Backup generator for a theater

[sotonfan]

My boss has asked me to develop a proposal for installing one or more backup generators for our theater. We have a 1700-seat auditorium on one side, and a 350-person ballroom on the other side. Twice in the past few years we have had a major power outage on our block when there was a wedding on one side and a show on the other at the same time. It was a real mess, for patrons and also for promoters and bands. (Loading out a full rock band in the dark is something I hope never to do again, but it was less painful than moving a wedding across town with an hour to spare.)

I talked to the power company, who calculated our peak load in the heaviest time of the year was 312KW.

Does anyone have experience with this process? Is my boss asking for something impossible? Or is this a reasonable idea? We have room on our roof for generators - especially if they can run on natural gas. There's very little footprint on the ground for anything.

Thanks for any suggestions on how to start tackling this one. Pretty sure we can't start until COVID is behind us, since I'm sure it will require some fund-raising...
Andrew

 

[dmx]

Andrew,
The cost for a 250Kw generator and electrical interface will likely price you between 65 - 125K depending on your location and features requested. Perhaps a more realistic option would be to hire an electrician to install a generator tie-in, where you would rent a generator in case of emergency. This may not be feasible during non-standard business hours if you are in the event industry.
Another option to consider is load shedding. Even in our military installs, rarely are our buildings wired for 100% emergency backup loads. Essential components (lighting/ critical equipment) are always included but many rooms have 1-2 backup circuits at most. I think your best bet would be to consult with a local firm and start gathering quotes, perhaps for multiple configuration options.
--Matt

(For the record, one of our installs includes a 1.3MW generator paired with a 750Kw unit used for mission-essential loads. It is really more of a question of budget than size.)

 

[RonHebbard]

My boss has asked me to develop a proposal for installing one or more backup generators for our theater. We have a 1700-seat auditorium on one side, and a 350-person ballroom on the other side. Twice in the past few years we have had a major power outage on our block when there was a wedding on one side and a show on the other at the same time. It was a real mess, for patrons and also for promoters and bands. (Loading out a full rock band in the dark is something I hope never to do again, but it was less painful than moving a wedding across town with an hour to spare.)

I talked to the power company, who calculated our peak load in the heaviest time of the year was 312KW.

Does anyone have experience with this process? Is my boss asking for something impossible? Or is this a reasonable idea? We have room on our roof for generators - especially if they can run on natural gas. There's very little footprint on the ground for anything.

Thanks for any suggestions on how to start tackling this one. Pretty sure we can't start until COVID is behind us, since I'm sure it will require some fund-raising...
Andrew

@sotonfan Having space and natural gas available on your roof is only part of the puzzle:
Will your roof support the physical point load of a V12 generator?
Several theatres within a 50 mile radius of my abode have backup generators. Keeping them warm and ready to rock during Canadian winters is another expense and consideration.
Toodleoo!
Ron Hebbard

 

[DrewE]

Are you looking to be able to continue the show or event uninterrupted when the utility power unexpectedly goes out, or simply to resume it after a hopefully brief interruption? Or, perhaps, to not necessarily have it continue, but simply have greater comfort and safety for getting people on their way and cleaning up afterwards?

The first rather obviously requires, in addition to the generator, a not insubstantial UPS system, and all the expense and space and maintenance involved in that. The second scenario may involve more than a brief interruption if there are many computerized show systems that have to be reset, reloaded, and advanced to an appropriate restarting point. Ideally such systems would be on their own UPS or other backup power source to avoid such a delay, but I suspect enforcing that especially with outside groups using the facility would prove impracticable.

(How well acoustically isolated is the roof from the venue interior?)

 

[sk8rsdad]

My $.02 is while it is possible to install and maintain a backup generator, it's not very practical for a theatre, leastways not for the purpose of going on with the show. If the facility is a designated emergency center that might be a different matter. My venue has battery backup on some critical systems like booth consoles and emergency lighting. It's enough to ride out momentary interruptions or evacuate the theatre for prolonged outages.

