How many Kilowatts per month usage in your professional shop?

[Leo Graywacz]

This month electric usage for my shop was 772 kWh, a bit longer than a month, the meter was read for 33 day. Taking all fees, demands, transmission, taxes and whatever else they can think of....my price per kWh is 26.7 cents. My per kWh electrical generation charge is 7.7 cents. So 19 cents per kWh is what they charge me to get that power to me.

My service is 3 PH 208v wye

[Malcolm Schweizer]

Thanks Leo, that is good news- much less than I had feared. I checked out your site and love your work. I especially love the entryways!

[Leo Graywacz]

I'm just a single guy. I have 3PH power but most of my machines are single phase. The only 3PH motor in the shop is my spray room fan. Recently I put a 4 ton AC into my shop. Makes it a pleasure to be in there in the summer. It use to get past 90F everyday in the shop and I ran the spray room fan just to have the air movement. But moving 90F air is still hot air. What I have found is the AC draws just a bit more than the fan AND IT COOLS ME!! The 3PH fan draws the equivalent of 16.6 amps and my AC draws about 17.5 (single phase)

Typically my highest usage month is in the winter. And according to my bill, this year it was February. I don't have the number but it looks like 960 kWh/ I suspect that I was running both sides of my shop which means two propane heaters, lights for both sides plus my sprayroom lights. And of course that fan (3PH, 3HP 36")

Just curious. You said your electricity is 50 cents kWh. Is that the generation charge or is that the total (total price divided by kWh used) like I showed with my 26.6 cents per kWh?

Thanks for looking at the site.

[Malcolm Schweizer]

Leo, it is per Kwh, with the fuel surcharge being the biggest chunk of that. There is a small monthly service fee on top of the per Kwh charges. It is common to have a home electric bill of $500. If you use A/C it skyrockets. I am very frugal and also travel a lot so my bill is just shy of $400/month for the house with no A/C.

[Leo Graywacz]

Around here single phase is supplemented by businesses. There are a lot of charges on commercial 3PH accounts that most residential accounts don't see. The demand charge is one of them. This is a charge that is put on top of everything because you use the electricity that they provide to you

It is measured in 15 minute increments. In those 15 minute increments it measures your maximum continuous draw. And then they add that to your bill. Sweet huh?

I have a

Transmission Demand Charge....$6.59 kWh
Distribution Demand Charge......$6.06 kWh
CTA Demand Charge................$0.55 kWh

Those aren't on my total kWh's. They are on the Demand charge kWh calculation.

This months bill was based on 8.2 kWh So multiply that by those above numbers and add it to the bill. And there are more...

Distribution Customer Service charge. Fixed..$38.50
Distribution Charge per kWh........................$0.0178 (multiply by total kWh usage/month)
FMCC Delivery Charge................................$0.00981 (multiply by total kWh usage/month)
Comb Public Benefit Charge.........................$0.00433 (multiply by total kWh usage/month)
DOE Credit............................................ ...$-0.00206 (multiply by total kWh usage/month)

And of course 6.35% state sales tax. But they give you a $150 exemption so on my $206 bill I only pay taxes on $56

[Mark Bolton]

One gotcha on wind I saw get found out the hard way is to make sure you have speed limiters on the blades (i.e. can turn them out of the wind or a magnetic brake - preferably automatically) or they can end up landing quite a bit downwind when they spin up to fast. This probably wrecks the turbine as well

Well on small turbines any type of blade furling is pretty much out of the question due to the complexity. The way its commonly accomplished is to have the rotor axis shifted from the pivot/tail axis or angled to that pivot axis. This allows the rotor to rotate out of the wind as the wind speed increases which allows air to spill past the rotor as well as reducing the wind swept area therefore keeping the assembly safe. It would of course be foolish to construct even a small wind generator pointed squarely at the wind as any large storm or freak wind burst could easily destroy it. Small commercial generators achieve it through blade flexure. In high winds the composite blades actually bend which again reduces the wind swept area and of course the deforming from the bend reduces the rotors efficiency and spills air.

if you're lucky enough to be in a really high velocity wind area the cubing of power from the speed pays back. You also have to factor in some overhead for the system loss which starts to eat into the low end pretty quickly but is a smaller fraction of a larger system.

Agreed, which was my point that its all about up front costs and siting. Even in low wind areas if your siting is optimal and costs are low it can become more an more attractive. Sadly efficiency is often in the 35-45% range by the time you get to the point of use. But again, if the siting is optimal, it gets more attractive. For instance if your able to site at the top of a gradual up-slope where you gain the compression of the wind and so on. There are many factors but the main one is the home-brew. Without that your sunk.

I wouldnt think most, or Malcom for that matter, wouldnt consider doing this however its good information to get out there because it is in fact do-able especially if your in a area which sees 20mph winds or better on a reasonably consistent basis. Its why wind farms spend so much time siting. Of course an individual only has the property they own .

10'd system in a 10 mph area (which according to eyeballing weatherspark St Croix averages about that) for $1000 total cost installed your payback is in the ~2 year range, where I'm at its closer to 12 years. A 20'd system in comparable conditions cuts the payback by about 4x. I personally suspect that, for me at least, $1000 would be somewhat optimistic and I'd probably have to budget 2-3 times that for diy for the turbine/tower and then some more for control and conversion systems which are perhaps harder to do easily on the cheap (perhaps I just need to up my scavenging skills more ).

Again, its all about the siting. Global wind maps and "averages" are a starting point but if you've ever been to the beach and see all the kites flying, sloping sand dunes, and the like, it may be worth renting a data logging meter for a period to see what your site specific numbers actually are. They may be bad, they may be better than you think. Again, I dont think this is an option for Malcom but its fun to talk about and, for sure, more people should be playing around with stuff like this in my opinion.

With regards to the cost of building a home brew generator its of course up to the individual how far they want to go. You can build something that looks like Frankenstein but makes juice or you can build something that looks like it came out of a production facility that makes juice. You can take it to whatever level you choose but the cost of components that generally need to be purchased new (Wire, resins, fasteners, rectifier components, and so on) are well documented and a small portion of the cost. Of course then there the tower and associated wiring/components.

I never insinuated you could setup a wind "system" for 1K, but the generator could easily be done by someone handy with fabrication skills and equipment (read lots of bits and pieces laying around and good access to more), in a well equipped shop, for that excluding labor.

For commercial systems running 10-15k you're payback on the 10' runs more like 17-25 years and even the 20' is 4-6 (which isn't bad if you can swing a 20' windmill - pun intended).

No qualms there.

Hopefully one day we see very cost effective, small to mid sized, vertical shaft generators which could be placed on commercial roof tops but its all about getting the costs down and efficiency up a bit which will likely be a long time.

Im not a huge proponent of wind per-say either. I dont think its the answer to our energy problems because I dont think there is any single answer which is why we are always stymied on the subject. My perspective has always been you have to have a multi facted approach to the problem and you have to entertain, and use, all of the facets. We are going to need solar, wind, geo, coal, nuclear, nat. gas, all of it. But the corporate interests who want to line their pockets rather than work for the greater good AND make money wont let the multi-facted approach work.

A big anti-wind factor I think of is we are already finding on massive wind farms in the midwest that tampering with the global wind patterns will have many many unanticipated effects.

[Rich Enders]

Malcolm,

What about a self contained diesel generator? I see 30Kw units advertised for about US$10,000. Maybe someone here knows the economics, and I read that the new design diesels run cleaner than gasoline.