Map sparks questions on surge of solar arrays

ADDISON COUNTY — Ellen Kurrelmeyer looked warily at a stack of applications for new solar power development in Addison County. The Addison County Regional Planning Commission member also considered a map produced by Green Mountain Power that shows power lines in the county are stretched thin by a number of solar arrays already here.
“So are you trying to tell me that we shouldn’t be seeing more heaps of these” applications, Kurrelmeyer asked two GMP officials who came to a planning commission meeting last Thursday to explain the map.
The commission’s Section 248 committee, which Kurrelmeyer chairs, met with GMP Vice President of Field Operations Greg White and Chief Innovation Executive Josh Castonguay to understand the implications of a new “Solar Map” put online recently by GMP. The online Solar Map (found at shows that the majority of Addison County distribution lines are “approaching capacity” or have “little to no capacity” to carry more locally generated solar or other renewable power, in contrast to other parts of the state in the GMP service area.
Kurrelmeyer and Section 248 committee members are tasked with being the county’s eyes and ears in taking a first look at new petitions for a Certificate of Public Good from developers of proposed renewable generation projects. State guidelines give towns and regional planning commissions 45 days in which to provide input on these proposals, and only after that window can developers apply to the Public Service Board itself. The state’s intent is to give local entities the opportunity to provide input on the projects, and for appropriate changes in the proposals to be made, before developers make their formal request for an OK from the regulator.
For Green Mountain Power, the map is a way to show customers and potential developers where solar energy is being generated and how it ties into the electric power grid within the GMP service area.
“GMP is committed to siting projects close to where they’re needed,” said GMP chief spokesperson Kristin Carlson. “So, if you’re a solar developer and you’re looking to do a project, you can look at the sites that are green, yellow or red and that should help you determine where there is capacity.”
For Addison County residents — including members of the regional planning commission’s Section 248 committee — the map provides a useful snapshot of solar development patterns. The map is interactive and lets one zoom in from a bird’s eye view of the whole state to a single street, GMP circuit or substation.
But, as witnessed by Thursday night’s Q&A, the picture of Addison County that the map provides raises a number of questions. As circuits approach capacity, will there still be room for small home and business roof-mounted systems? As circuits approach capacity, will developers of large solar projects seek more suitable sites elsewhere? Or, will they instead continue to want to capitalize on Addison County’s open fields and relatively flat topography and be willing to pay for power grid upgrades? How will this affect ratepayers? And will the Public Service Board continue to support the current uneven pattern of development statewide or will it regulate toward a more even pattern of solar development statewide?
The GMP Solar Map color codes electrical distribution lines to show where capacity for new solar is abundant and where the grid is at or approaching capacity. The map shows green for “good,” yellow for “fair,” and red for “poor.” GMP’s website further explains that green means having “available capacity,” yellow means “approaching capacity,” and red means “little or no capacity.”
GMP’s White and Castonguay explained that the color and rating system includes projects proposed to the Public Service Board but not yet granted a Certificate of Public Good. Not all projects in the queue will necessarily come online, they said. So the load on a given circuit — and how close it is to capacity — is somewhat fluid, they emphasized.
GMP plans to update the map weekly as new projects are proposed or as projects fall out of the system, according to Carlson.
A quick look at the map shows predominantly green across the GMP service area — GMP provides roughly 75 percent of the state’s electricity — with small squiggles of red near Rutland, St. Johnsbury, and White River Junction, and dabs of yellow near Bennington and Rutland.
Addison County, however, stands out as a large mass of red and yellow lines, with very little green.
About 77 percent of the county’s 6,219,151 feet of electricity distribution lines are at or are approaching capacity, according to Michael Butler, GMP’s lead advanced metering infrastructure operations analyst.
According to the map, 23 percent of Addison County transmission lines are green (have available capacity), 45 percent are yellow (are approaching capacity) and 32 percent are red (have little to no capacity).
The map tells an even more striking story when broken down by town:
•  17 percent of Addison County towns are all green or almost all green (Goshen, Granville, Hancock, Leicester)
•  39 percent of Addison County towns are all yellow or mostly yellow (Bristol, Cornwall, Lincoln, Middlebury, Orwell, Ripton, Salisbury, Shoreham, Whiting)
•  35 percent of Addison County towns are all red or mostly red (Addison, Bridport, Ferrisburgh, New Haven, Panton, Vergennes, Waltham, Weybridge)
•  9 percent of towns are close to equal mixes (Monkton is a mix of green, yellow and red; Starksboro is a mix of green and yellow)
The preponderance of red and yellow lines in Addison County, said Carlson, has “to do with the number of projects that have been built there and are being proposed.”
