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What should be the role of a transmission provider in interconnecting distributed energy resources?

Rao Konidena's picture
Independent Consultant Rakon Energy LLC

Rao Konidena found Rakon Energy LLC because Rao is passionate about connecting clients to cost-effective solutions in energy consulting, storage, distributed energy resources, and electricity...

  • Member since 2014
  • 189 items added with 40,216 views
  • Mar 10, 2021

MISO will be discussing interconnection rules around DERs at March 16 Interconnection Process Task Force.

That prompts the question -what is the role for MISO as a grid operator and transmission provider in approving interconnections on the distribution system?

If DER stays on the distribution system, it is the distribution utility's responsibility - right? What if, the DER wants to participate in the wholesale energy market? Then, that resource must go through the interconnection queue - right? But at what MW size does that make sense? 100 kW is too small, perhaps 500 kW?

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Good question Rao, and certainly a lot to be determined by each RTO/ISO as FERC 2222 is outworked. 

The challenge is also being looked at and tackled in other international markets as well, with often the key sticking points between the role of the Market operator and distribution entity.


Rao Konidena's picture
Rao Konidena on Mar 25, 2021

Thanks Don. My sense is compared to Europe and perhaps Australia - US does not yet have distribution system operators. May it is time for DSOs in US.

Right now MISO does not care about distributed generation until the aggregate flow back to the transmission system is 75MW. So if your the 500KW project that tips the scale to the MISO queue, you will probably get slammed with some huge costs. The independent transmission providers in MISO (e.g. ITC, ATC) have both in the past said that there was "no" affect on their system at 10 MW reverse power flow into their system (I have not had a situation where at one substation there was more than 10MW, so I don't know an actual number. 

WARNING: These are based on historical actual situations, with FERC 2222, FERC 841/2/5 - those numbers may be changing, so check before deciding to build. 

The far bigger issues are getting interval ahead from MISO on storage in "continuous" mode for utilities who have it installed on their distribution system, but are not transmission owners. It might be a peak day, with great solar in your area and you want to use the battery to reduce power flow on the circuit and MISO may need that battery discharging overloading your circuit by 130 or 150% in extreme cases. 

Again all of this is based on historical actuals and your mileage will vary (not might).

Richard Brooks's picture
Richard Brooks on Mar 13, 2021

Doug, I like your qualification regarding Order 2222, which I agree with. Based on my research, Order 2222 will open the floodgates for thousands of BTM PV to be aggregated and participate in the wholesale capacity markets on day one. These existing resources are already operational and do not require an interconnection process - they're already connected. Business practices and data standards are needed to enable these DER's to participate in wholesale markets. NAESB has one such initiative underway now:

Rao Konidena's picture
Rao Konidena on Mar 25, 2021

Doug - I never understood the 75 MW limitation. Are you referring to the PURPA QF definition?

Your overall point is a good one, I believe RTOs need some guidance on how to treat hybrid interconnections. We can expect more RTO involvement with the rise in DERs.

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