I would like to comment on remarks made by Ed Martin on CBC Radio’s “On the Go” program of Feb. 6.
The purpose of this interview was to provide an update to the people of the island of the status of the island power supply on Feb. 6, a month after the catastrophic failure of the system of Jan. 4 and Jan. 5.
Mr. Martin acknowledged that Nalcor’s maintenance performance was below par and that some standby units that should have been available could not be put into service; because of this, load sharing measures had to be put in place starting on Jan. 2.
The question of how the failure of a single power transformer at Sunnyside led to the collapse of the system on Jan. 5 was not asked or discussed.
He advised that he had ordered his engineers to investigate these problems and to identify changes in operating procedures and control and protection design to ensure these problems can be avoided in the future.
Mr. Martin mentioned that standby capacity of 200 megawatts (MW) was available that day (Feb. 6) but, if we fast-forward for a year, the addition of Vale’s nickel operation, plus normal load growth, would reduce available reserve to about 120 MW, based on forecasts published in Navigant’s report.
This compares with the critical reserve capacity (buffer) of 160 MW — the largest generating unit out of service. This situation continues to deteriorate until 2017 when first power becomes available from Muskrat Falls. This is worrisome.
The Public Utilities Board has also engaged a consultant to inquire into these problems.
I encourage both Mr. Martin and the PUB to report the results of their investigations to the pubic as soon as these studies are completed.
The other major issue raised in the interview was the question of reliability of the system after interconnection of Muskrat Falls.
Mr. Martin advises that robust transmission line design standards will be used and that outages should be no more frequent than on the existing system.
Is it robust enough?
However, it should be noted, long radial transmission lines are particularly vulnerable, witness the many major power disruptions that have occurred on
the Hydro-Québec system: presumably HQ’s transmission lines were also built to “robust” standards!
Furthermore, the outage frequency rate is only one of the measures of reliability.
I submit that the duration of outages is a more significant parameter. Martin suggested that in the event power supply from Muskrat Falls is disrupted, an alternative supply could be obtained via the power cable link with Nova Scotia.
I question how practical backfeeding from Nova Scotia will be in reality. Firstly, Nova Scotia’s utility will need to restore their system first and only then will they be able/willing to supply power to the island.
And where will this power come from?
Available standby power from the Maritimes or the U.S. Northeast are most likely to be from thermal power stations that have long startup times — typically from six to eight hours for cold starts and two to three hours with pressure up.
Prolonged outages coincident with low temperatures will cause much hardship to island customers, as we know only too well.
I also note that Navigant shows that the Holyrood generating station will be retained in standby capacity until about 2021.
Is Nalcor planning to keep Holyrood in service as a backup supply?
I am not convinced that Nalcor has thoroughly addressed the issue of reliability after interconnect with Muskrat Falls. What are Nalcor’s plans to secure the island system in case of a disruption of supply from Muskrat Falls? Please explain, Mr. Martin.
Phil Helwig is a retired hydropower consultant.