Maine utility admits solar interconnection faults, hiring consultants


In case number 2021-0035 with the Maine Public Utilities Commission, electricity utility Central Maine Power Company (CMP) has admitted faults, and offered a settlement to tighten up their solar power integration work after last year’s interconnection fee debacle.

To meet the utility’s goal of improved interconnection processing, $550,000 will be spent hiring up to six new contractors to support the interconnection process. These individuals will be focused on the transmission level cluster study process for large scale projects. An additional $150,000 will go to fund an ongoing industry/utility working group whose purpose is to identify and troubleshoot grid connection challenges.

The $700,000 will come from shareholder money, and is not allowed to be covered by ratepayers.

The settlement also notes that CMP was at fault, and should have identified its ‘over voltage’ challenges far sooner in the project interconnection process. The utility said they will change analysis techniques in order to better estimate upgrade requirements.

Among these interconnection technique alterations is a pricing refinement. The utility CMP says they will “commit to provide cost estimates and construction schedules that are more detailed than the (-50%/+200%) cost estimate(s)” that they had been submitting.

Additionally, the utility released a list of projects – noted below – that are currently in long term cluster studies, slowing down their progression toward construction. CMP says they will work toward meeting the currently defined deadlines so as not to slow down these projects any further.

This settlement comes in response to massive interconnection fees that were sent out to solar developers after they’d already been given costs, and processes, for interconnection.

Per the Maine Renewable Energy Association, some examples of the upgrade changes that were received by solar developers include:

  • Developer A – Initially had received a fInalized Interconnection Agreement, with anticipated upgrade fees of $100,000. When the document was sent back to the utility for their final signature, instead of receiving the countersigned original agreement, a new upgrade fee of $1,420,000 was delivered, plus additional costs to be determined;
  • Developer B – With five projects completely built, and having a fully executed interconnection agreement, the developer received a notice that its projects faced an upgrade, along with additional fees and a longer processing schedule.
  • Developer C – A project with a fully executed Interconnection Agreement was reassessed for more than $12 million in upgrade charges for a project less than 2 MW in size.

After some public pressure, including the Governor Janet Mills calling for an investigation, managers at the company were able to find the errors of their ways. The utility responded with a letter stating that the initial upgrade estimates, which were in the range of $10-$15 million per substation, reflected the cost of a complete rebuild. The revised estimates delivered a range of $175,000 to $375,000 for required upgrades.


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