Economics of diesel generator vs. building-in power upgrade?

My shop has two separate 100 amp panels which aren't adequate for peak intermittent demand of our machines. Working with our electrician to cost-out upgrading both panels to 200 amps; his best estimate is about $15k. The upgrade involves new larger conduit and wires, new panels, new disconnects, labor to run new conduit and cable through several other suites between us and electric room, and an engineer to get plans ready for permitting process. And I'm sure other incidentals not yet listed. All that of course stays with the landlord and building once we leave the leased space. If we had a lot of job orders lined up, we probably wouldn't sweat that kind of money, but we have to sweat it. When we have a detailed written estimate we'll approach the landlord/building owner about cost-sharing but for now let's assume I'll have to pay it all out-of-pocket.

I can buy a used 80 kva diesel generator with under 10k hours for about $5k. Plus $$$ for long cables to reach from parking lot to machines inside. Plus some for disconnects/panels, etc. But trailer-mounted generator goes with us when the lease ends.

I don't know offhand what the fuel consumption rate is, anyone? We'd need to run the generator about 15-20 hrs/week about 35 weeks/year = approx. 700 hrs/year.

Has anyone been there/done that? Advice?

In general, it makes the electric co look cheap.

Any generator you are interested in should have fuel consumption figures available. You can look it up. Yes, it is load dependent, but they "eat" even when just idling.

They come with noise issues, exhaust stink issues, etc. etc.

Might be cheaper to break the lease and get a space that suits you.

5 seconds on google gave me this chart; Blog :: Diesel Generator Fuel Consumption Chart in Litres

When I do the conversion I get an average estimated consumption of 2-5.5 gal an hour. No idea of accuracy.

I don't know what your electric rates are like in VA but here in CA I know more and more farmers who are using generators to power irrigation pumps. Between rates that are twice as high as the rest of the country and the cost of bringing power to new wells generators are becoming a familiar sight. Most are propane powered rather than diesel.

Its going to cost far more per KW/Hr for the diesel. If it was cheap everyone would do it. Also keep in mind that all the infrastructure you need within the building for the generator still says with the building. Depending on the region there are all sorts of zoning and building codes about the location of generators and their fuel storage. That's something you need to take in to account up front.

Hold the phone and your thoughts....

We managed a fleet of trailer mounted units from 25 KW to 45 KW and fuel consumption is not too bad if engines are well maintained and not old...but...

Noise and fumes are a problem.

We had "whisper watt" units that were less noise than a stock F250 diesel and had current emission requirements for ca but you still get folks complaining when running.

We would state no genny no phones and they would leave us alone...but...
Depending on where you are at there may be all kinds of permitting issues.


And the hp of the engine matters....Our fixed units were chevy v8 on lpg and only 35 KW.

They were permitted at 35 hp as someone messed up then we had to convince folks that the v8 was less than 50 hp....That a pain in the rear!
Look at Appleton for the connector to connect the genny to your building and invest in a suitable transfer switch as the mains need a break before make interface that cannot be altered so you heavy loads need to be on seperate switched panel.

Having the generator plug in is less of a hassle than a hard wired one.

Also make sure the hitch can be removed and it is chained down as we had a 45 KW dragged off without the hitch.

25 kw maybe 1 gal per hour and 45 kw maybe 2 but it depends on the load.

Use 1 gal per hour for unloaded consumption or check with the manufacturer as the consumption chart is usually a requirement for some permitting agencies.

Bottom line is check first with building department to see if you can install an " emergency backup generator", then if good check with air resources or other agency if exists (call companies that advertise in phone book and ask about permits) , check with insurance carrier as well.

Yes we are going long but better to look under rocks first.

We had everything permitted 5 ways to Sunday with a young fleet but then a new rule regarding containment required all units to be double tanked or a retention area where they were parked.

Last check your lease....

Neighbors and city planners dislike generators....

Good luck and provide updates.

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Thanks, now that noise and fumes are mentioned, I'm guessing one or both will kill the diesel option for us. Using propane would I think get rid of the fumes issue, but add a propane storage issue unless one forklift-tankful would run it for a few hours. I always thought we'd connect the generator directly to our hungriest machine or two (with appropriate disconnects etc.) and not bother the building's electrical system. So as of now I'm going to look only at relatively quiet. propane-powered generators.

+1 on what Tony said.

Loma Preita quake, telco emergency use my own last "big one", but rule of thumb for #2 diesel is one gallon per hour per each 10 KVA of actual load. EG: 100 KVA, 85% + loaded, steady 10 gallons per hour meals.

