A reader recently called and asked if Block Island Power Company ratepayers, given that they are paying for it, owned the new substation that was built by National Grid to connect to the Block Island Wind Farm cable. We put the question to BIPCo President Jeffery Wright:
Q: Since Block Island ratepayers are paying for the construction of the substation, do the ratepayers also own the substation?
A: The Block Island ratepayers are paying for the portion of the National Grid substation that is required to serve BIPCo. That includes a power transformer, protective breaker, switchgear and the small section of line that connects BIPCo to that station. BIPCo is paying National Grid for that expense over a six-year period that ends on May 1, 2023. This represents approximately five cents per kilo-watt hour of the Transmission portion of everyone’s monthly bills.
Q: Is the substation essential to providing electricity to Block Island customers?
A: Yes, this station is necessary to connect BIPCo to the Sea2Shore Cable.
Q: Why was the existing substation not used to connect the cable?
A: The existing substation contains just our distribution equipment, which is all rated at 2,400 volts. The National Grid substation is primarily used to interconnect the Deepwater project, with a side connection to us. Their equipment is all rated 34,500 volts, which is why that special transformer is in place there; to convert the voltage from 34,500V to 2,400V.
Q: If the substation had a catastrophic failure, how does the electricity provided by the backup generators get distributed to Block Island customers?
A: The station design is very robust so a catastrophic failure would normally be limited to a single component within the station, most of which can be readily replaced with spare equipment. The one exception, though, is the transformer that is required to connect BIPCo. National Grid does not have a spare. If a failure required a full rebuild, the lead-time for a new one could be as long as six months, making this the most critical item in the station.
Q: Has there been a cost analysis of replacing the substation if that ever occurred?
A: BIPCo is not aware of the total cost of the station that National Grid built. The portion — all components — that are required to serve BIPCo would cost approximately $2.3 million to rebuild.