Author: Herve Billiet                Published: 8/6/2020                  IPSUN Solar


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A couple of hours ago the DC Public Service Commission issued an order to raise the size limits on net metered systems—which mostly means rooftop solar, in practice.

 The order becomes effective upon its publication in the DC Register, which might come tomorrow (the Register comes out on Fridays). My reading is that as soon as it takes effect, the size limit will rise from 100% to 120% of historical usage. It will rise again, to 140%, on January 1, and then 160%, 180%, 200% over the following years. A few points:

  • There’s an opportunity to pause the increases if adverse effects are found for the power distribution system. The order directs the working group that generated this rule change to monitor for such effects. I doubt this will amount to much since Maryland has been at 200% for about a decade without apparent problems.
  • As Kyle has pointed out, “historical usage” is not defined in the rules. This gives Pepco discretion in defining it, and in principle gives customers discretion in challenging Pepco’s definition. But Pepco has long had that discretion, and I think sometimes has used it in favor of customers who are, say, planning on buying an EV. Presumably Pepco will, for a baseline, continue equating each kW of nameplate inverter capacity (not panel capacity) to 1200 kWh/year of production, and define historical production based on bills over the last 12 or 24 months. We should watch what Pepco does.
  • The rule change also stipulates that customers who generate a surplus on an annual basis will get a payout at the end of the year for the excess, at the wholesale/”generation” price per kWh.

 As I’ve written before, this change originated in a fight I picked with Pepco a couple of years ago. After almost 30 years of doing policy-relevant research and writing in my day job, without clear policy impacts, I’ve helped change policy in my spare time, which is nice.

 Many others contributed: Ipsun Solar was game for slowing our installation so I could pursue the original complain; Pepco lawyer Andrea Harper, after fending off my complaint, suggested I file a comment with the PSC in ongoing proceedings; patient staff at the PSC handled the comment, inserted the issue into the already weighty agenda of a new working group, and wrangled that working group over nearly two years; solar industry people and DC officials contributed energetically to the process; folks on this list files supportive comments.

 And the working group actually spent much of its time on smoothing the process for connecting Community Renewable Energy Facilities, work that was at least as important, but which I don’t understand as well.

 Power. Fully Yours.

Herve Billiet

Herve Billiet

Co-Founder and CEO

Management | Ipsun Solar

Power. Fully Yours

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