoplexus regularly uses pre-application reports in North Carolina, South Carolina and Florida.

​"Pre-application reports and heat maps are useful tools to help developers understand the needs of the utility and avoid grid constraints," Wallace stated. "The more information we have, the better we are able to make informed decisions about where to locate a project." 

Additionally, developers have been able to use grid transparency tools to effectively estimate costs and the amount of time it will take to build projects. Tim McDuffie, Chief Engineer at CalCom Solar, regularly uses pre-application reports and heat maps in California to help provide his clients with some visibility into the risks associated with a project.

"This level of front-end due diligence helps ensure that we’ve exhausted every avenue to provide the maximum possible transparency as to the timelines and cost associated with interconnection," McDuffie said.

Pre-application reports and distribution system maps can also benefit utilities. Although resources are required to develop these tools, they can lead to fewer applications for projects that will not be built. Publicly accessible maps, in particular, can also reduce the number of information requests from customers since grid characteristics and other data are already provided within the maps. In addition, maps can help to identify locations where projects could provide benefits to the grid.

Room for improvement

The impact of these tools can be greatly diminished if they do not provide sufficient data. For example, in Massachusetts, pre-application reports are not required to provide information on total or available generation capacity at a proposed grid location.

"If the reports don't include certain capacity and load info, it can become a guessing game as to whether or not we can interconnect without having to pay for costly upgrades," said Banton.

Ecoplexus' Wallace would like to see these tools identify where capacity is needed and not just available. "This could help to address concerns about adding capacity that may be deemed less beneficial or unnecessary to grid operations," Wallace added.

The usefulness of distribution system maps is not only a function of the data they provide, but also how frequently they are updated. Maps that are only updated annually can become quickly outdated and can lead to customer decisions made on the basis of inaccurate data. Distribution system maps should be updated at least monthly for them to be useful for customers.

In some states, regulators and stakeholders are working to update these tools to ensure that customers can access even more granular information. In 2016, California adopted an enhanced pre-application report that provides additional information for a higher fee than the standard report. CalCom's McDuffie found the standard reports useful but was a strong advocate for the option of receiving more detailed information.

"The enhanced pre-application reports provide us greater certainty in classifying project locations as favorable or unfavorable," McDuffie said.

As increasing amounts of distributed energy resources are added to the distribution system, and as strategies to reduce project costs become more important, grid transparency tools are only increasing in importance. Deploying them more widely across multiple utility service territories (and across multiple states) helps customers avoid costly upgrades and project delays, making connecting to the grid more cost-effective and expedited. To ensure they can be utilized for broader grid transformation goals, grid transparency tools must be updated frequently and as accurate as possible to allow greater visibility into the state of the grid.