Cost of generation

David G · Dec 9, 2013

I have seen several posts questioning the economics of electricity generation.

I did some calculations, and welcome feedback.

Assumptions:

Tractor size 50HP = 37.5KW
Fuel Consumption = 2 GPH
Fuel Price = $4.00 / gallon.

2 GPH * $4.00 price per gallon / 37. 5 KWh = $.21 dollars per KWh

I think 2 GPH is pretty conservative.

Anonymous-0 · Dec 9, 2013

beats the heck out of nuthin , but , how much does the local remc co op charge when you are getting power off the grid

lpgasonly · Dec 9, 2013

That's fine if you use every bit of that 37.5kw.
Did you figure other costs of running that tractor? oil and filters? overhaul when it is worn out? Running it out of fuel? rebuilding the generator and the list goes on. Just plug me in to the pole man.

David G · Dec 9, 2013

Mine is about $.11 per KWh

David G · Dec 9, 2013

Nope, just the consumables

Cas · Dec 9, 2013

One problem I see using this method is assuming that 37.5 kw is used. What if the demand is say 10 or 15kw at times. Wouldn't that double or triple cost.
On the other side, when my electric is out and we run our generator I am not too concerned with the cost of production.
ps: If you look at different fuel/kw charts for larger generators 7 gal of diesel per 100kw seems to be a constant. That is for an engine generator unit. BD had an interesting comment earlier about kw of energy used for gear to gear
heat produced. I can not remember the amount used.

tomturkey · Dec 9, 2013

Looks pretty cheap when the ice takes out the grid. Food in the freezer stays frozen and you stay tasty warm reading a book by the lamp. We've come along way from Rural Electification Act. Delco generators and oil lamps. gobble

David G · Dec 9, 2013

That raises it to $.28, probably more realistic on fuel consumption.

Bob · Dec 9, 2013

You're a little off. It basically takes 2 engine HP per KW generated, (due to efficiency losses) so you'd need a 75HP tractor to generate a steady 37.5 KW.

Figuring a GOOD, efficient tractor that gets 17 HP hours per gallon, you would burn 4.4 gallons per hour.

4.4 gallons X $4 = $17.60 per hour / 37.5 = 46.9 cents per KWH!!!!!
Virginia Co op Extension

RayP(MI) · Dec 9, 2013

My little 4000 watt/8 hp burns a little less than a gallon of gasoline per hour, but we work it pretty hard to keep furnace, two freezers, a refrigerator (or two), and a 3/4hp pump going - (not all at the same time). I figure my electric supplier is a bargain compared to running emergency generator. But has saved my bacon enough times to be worth it. Ever consider the price of loosing a freezer full of food?

mkirsch · Dec 9, 2013

I think the discussion is more about, "How much would it cost to generate your own electricity using a tractor?"

massey333 · Dec 9, 2013

lpgas,I guess I'am getting old and don't do new math,but the units are paid for and don't eat any thing setting so the only cost is fuel when running,so it is cheap insurance.I have 3 diesel powered systems,1=100hrs.yr,1=30-50 hrs,1=10-20hrs.,but few times(yrs.) 1-2 weeks non stop,so they pay,not cost.The best part is when neighbors that won't give you the time of day otherwise and make fun of you for owning such a expensive idem becomes your best buddy.(Sarcasm)

Lou from Wi. · Dec 9, 2013

WE never figured the cost of running our 5500wt generator. I installed a panel box in the garage that is hooked to our 200amp main house panel box. We have had to call on the generator several times to run the house current ,less the elect range, water heater dryer and high current usage appliances. Only thing we did was take off the small fuel tank and add a 10 gal flat top tank. We built a cart to move it outside (or near the service door) when it is necessary to run it, when we suffer from power outages.The longest it has run was 8 hrs when the storm hit a couple years back.Wouldn't think of using a generator for whole house operation ,unless we lived in a remote location and no power company available to service our home. Generators are swell in most circumstances ,and I'm happy with ours. LOU.