 

[RonHebbard]

Are you looking to be able to continue the show or event uninterrupted when the utility power unexpectedly goes out, or simply to resume it after a hopefully brief interruption? Or, perhaps, to not necessarily have it continue, but simply have greater comfort and safety for getting people on their way and cleaning up afterwards?

The first rather obviously requires, in addition to the generator, a not insubstantial UPS system, and all the expense and space and maintenance involved in that. The second scenario may involve more than a brief interruption if there are many computerized show systems that have to be reset, reloaded, and advanced to an appropriate restarting point. Ideally such systems would be on their own UPS or other backup power source to avoid such a delay, but I suspect enforcing that especially with outside groups using the facility would prove impracticable.

(How well acoustically isolated is the roof from the venue interior?)

If you want to see "a not insubstantial UPS system, and all the expense and space and maintenance involved in that", visit any of Las Vegas's serious casino's. If patrons are gambling, they want zero distractions / interruptions and have literally tons of weight and money invested in batteries to power their UPS's.
@derekleffew Care to comment?
Toodleoo!
Ron Hebbard

 

[RonHebbard]

My $.02 is while it is possible to install and maintain a backup generator, it's not very practical for a theatre, leastways not for the purpose of going on with the show. If the facility is a designated emergency center that might be a different matter. My venue has battery backup on some critical systems like booth consoles and emergency lighting. It's enough to ride out momentary interruptions or evacuate the theatre for prolonged outages.

Having your Clear Com / production intercom and God mic' system on a UPS is also money well spent for inter-department communication and crowd instruction / control.
Toodleoo!
Ron Hebbard

 

[MNicolai]

We do a lot of projects with standby and/or life safety generators. In most cases, 100% transfer of the load is not the target goal unless it's a data server farm, EOC, or call center, in which case there is N+1 redundancy sharing the total load across multiple generators with one spare ready to go if one of the others has a fault. Most projects end up having load shedding to a generator or sometimes a UPS battery farm with inverters for the purposes of keeping only essential systems and life safety lighting online. Depending on where the venue is based, that may or may not involve major mechanical systems -- often only data closets will remain temperature controlled and other mechanical systems will be shut off.

If you go through the trouble of installing a generator only to have to put it on the roof, then you are going to have sound and vibration problems that will make it difficult to keep your event going uninterrupted anyway, in addition to the structural considerations associated with that. Other considerations for a rooftop installation is that you often need to provide screening so it's not an eyesore if it's visible from the street, and having it on the roof means the noise from it will travel a long distance. Which will make you the subject of noise complaints when you cycle it monthly to keep it in good working order.

Impossible? Not at all. Cheap? Also not at all. 350-400kW plus redoing your switchgear to accommodate an ATS as well as any life safety implications that may be involved is not a small undertaking. Possible, but with a price tag.

Segmenting out critical systems and only transferring those to a generator is more digestible -- but even that is no small undertaking because you may still require a sizable overhaul of how your panelboard distribution to branch circuits are configured. As with all things though, anything is possible if you draw your idea on the back of a big enough check.

 

[derekleffew]

... patrons are gambling, they want zero distractions / interruptions and have literally tons of weight andat", visit any of Las Vegas's serious casino's. money invested in batteries to power their UPS's.
@derekleffew Care to comment?

Okay, since I've been dragged unwillingly into this, a story...

Upon opening, a major resort proudly bragged of its ten or twelve, can't remember, Caterpillar back-up diesel generators. A few years later, the entire property went dark and closed for THREE days. While building a second tower, workers had some how cut through the wrong feeder.

Bellagio blackout creates surreal scene

Rather than the usual sound of casino games, silence greeted thousands of Bellagio guests Sunday, as the 3,005-room resort was plunged into darkness because of a massive power failure.

lasvegassun.com

As for UPSs, what I've seen is no different than any other large IT services install.

