Crossed wires at a utility jolt Maine’s solar developers


Interconnecting millions of rooftop and small-scale power plants across the nation is proving to be more complex than dealing with the few thousand that existed prior to the rise of distributed wind and solar.

Events in Maine over the course of just two weeks illustrate the kinds of growing pains that can impact a new solar power market and startle solar developers.

As reported on by local Maine writer, Tux Turkel, Central Maine Power (CMP) sent letters to dozens of solar developers announcing that it needed to dramatically raise interconnection costs for projects that had already paid those costs. Some of the developers who received letters reportedly had already built their solar power plants.

Turkel interviewed one company whose $1.4 million worth of power grid upgrades (powerlines, transformers, upgrade substations, and so on) had been paid, and whose interconnection costs were now being increased to cover an emerging “voltage issue” at one of roughly 100 substations impacted by revised cost estimates.

The state’s Renewable Energy Association outlined in a letter the upgrade cost changes that three solar developers received from CMP:

● Developer A – Had signed an IA with anticipated upgrade fees of $100,000. Instead of receiving the countersigned original IA, the developer got a new IA from the utility with an upgrade fee of $1,420,000, plus additional costs to be determined;
● Developer B – Received a notice that six of its projects faced an upgrade, along with additional fees and a longer processing schedule. Five of the projects were already built, with the sixth slated to break ground during the second quarter;
● Developer C – Received a notice that seven of its projects would be impacted: five had already executed IA’s and one was under construction. One project with a signed IA was assessed more than $12 million in upgrade charges for a project less than 2 MW in size.

The uproar led to a call by the state’s governor for a probe, which was launched by state utility regulators.

For its part, CMP responded with a letter rescinding the large interconnection fees. The utility said that its initial upgrade estimates were in the range of $10-$15 million per substation, reflecting the cost of a complete rebuild. It revised most of its estimates to a range of $175,000 to $375,000 for required upgrades. The utility said the new estimates cover upgrades to add transmission-over-voltage protection and tripping of distribution circuit breakers upon detection of an overvoltage condition.

In the end, the drama appears to have been an aberration. CMP executive chairman David Flanagan said that the stratospheric cost estimates were the result of a failure to communicate by midlevel engineers in a new department that has added more than 100 employees over the last 11 months.

Ultimately, the mistake was benign, but solar power professionals worry that such false alarms could have a cooling effect on solar investment in Maine.

Despite the hiccup, clean energy continues to march forward. On Jan. 15, Maine launched its latest request for proposals of procurement seeking 654,775 MWh of clean electricity.

John Fitzgerald Weaver is a solar power professional, known digitally as the ‘Commercial Solar Guy.’ His company has a construction license in Massachusetts, and directly manages projects in MA & RI. He may be reached at

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