Texasmark1 · Dec 9, 2013

Ha! Numbers seem realistic to me. We pay 11cents to our coop too.

Reason for my answer is we have a few rednecks around here. Two got mad at the coop and pulled their meters. Been without electricity of any kind for 30 years....stupid? Yessssss.

Other ones gen their own and don't care what it costs as they are full blown rednecks and they are going to do what they want regardless......stupid? Yesssss.

But tell them that.

Mark

IH2444 · Dec 9, 2013

(quoted from post at 00:47:52 12/10/13) I have seen several posts questioning the economics of electricity generation.

I did some calculations, and welcome feedback.

Assumptions:

Tractor size 50HP = 37.5KW
Fuel Consumption = 2 GPH
Fuel Price = $4.00 / gallon.

2 GPH * $4.00 price per gallon / 37. 5 KWh = $.21 dollars per KWh

I think 2 GPH is pretty conservative.

Yep but if you keep it going 24 hrs that is 48 GPD!

ouch....

Brian Jasper co. Ia · Dec 9, 2013

You"re off by quite a bit. We have had 3 36 hour ice storm outages in the past 7 years I"ve lived here. My 5000 watt portable with a 9hp OHV Briggs burned about 8 gallons per day. That"s with just a couple CFL lights, the gas furnace, fridge, and TV. No washer/dryer. My electric bill is usually about $90, so in 3-4 days on the generator I"d spend in fuel what I do in a month of high line service. You"re not going to run a 75hp tractor 24hrs on only 8 gal of fuel.
This summer I installed a 12K standby unit that runs on LP. I"m kinda curious to see if we can tell the usage on the LP bill.

Tony in Mass. · Dec 9, 2013

2 years ago in the Halloween ice storm, the oil drain unscrewed from the 4KW gen, first hour of first day. If it didn't die, it would have used 1&1/2 to 2 gallons an hour at best. Improvise! Rewired the furnace burner into an extension cord, and another line to the fridge and floor lamp in the kitchen, out the hatchway into a window of an old caravan, 1KW inverter plugged in the cigarette lighter. Not constant running, but house stayed warm, food stayed cold, 4 days, 7 gallons. Number crunchers on here said it was technically impossible, but I don't care, pulled it off once, all ready to do it again next time. Another small inverter in a car kept the phone and credit card machine going at the shop.. so the only hot food in town for people with an electric range. The 440 for the freezers? Agh... well.. whatever was getting soft, was going to be the special of the day!! .. don't even want to think about keeping 3 phase going with gasoline or diesel... pray for 20th century civilization to return quickly....

Geo-TH,In · Dec 9, 2013

My 3500 w RV genny is suppose to use 4 gallons in 12 hours, 1gal/3hrs, producing half out, 1750w. I only use my genny to run a 4 hp chainsaw. It seems to run forever on very little gas. However, the chainsaw only runs a little at time.

So rounding numbers that's 1 gallon for 5kw-hr.

If gas is $3/gal then making electricity with gas is 5 times more expensive. I have IR propane heater for backup heat. If I have a prolonged power outage, I plan to use genny to run ref, toaster, coffee pot, hot plate and well. May only use genny when needed.

I have 30 gallons of gas standing buy and 5 20# tanks of propane. If needed I could take gas from tractor gas tanks.

George

MarkB_MI · Dec 10, 2013

One thing to remember is you won't be drawing anywhere near 38 kilowatts, but the tractor will still be using quite a bit of gas just to spin the generator. Gasoline engines are very inefficient at low power settings due to throttling losses; diesel engines are better but still need heavy loads for maximum efficiency.

I think our house is typical: gas baseboard heat, gas water heater and stovetop; everything else is electric including ductless air conditioning, oven, freezer and three (don't ask!) refrigerators. Our electric bill averaged 32 kW-hrs per day last year. So that's an average consumption of 1.3 kW.