 

[SteveB]

At the OP, you want to be contacting an electrical engineer who can ascertain what needs to be in backup, then design an appropriate system that’ll meet your need as well as local code. You cannot take this on yourself, too many legal issues involved.

 

[Ben Stiegler]

We do a lot of projects with standby and/or life safety generators. In most cases, 100% transfer of the load is not the target goal unless it's a data server farm, EOC, or call center, in which case there is N+1 redundancy sharing the total load across multiple generators with one spare ready to go if one of the others has a fault. Most projects end up having load shedding to a generator or sometimes a UPS battery farm with inverters for the purposes of keeping only essential systems and life safety lighting online. Depending on where the venue is based, that may or may not involve major mechanical systems -- often only data closets will remain temperature controlled and other mechanical systems will be shut off.

If you go through the trouble of installing a generator only to have to put it on the roof, then you are going to have sound and vibration problems that will make it difficult to keep your event going uninterrupted anyway, in addition to the structural considerations associated with that. Other considerations for a rooftop installation is that you often need to provide screening so it's not an eyesore if it's visible from the street, and having it on the roof means the noise from it will travel a long distance. Which will make you the subject of noise complaints when you cycle it monthly to keep it in good working order.

Impossible? Not at all. Cheap? Also not at all. 350-400kW plus redoing your switchgear to accommodate an ATS as well as any life safety implications that may be involved is not a small undertaking. Possible, but with a price tag.

Segmenting out critical systems and only transferring those to a generator is more digestible -- but even that is no small undertaking because you may still require a sizable overhaul of how your panelboard distribution to branch circuits are configured. As with all things though, anything is possible if you draw your idea on the back of a big enough check.

That last bit is poetry, Mike!

 

[rphilip]

... when you cycle it monthly to keep it in good working order.

I want to emphasize this point.

I work on a university campus and several buildings have backup generators of various sizes. The one for the IT building get tested, with load weekly and has never failed when needed (but it did get very close one). In the event of a power failure the machine room rides over on UPS and the rest of building is back online in <10s + any reboot time. The rest that might only get started every few months seem to invariably take a few hours to get going. I very highly recomend you make sure that any generator gets tested under load regularly (no less than monthly and weekly isn't bad) and any problems are followed up on promptly.

 

[FMEng]

Having dealt with generators from 7 kVA propane to 400 kVA diesel, for broadcast studios and transmitter sites, I concur with everything Mike N and Steve B said. The goal should not be running everything. The goal should be running the barest essentials. Otherwise the size of the generator, and the cost of fuel and maintenance just sky rocket. For example, if the peak load is 350 kVA, you'll need a much larger generator to handle motor starting of HVAC systems. Start the list of what's essential, and what's not, then get an electrical engineer involved. UPS for anything beyond booth equipment and announcement PA would be a waste of money.

 

[RonHebbard]

I want to emphasize this point.

I work on a university campus and several buildings have backup generators of various sizes. The one for the IT building gets tested, with load weekly and has never failed when needed (but it did get very close once). In the event of a power failure the machine room rides over on UPS and the rest of building is back online in <10s + any reboot time. The rest that might only get started every few months seem to invariably take a few hours to get going. I very highly recommend you make sure that any generator gets tested under load regularly (no less than monthly and weekly isn't bad) and any problems are followed up on promptly.

In my area, hospital generators are typically ran under load weekly for ~one hour.
Within 2020 I was hospitalized in a wing I'd helped build in 1969 during my apprenticeship. When I heard the hospital wide warning announcement, followed by the roar of the V12 diesel several stories above my bed, followed by the barely perceptible blink as the Robonic (Brand) transfer switch threw, I knew EXACTLY where I was.
Toodleoo!
Ron Hebbard

 

[FMEng]

Diesel generators really need to be exercised at least monthly, or they will act up when needed. Most of the clocks can only do it weekly. You'd be surprised at how much run time is accrued just by exercising the beasts. They also "wet stack" when run without load, so they need a run with a good load periodically, to cook the crud out of the exhaust system.