I harbour a 10 KVA MEP-803a "tactical quiet". Because I can afford it as a toy. Not because I SHOULD have it.

And it ain't all that noisy. Until one loads the Mike Foxtrot!


Upgraded electrical may be cheaper than moving house, tough numbers or no.

If not? Move, don't generate. Or move only the work if it is a minority issue.

Gen sets WERE a primo part of Day Job for me at one time.

It is not part of your Day Job now, and you should not want it to become so.

Instead of replacing your panels install a new 400 amp panel and sub feed your existing panels. Then add new sub panels where and when you need them. With a bit of design effort you should be able to minimize conduit and wire.

2¢

Allot of the backup gensets I see are Natural gas, not propane.

I've got an older Onan with a Ford 300-6 single phase, natural gas, sitting in the shed right now,
but I think my well might not have enough flow to keep it happy.

City supply should be big enough, might need a regulator change though.

Adwcali said:

I don't know what your electric rates are like in VA but here in CA I know more and more farmers who are using generators to power irrigation pumps. Between rates that are twice as high as the rest of the country and the cost of bringing power to new wells generators are becoming a familiar sight. Most are propane powered rather than diesel.

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Unless you are with a co-op in California (I moved from there to Virginia) average power rates in Va are 1/3 or less of what they are in Cali for a high end user. In California most providers have a tiered system where the more you use the higher you pay per KWH. My power company here actually has a high user plan that makes the price cheaper, the exact opposite of Cali.

digger doug said:

Allot of the backup gensets I see are Natural gas, not propane.

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Per therm/BTU/HP/KVA, the more competitive market has put Propane cheaper, many places, most years. Any decent-sized load on a gen set makes it not so simple.

If the tank isn't large enough, draw chills it too much to sustain the demand.

I've got an older Onan with a Ford 300-6 single phase, natural gas, sitting in the shed right now, but I think my well might not have enough flow to keep it happy.

City supply should be big enough, might need a regulator change though.

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Must be 15 years since we shed the larger farm, closer to 30 on the smaller one adjacent, Lewis County, WBGVA. Five wells, around $800/month @ 1/8th of production royalties, plus a LARGE ration of "free gas", each of of the two.

Any one of them - typically 1500 PSIG "rock pressure", with more than enough flow.

Most folk don't have THAT!

Nor do I, long since..

Neighbors can get stupid real fast,especially if they think your getting something they are not.
they will complain about noise ,fumes ,wires in parking lot. All stupid stuff that wont make your life any easier plus they will call every governing authority to make your life miserable.

Monarchist said:

Per therm/BTU/HP/KVA, the more competitive market has put Propane cheaper, many places, most years. Any decent-sized load on a gen set makes it not so simple.

If the tank isn't large enough, draw chills it too much to sustain the demand.



Must be 15 years since we shed the larger farm, closer to 30 on the smaller one adjacent, Lewis County, WBGVA. Five wells, around $800/month @ 1/8th of production royalties, plus a LARGE ration of "free gas", each of of the two.

Any one of them - typically 1500 PSIG "rock pressure", with more than enough flow.

Most folk don't have THAT!

Nor do I, long since..

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1500 psi don't really mean much on a well.

When welltender comes 'round, watch pressure drop as he blows it down,
and how fast it recovers.

BTW the "normal" contract around here is 200k cubic feet per year free...rest you pay
"well head price".

Propane is running just under $1.00 a gallon here in larger loads (3000 gallons to farmer
down the road).

But Gas is pretty cheap due to Marcellus coming on line too.

digger doug said:

But Gas is pretty cheap due to Marcellus coming on line too.

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Still holding 'several' thousand shares of EQT though.
Plastics feedstock plants are just over the horizon. Bigtime.

Monarchist said:

Still holding 'several' thousand shares of EQT though.
Plastics feedstock plants are just over the horizon. Bigtime.

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Yup, the shell ethylene cracker is being built on the old
"St. Joe lead" grounds. (Monaca on the Ohio, where route
60 crosses overhead)
Pipelines are being run to it as we type.

digger doug said:

BTW the "normal" contract around here is 200k cubic feet per year free...rest you pay
"well head price".

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And "well head" was cheap, too. Older "sands", earlier years, we also got 'casing head' gasoline, 1912 onward, ran vehicles and tractors on it. Bit of Pennsylvania grade crude was another byproduct, and was good enough 'raw' for lots of needs on a working farm.

We were 'on deck' when that change from unlimited to a (rather generous) cap kicked-in.

