Re: Backup Power Schemes

[wb8foz <wb8foz () nrk com>]

Eric Osborne sez:
> OK, let's see if we can turn this thread from BBN-bashing into something
> a bit more constructive.  I've seen several posts in the past few days 
> concerning optimal power backup strategies, both short and long term
> (battery, diesel, and/or nuclear).  Anybody out there care to share your 
> strategies?  

Putting on my EE hat:


        48vdc string, everything running off it is the #1 best
        answer from reliability. Time proven by THE paranoid folks
        in the world, Bell System Practices. 
        
        But the initial expense, space, weight, safety aspects,
        ventilation; all make this unlikely for anything except
        a tariff-funded CO. And it need generators. You can not
        really store many hours of energy in oxides of lead; it
        just costs too much. [Last time I asked, RBOC CO's had
        several hours worth of battery; in theory long enough
        to get a semi-mounted unit there if the local generator
        fails.]

That takes us back to UPSi on equipment, and generators. Technologies
available are:

        Gasoline engine -- used for smallest. Mucho fire code hassles.

        Diesel. The old-line standby. Fuel is much safer to store,
        but needs tending. The block must be kept heated in cold
        climates if you want it to start. All sizes - Cat makes
        'em as big as you want -- I've helped tend a pair of
        600kw units in a third world county....

        Gas Turbine. Not very fuel-efficient, but much less routine
        maint than Diesels. Also smaller.

variations:
        Propane fuel
        Natural Gas

All share the same hassles to some extent or another. They have to
be run, UNDER LOAD, an hour+ per month. They need the oil changed.
They need clean fuel; #2 Diesel tends to grow weird bugs that clog
the filters. The propane and natural gas can feed modified gasoline
piston engines and turbines. Some Diesels run on a fix of #2 and
gases. [The ultimate example -- a sewage plant will recover sewer
gas and use it w/Diesel. If your userbase is full of BS; or your
tie curls and your boss has 2 horns, you might go this route...] 
Natural gas has advantages of no storage hassles; propane does
not go stale.

In short, they all need tending. Regularly. 

As for installing, there are a million details. Ventilation. Fire
codes. Noise & Neighbors. Floor loading. Power transfer. Load
segregation [what is, and what's NOT, an emergency load...]
Hire an engineering fire with experience in your locale -- this
is not a task for anything less.

        
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