I'll never forget the year we moved into new studios, with a brand new, 125 kVA, Caterpillar diesel. About a month after we moved in, we had a 3 hour power outage, right in the middle of "drive time." At that point, the generator had been load tested and exercised some 20 hours. Yet, when duty called, the alternator failed causing the generator to produce no output. The result was the longest off-air period in my entire career. Naturally, once the mechanic arrived, it worked fine. After several service trips, they found an intermittent rectifier module inside the alternator.

 

[macsound]

In my area, hospital generators are typically ran under load weekly for ~one hour.
Within 2020 I was hospitalized in a wing I'd helped build in 1969 during my apprenticeship. When I heard the hospital wide warning announcement, followed by the roar of the V12 diesel several stories above my bed, followed by the barely perceptible blink as the Robonic (Brand) transfer switch threw, I knew EXACTLY where I was.
Toodleoo!
Ron Hebbard

I'm happy to hear there were some good memories and moments of internal fuzziness associated with your hospitalization. It's always nice to have a positive experience distract you while you're on the mend.
As always, happy you're still with us sir.

 

[Ancient Engineer]

I have a bit of experience and would agree will all of the above. If you really need 100% load transfer you are looking at a substantial ground footprint. We had a ginormous (possibly larger) Liebert UPS that would take the load for exactly 20 minutes.

The generator (750kW) took less than a minute to fire and could be 100% loaded in about 12 minutes. The electronic changeover in the UPS was magnificent to observe as well as the raft of STACO automatic regulators doing their thing...

The footprint for the generator building was about 75' x 150' and housed the UPS batteries (lead-acid) and ventilation. The 35K gallon fuel tank was under the floor. The "hotel" load for the place was around 125kW, but the full load in August with tons of A/C starting all at once was about 470kW.

But at the outlet, the blip was under 4% RMS going in any direction. (mains to ups, ups to gen, gen to mains)

Pretty awesome.

 

[sotonfan]

Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go.

I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.

 

[TimMc]

Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go.

I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.

The cost/benefit needs to be calculated for having enough generating capacity to put on a show, as that presumes customer-facing things will work: restrooms, concessions, bar, merch, valet parking, climate control and that all auditorium/stage house things work, too. IOW I'm guessing capacity at 100% of load, plus some overhead. How much will this cost? How much will the *facility* loose if the show does not go on? Is the facility the sole or primary promoter for outside shows?

If the whole city is in the dark (except for the hospital), will people come to a show? No shower, no dinner...

Now... I'm not an EE. I don't know what stuff like this costs these days... but I think you're looking at between $250k-$500k. That might just be a down payment... but you can do a lot of work inside your theater or facility for that kind of coin and have it pay back every time the building is used.

 

[Jay Ashworth]

I have a bit of experience and would agree will all of the above. If you really need 100% load transfer you are looking at a substantial ground footprint. We had a ginormous (possibly larger) Liebert UPS that would take the load for exactly 20 minutes.

The generator (750kW) took less than a minute to fire and could be 100% loaded in about 12 minutes. The electronic changeover in the UPS was magnificent to observe as well as the raft of STACO automatic regulators doing their thing...

The footprint for the generator building was about 75' x 150' and housed the UPS batteries (lead-acid) and ventilation. The 35K gallon fuel tank was under the floor. The "hotel" load for the place was around 125kW, but the full load in August with tons of A/C starting all at once was about 470kW.

But at the outlet, the blip was under 4% RMS going in any direction. (mains to ups, ups to gen, gen to mains)

Pretty awesome.

In an install that big, did you not have some staging in the HVAC controllers to avoid *all* the motors dead-starting simultaneously?