We had frugal habits. Also right-decent insulation YEARS before it was common, so it easily covered house and garage-shop heat, 'early start' greenhouse, gas cookers, gas A/C, gas clothes dryer, gas hot water, SEVERAL gas fridge/freezers (Six, IIRC. Had been dairying..) . Electric power outages, we even still had the pre-1953 plumbing and fixtures for gas lights, Wellsbach mantle. Good lighting, actually. Just a bit sooty above, given time.

An Uncle who had for years been using his front door (open or shut) as a wintertime thermostat finally ceased being quite so profligate. Once the cap came he left that tasking to Honeywell like other folks.

WHHJR said:

Instead of replacing your panels install a new 400 amp panel and sub feed your existing panels. Then add new sub panels where and when you need them. With a bit of design effort you should be able to minimize conduit and wire.

2¢

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Thanks, am now looking seriously at similar solutions. My electrician points out that existing conduit to my panels is only 1 1/2 inch and will have to be replaced by at least 2" to get any fatter wires thru it, and there's maybe 180 feet of conduit from building electric dist room to our panels.

Anyway my latest harebrained idea has me offering to pay small elect bill of next-door-neighbor biz. If he lets me borrow some current. He has 100 amps and only uses about 10 amps for a few ceiling lights when he's there a couple hours a day. I'll put a 100 amp breaker in his panel, run my 4-wire #2 cu encased in 1 1/4" liquid-tite flex conduit up wall, thru existing hole in wall, down to a new empty panel I have, and that separate 208/3 would feed only certain machines. That'd be worth enough to me that if paying his Elect. Bill isn't enough I'll introduce him to Ben Franklin and his brothers.

Cannonmn said:

Thanks, am now looking seriously at similar solutions. My electrician points out that existing conduit to my panels is only 1 1/2 inch and will have to be replaced by at least 2" to get any fatter wires thru it, and there's maybe 180 feet of conduit from building electric dist room to our panels.

Anyway my latest harebrained idea has me offering to pay small elect bill of next-door-neighbor biz. If he lets me borrow some current. He has 100 amps and only uses about 10 amps for a few ceiling lights when he's there a couple hours a day. I'll put a 100 amp breaker in his panel, run my 4-wire #2 cu encased in 1 1/4" liquid-tite flex conduit up wall, thru existing hole in wall, down to a new empty panel I have, and that separate 208/3 would feed only certain machines. That'd be worth enough to me that if paying his Elect. Bill isn't enough I'll introduce him to Ben Franklin and his brothers.

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*sigh* Don't DO off-the-wall-clever of that sort in a public forum. Your lawyer can explain why.

The "better thing to do" is to take over his whole lease. Then use it. Even upgrade BOTH premises. And/or rent it back to him on favourable terms. Far better than feeding gen sets, that - however fueled.

Leasing for expansion, then renting out until it happens is bog-standard growth-management 101, anyway.

You'd not BE in this fix had you but planned that way, previous go.

An Organization That Doesn’t Plan Its Future Isn’t Likely to Have One

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An Organization That Doesn't Plan Its Future... | Strategic Futures(R)

Plenty of of other sources. Plenty of good examples. Most bad examples don't leave a lot of tracks. Wiser to avoid their examples than have to ponder on them.

What I am seeing, frankly, is all sorts of "long way around the barn" solutions to a problem that does not need to exist at all.

I have not yet, that I recall, seen a real explanation of how the equipment you already have (and had when you rented the space) is too much for the electric service you have. Did you actually list the stuff that would all be "on" at once, at least according to its electric requirements? AND show the actual capability of he service? I think you have spelled out the service capability, and maybe the other as well, but it seems it has been spread out in in lumpty-bump different threads. Definitely not here.

Maybe some details would be good... all in one place. A pair of 100A panels is not tiny, althoug I can see it being exceeded. As 3 phase 208, it is 72 kVA, equivalent to 72 HP of motors, or a mix of motors and lighting. Even at the 80% rule, that is almost 60 HP continuous all day power.

Some adjustment of timing, etc, seems as if it ought to be cheaper than any of the various "solutions". Unless you have one big machine, it seems you should be able to manage to avoid running all the high draw stuff at once. And that is if it really is over 57 HP of continuous operation machines plus lights.

Possibly you are making some inaccurate assumptions about how the power draw adds up, or the like?

Then also, you seem not to have the orders yet.... so you likely have even more flexibility as to when you run things. There are 24 hours in the day, not just 8. Use them. It's not even overtime if you establish a regular second shift

I have seen clients get all tooled up to do great things in high volume, when they had no orders, and then, as a result, run out of money and be unable to actually do ANYTHING. My suggestion is not to add to their number.