Interconnection Studies / Costs

[nrgmanager]

Hello, I am in the process of funding a renewable generator for parallel operation with the grid. I have a general idea of the costs associated with performing the interconnection studies, however wanted to hear from some real world people.
How mush would one estimate the cost for a complete interconnection study be?
Thanks

 

[rbulsara]

What size system? What type of generator? Also define interconnection study!

I have seen upward of $200,000 for (2) 2MW wind turbines interconnection "stability" study. I have also seen $20,000 for a "impact" study for 2 to 4 MW diesel generator interconnection. These are the studies required by and even performed by the utility companies. Any other feasibility studies would be separate by the Owner.

The kicker is after the study is done, utility company may come up with additional cost to cover whatever measures they may have to take to accommodate interconnected systems.

I am sure this varies by the region and utility companies. Some may have incentives to have those system interconnected, some may just be opposed to it.

Your best bet is to ask the utility company concerned. Even that may be very helpful until some concrete schematic design and application is in place.

Rafiq Bulsara

http://www.srengineersct.com

 

[dpc]

I agree with Rafiq - this will be dependent on the size and type of project and the location.

The connecting utility will expect you to pay for its engineering costs, including their feasibility study, system impact study and facility design. In addition, you will need to have engineering assistance on your side of the meter to develop the necessary interface system to meet the utility requirements. Most utilities will require full payment for each study up front, since they get so many "projects" thrown at them that never get past the planning phase.



David Castor

http://www.cvoes.com

 

[tlrols]

This is a tariff defined quantity, at least for the deposit. You need to get the Open Access Transmission Tariff (i.e. the OATT) for the utility you plan on interconnecting to. A phone call will get you the deposit numbers.

It does make a difference if you are a small generator, or a large generator trying to interconnect. The cutoff is 20 MW.

There are three studies that you need to provide deposits for, presuming you carry the project forward through all three phases:

1. Feasibility Study: typical deposits are around $10K
2. System Impact Study: typical deposits are around $25K
3. Facility Study: typical deposits are around $50K to $100K

Note that if you cannot demonstrate site control you will likely have to deposit an additional non-refundable deposit for the Facility Study phase.

Also, you will pay ACTUAL costs...usually this means you pay in addition to the deposit, however, I have seen several instances where part of the deposit was refunded.

I would budget for at least $250K to get through the study process...if you were risk averse then perhaps $500K might be a more appropriate number. This is for a large generation interconnection--a small generator interconnection (not under PURPA though) is less money.

The rough rule of thumb is that studies and direct assigned transmission costs should not exceed 10% of the project cost.

 

[nrgmanager]

Thanks guys, yes the size of the power plants will most likely have a sizing impact. In general though I am trying to understand what people have already paid, so the windfarm example and the pricing provided already helps. Thanks