Indeed, Addison County boasts 674 solar projects and has 18.6 megawatts of solar installed (enough to power 3,900 homes a year), according to GMP data.
Addison County has become a magnet for these projects because of cost and efficiency. The region has a lot of farms on flat land along three-phase lines, and that’s where it’s most cost-effective for developers to build and that’s why so many of the Addison County distribution lines are red, according to Robert Amelang, an electrical engineering consultant with more than 40 years experience in the field.
For Amelang, the tight knot of red and yellow distribution lines in Addison County in comparison with the green showing across the rest of the state is a sign that “we’re going too fast with solar in this state … The whole state should be either green or yellow, and we shouldn’t have any red.”
Asa Hopkins, director of the Planning and Energy Resources Division of the Public Service Department, does not agree.
“I don’t think we’re moving too fast, I think we’re moving fast enough that we run into different kinds of growing pains,” Hopkins said. “This is a particular sort of grid kind of growing pain, about figuring out what it means to have this much distributed generation. It has happened that Addison County in particular has some sort of relative mix that makes it more attractive for solar. Whether it’s just because it’s flat and well-drained and sunny or if there are also interconnection benefits — there’s a VELCO substation in New Haven. So folks saw that as an attractive place to go and went there, but it’s becoming less attractive because the ability to interconnect is being used up.”
For the ordinary person wanting to install solar panels to power a home or small business, a glance at the map makes it reasonable to wonder if there’s enough room on circuits labeled as having little to no capacity. On the red lines, will large projects generating 150 kW to 2.2 megawatts push out homeowners and small business owners, Kurrelmeyer wondered at Thursday’s meeting.
“My concern is the average person who wants to do a rooftop or a small array in their yard ending up being pushed out because you’ve reached capacity, as opposed to an out-of-state company that’s coming in and putting up and leaving and taking their tax breaks with them,” she said. “Plus they’re creating an eyesore for the town that they’re dumping into whereas a rooftop is hurting no one. I don’t know how we solve that.”
“Our intent is to continue to let rooftops connect,” said GMP’s White. “One advantage of a rooftop project is that they consume … most of the solar (power generated) locally … so you don’t have the issues of it coming back onto the system.”
Small, rooftop solar arrays don’t add much or any power onto the grid, which is a good thing, Castonguay said.
“We like the small rooftop stuff,” he said.
Plus, he said, GMP was exploring energy storage options that could be used by both small and large solar arrays to keep power local until it is needed.
When queried about specific sites, White and Castonguay reiterated GMP’s commitment to supporting small rooftop installations.
What if, for example, you lived on Field Days Road and wanted to put solar panels on your rooftop? If you click on the Solar Map to add streets (one of the basemap layers currently available) and zoom all the way down to Field Days Road, the map shows that the substation for the Field Days Road circuit, Weybridge circuit WY-G81, is close to 2 megawatts over capacity. Could one still put rooftop solar on one’s house if they were on that circuit?
“We’re going to continue to make sure we can do the rooftop stuff,” Castonguay said. “While you have areas like this area showing the red, it’s a macro level. There’s a lot of moving parts in there. There are projects that may or may not end up coming into fruition. Our goal for the key ones is to continue to have the rooftop stuff. The rooftop is good for a number of reasons. It’s literally on top of load.”
Asked whether Addison County — with its flat, open topography — could expect to see fewer large arrays as developers look for spots where there’s more capacity on the grid or whether the county would instead see more and more upgrading, White answered, “That’s a good question.”
He continued, “The original intent of the map is to show areas where there’s significant congestion, and in particular a larger project (can) look at an area that may not have that congestion. But ultimately the developers and the communities — the whole land use issue and the siting issue — is going to be figured out by multiple stakeholders.”
Castonguay added, “The point of the map is to be an indicator and it came as a result of the solar community, too, asking for more transparency into where is there the solar bumping up to grid where now it could be more expensive to connect or this or that. So it does give them an indication. And somebody looking to build a larger project, looking at the map could make their own decisions based on it. No matter what they do we need to study that project through its process.”
Reporter Gaen Murphree is at [email protected].

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