I'm going to assume you need a lot more power since you bought a 38 kVA generator. Let's say you average around 4 kW. If you're producing 4 kW at 2 gph, your cost is a whopping $1.60 per kilowatt-hour. And that's just the cost of fuel; there's also maintenance and depreciation on the tractor and generator, which can be significant if both are new but you don't use them much.

Bret4207 · Dec 10, 2013

(quoted from post at 17:07:33 12/09/13) Ha! Numbers seem realistic to me. We pay 11cents to our coop too.

Reason for my answer is we have a few rednecks around here. Two got mad at the coop and pulled their meters. Been without electricity of any kind for 30 years....stupid? Yessssss.

Other ones gen their own and don't care what it costs as they are full blown rednecks and they are going to do what they want regardless......stupid? Yesssss.

But tell them that.

Mark

I don't follow you. If someone makes a choice to disconnect from mainline and do without or make their own, why is it stupid? It's a choice. I pay about $350.00 a month for power. I'd love to be able to shut it off!

Texasmark1 · Dec 10, 2013

My remarks were based upon my personal experiences in power
generation, or lack thereof during bad weather when the power
goes down.

Yes they are personal choices, and the decisions of the owners,
but they are stupid choices if you ask me, and nobody did!

But some people carry their stubborness too far (opinion again
and we all have one just like other things.......) That's the
definition of Redneck down here. They are going to do what they
want regardless "Dam the Torpedo's, Full Speed
Ahead"....(Admiral David Glasgow Farragut, battle of Mobile
(Alabama) Bay, US civil war.)

Mark

ss55 · Dec 10, 2013

If you know how to get 25 Horsepower-Hours out of a gallon of diesel fuel and also know how to get over 100 percent energy conversion from a generator you should patent those ideas.

I agree that your actual fuel cost per KW-Hr will be around four times that high.

Pair-a-dice farm · Dec 10, 2013

(quoted from post at 14:47:52 12/09/13) I have seen several posts questioning the economics of electricity generation.

I did some calculations, and welcome feedback.

Assumptions:

Tractor size 50HP = 37.5KW
Fuel Consumption = 2 GPH
Fuel Price = $4.00 / gallon.

2 GPH * $4.00 price per gallon / 37. 5 KWh = $.21 dollars per KWh

I think 2 GPH is pretty conservative.

In some cases 2GPH might be right but my 4630 52hp Ford won't use but about 1 1/2 GPH pulling a 9' disc mower. My chicken house generator was a 130HP deutz 125kw and at the most it used was 3GPH in the summer with 40 4' exhaust fans, 8 cool cells running all the time and feed lines part time. The other costs are probably pretty close.

RodinNS · Dec 10, 2013

To start with you won't make more than 25 KVA from that 50 hp tractor and when you do you'll burn more like 3 gph... so you run more like $0.48/KVA... and that's assuming full load amps. In reality you might run at 50-60% of load most of the time which would put you in the 15 KVA range and still probably in the 2 gph range... so you're then looking at more like $0.53-0.55 KVA. Then factor in your other costs it's easily double to three times as much...

Rod

johndeerefan · Dec 10, 2013

Boy these prices make my electric rate seem cheap. Our electric rate is $0.07 per KW.

The LP house generators will drink about 1 gallon per hour. Hope you have a big tank if you plan to run it very long.

Bob · Dec 10, 2013

At 3 GPH, your Deutz was only using about 50 of it"s 135HP!

Pair-a-dice farm · Dec 10, 2013

(quoted from post at 20:55:50 12/10/13) At 3 GPH, your Deutz was only using about 50 of it"s 135HP!

That may be so but that's what it used and that is actual measured consumption, running a minimum of 40 5hp motors, and 200 60 watt light bulbs as well as the 8 cool cell pumps.

Cost of generation

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Similar threads