re: Explosion at SWB NOLA?

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Per Executive Director Korban's comments this evening at City Hall, both 20 Megawatt turbine generators 4 and 5 (TG 4 is in the same room as TG 5) are currently out of service. That leaves steam driven turbine generators 1 and 3, which are the least reliable units in the S&WB inventory (thus their plans for replacing them with a frequency changer or changers to convert Entergy 60 cycle power into S&WB 25 cycle power).

So as of today, the S&WB has the following power assets available:

25 cycle turbine 1: 6 megawatts (MW)

25 cycle turbine generator 3: 7 MW (downgraded from nameplate of 15 MW)

60 cycle turbine generator 6: 15 MW, can transmit 3.75 MW through a frequency changer on the Carrollton Water Plant to convert to 25 cycle power

Five 25 cycle electromotive diesel generators, each 2.5 MW, for a total of 12.5 MW of 25 cycle power

Frequency changer 3 at station D (aka station 17) on Peoples Avenue: 6 MW of 25 cycle power converted from 60 cycle Entergy power

Frequency changer 4 at station D (aka station 17) on Peoples Avenue: 6 MW of 25 cycle power converted from 60 cycle Entergy power

Frequency changer 1 at Carrollton Frequency Changer facility on Earhart: 6 MW of 25 cycle power converted from 60 cycle Entergy power

Frequency changer 2 at Carrollton Frequency Changer facility on Earhart: 2.5 MW of 25 cycle power converted from 60 cycle Entergy power

So in sum, they have a maximum of 49.75 MW, 20.5 of which is directly dependent upon Entergy. They have repeatedly said in the past that they need 52 MW to run the drainage system all out. In addition, that 49.75 MW is not really all available due to power network restrictions. For example, due to the configuration of some feeders, they can either feed one of the pumps at station 6 or the lone pump at station 12 in Lakeview, but not both (this was part of the reason station 12 didn't run until late on August 5).

With the temperature restrictions on turbine generator 6 preventing operation below 45 degrees (revealed last year), that 25 cycle availability drops further to 46 MW. Temperature are due to drop below 45 degrees early next week.

The winterization of turbine generator 6 is tied up in the fair share deal. $16 million in federal HMGP funds are due to be redirected by the state to cover the T6 winterization and replacement of turbines 1 and 3 with a frequency changer, but that has not happened yet, and very likely will not this winter.

The availability of 25 cycle power is actually even less if they are running some of the water distribution pumps on 25 cycle power, which they will to lessen their dependence on Entergy. Accounting for that and a T6 temperature restriction, available 25 cycle power could be as low as 43 to 44 MW.

What is the upshot of this? Basically it means returning to some of the 25 cycle power rationing among drainage pumping stations that was so prevalent during much of 2017 as 25 cycle turbine after turbine failed, most repeatedly. The areas of the city which would suffer most under such rationing would be those drained by stations 2, 3, and 12. Those three stations are exclusively powered by 25 cycle power. Stations 2 and 3 are located on North Broad, station 2 in front of Whole Foods and station 3 at the foot of the London Avenue canal. Station 12 is at the Lakefront just north of Russell's Marina Grill. Additionally, station 7, which also drains Mid-City and part of Lakeview, would also be vulnerable since most of its drainage is powered by 25 cycle, though there is one 1000 cfs pump there that runs on 60 cycle power, with a generator backup.

Additionally, relying on turbine generators 1 and 3 and lots of frequency changer power for anything is not a winning strategy. Turbine generator 3 was put back into service after the 2017 crisis without replacement of its rotor (estimated to cost $10 million). It ran close to nameplate at first, but since dropped to less than half. Turbine 1 is nearly 100 years old and has a poor track record. And frequency changers transmit much of their power via overhead lines, which is easily zapped out as tree branches along Broad Street and elsewhere rub the wires. Fortunately, they have the nearly new EMD's, which according to the November board meeting update, are all in service (though they have had hiccups too intheir short service life). I assume they will let the neighbors know they might be firing the EMD's up, because they are very loud.

If turbine generator 4 can be put back in service quickly, that will alleviate much of the pressure on the system. Korban claimed the damage to that turbine was minor. If they announce such a move in the next few days, the city should breath a sigh of relief. But until then, the power situation remains nearly as precarious as it was during the darkest days of 2017 prior to the August 5 flooding.

In the aggregate, the system is now much more dependent upon Entergy power than usual. This is not just true of drainage, but also water distribution on the east bank. They usually keep a mix of power sources for water distribution (they run 4 of 8 distribution pumps at all times), but with their two biggest 25 cycle sources out of the game, Entergy's power becomes more important, whether it is through directly running pumps or providing power to frequency changers. This increases the risk of pressure drops, possibly to the point of an east bank-wide boil water advisory.

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for a black woman she sure the frick is a terrible dancer.

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And frequency changers transmit much of their power via overhead lines, which is easily zapped out as tree branches along Broad Street and elsewhere rub the wires. 

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