Generating Electricity from Natural Gas at Home

Hello mschultz

Unless you have your own personal Natural gas well at your own home, and that Natural Gas is thus totally free of cost to you, No.

The costs involved in the process of Natural Gas arrival at your premises, the inefficiencies of the local heat-engine, coupled with the other losses, would be far greater than purchasing your electricity from the local distribution Network owner.

Energy transmission via Electrical transmission, is far more efficient than gas reticulation, when all relevant costs are taken into account.

Of course, as an emergency generating system, for your own use, your idea is quite often used, even by local Electrical Utilities.

Kind Regards....

So, your saying the cost energy wise to push the natural Gas through the pipeline is so much more expensive than pushing the same amount of energy through the electric grid? How much more efficient is the distribution of electric energy? If I have a gas heater vs an electric heater, I can have the gas piped directly to me to run my gas heater or the energy company can use gas to generate electricity that comes to me to run my electric heater. Which is more efficient? Which is cheaper?

Hello again mschultz

<"....Which is cheaper?....">

Already stated, in my above Post

Summary:

The total costs involved in Gas reticulation, far exceed the same amount of energy sent via Electrical Distribution Networks.

Remember that gas reticulation is often "helped along" by heavy subsidies, and may on the surface appear cheaper, often by the complex subsidies which are concealed in the data and financial maze of Gas Companies and their associates.

Kind Regards....

What the real cost (not including subsides) of gas distribution other than the electricity for the pumps to keep it under pressure. Could the grid encompass the entire USA in theory? Or is there a limit to the length of pipe used in a natural gas grid?

Dear mschultz,

Ignore the cost differences in transmitting gas and electricity.

In your case the cost to generate your own electricity from your gas supply will have greater influence.

Do some simple calculations;

What is your cost of electricity ?

What is your cost of gas ?

What is the efficiency of your gas/electricity generator ?

As a simple example, use this data to determine the cost for running say a 2kW heater via the power company electricity for 1 hour and then the cost for running the same heater from your gas-driven electricty generator.

For completeness, add 1)the cost of your generator and 2) the power company to disconnect you from the supply network.

Yes, a great deal of the energy content of the gas is lost in the conversion. In fact its even less than the "half" you stated. Utilities are very effecient and I would be supprised if theirs was over 35%. Transporting the gas is a low tech way to get it to your home but since the utility buys and burns millions of BTUs more than you ever would they have the advantage of getting a much lower price than you could.

Answering your question: Would it be cheaper for me to have my own natural gas generator in my basement to generate my own electricity?

Based upon your cost of gas and your much lower efficiency of conversion than the utility (you would be at around 25%) Absolutely not. Good for an emergency generator though.

OK I got it. Thank you. Could I shift the focus a bit? I can purchase one therm at base rate for $1.91. My power company pays 1.54/therm.(according to my bill) that leaves 1.91-1.54 =37 cents for transport + other expenses + profit. One therm equivalent is 29.3 KWh which cost me $3.19 at base rate. So, if the power company spends 1.54/therm to generate electricity at 35% efficiency (29.3/2)= 10.3 KWh and sells me the electricity at 11 cents/KWh leaving a return of $1.13. That would leave 1.13-1.54= -11 cents loss/10.3KWh. Now, of course, that is the bottom tier rate, which may be subsidized by the higher tier rates. What's has got me puzzled is this. Wouldn't the power company make more money selling natural gas as gas, rather than making electricity with gas? What am I missing here?

My utility is Pacific Gas and Electric. In other words the gas company is the electric company. My new question is this: Given the inefficiencies of converting natural gas into electricity wouldn't PG&E make more money selling natural gas as gas, rather than making electricity with gas? Sorry if I have not made myself clear and thank you for all your responses.

Yes, it is entirely possible that PG&E makes a higher profit on their gas business than their electric business. They are a public utility and you can read their annual report here http://www.pgecorp.com/investors/pdfs/2006AnnualReport.pdf. It's 184 pages long and I don't have time to slog through all of it (but check out the guy in the stainless steel suit hanging from the helicopter on page 23). Looking at the big numbers on page 60, for 2006 electric revenue was $8,752,000,000 and the cost for that electricity was $2,922,000,000. that is a markup of 300%. Of course that doesn't include operations costs which they do not split up between electric and gas. They bundle those costs together. On the gas side they received $3,787,000,000 and spent $2,097,000,000. The markup there was only 181%. Electric appears to be more profitable for them. Of course this is a sledgehammer appoach to the problem but it's 6 AM and I'm getting ready for work right now :).

Overall, they are limited to an ROE of 11.35% combined so they have some room to juggle the profits between electric and gas. They also do not always generate all of their own electricity. They buy and sell across the grid just like everyone else. They also invest revenue in short term securities and get some revenue out of that. You may have better luck digging your true costs and profits out of this report, but as they say in school, that is an exercise left up to the student.

It is often cheaper to generate you own electricity with natural gas, about 3 - 4 USD cents per kW/h, however one must do a total life cycle cost analysis for cost of fuel, cost of the machinery, maintenance, inconvenience factor, noise, you will need a transfer switch to use the mains as a backup, etc. Probably not worth it for the 10 kW size you need for a small home. I've been in the generator business for 34 years and do not have one at my home. I could even build one that works from kitchen and garden garbage, total heat recovery, etc and it is still too much work just to save a few hundred USD per year.

It's all very confusing. In the UK, gas companies can supply electricity and telephone services, and electricity companies can sell gas. It will all end in tears.

I know of a local plastics manufacturer that has several gas turbine generators at his facility. He calculates the cost of the gas versus the cost of the electricity and buys gas futures accordingly. He only runs the gas turbines when the price is right.

Of course heating plastic sucks up a large amount of power so he is able to use all the electricity he can produce.

I do not know if he has paid back the costs of the turbines in money saved yet. He does have a 250kW wind turbine that he expects to have paid off in 7 years.

Those are the kinds of capital outlays you have to expect with this kind of installation. If you're up for it do the math for your area and the answer will become obvious.

"Natural gas is used to power generators to create electricity. ... Would it be cheaper for me to have my own natural gas generator in my basement to generate my own electricity?"

I'm not sure that just making electricity for an individual residence, by itself, be would economically viable.

However, consider that the exhaust and cooling system MUST "eliminate" about 60% of the energy (NG) consumed as heat that could be used for domestic hot water (and residence heating in colder environments). There are also heat driven refrigeration systems (even air conditioning).

I believe Fiat was selling a NG ICE gen-set in the past that included heat recovery. That might have been as far back as Oil Embargo of the 1970s.

Keep in mind that large commercial gas turbines are probably about 40% to 60% efficient if I remember correctly.

There is also the technology of "micro turbines" ... but I have no knowledge of its' capabilities.

Would you consider buying enough stock in your (or another ) electric utility company so that the dividends pay your electric bill?For $6K-10K maybe, you could have your own automatic, maintainence-free electrical supply system. You could easily spend that much for your own generator, and still have to fuel it and maintain it.

I don't know too much about power plants, but how would you actually use the natural gas in your home to generate electricity? Doesn't it come into your home at inches of water pressure?

large commercial gas turbines are probably about 40% to 60% efficient

Sorry but these big turbines are only that efficient if they are "Combined Cycle". That is they use the exhaust heat to make steam and either use that in a low grade steam turbine or sell the steam to an adjacent plant (or use it themselves) thereby adding that efficiency to the turbines. I don't think I have ever seen any that were actually 60%...

You could use the exhaust heat yourself but consider there is a lot more infrastructure for you to maintain. if you are good at mechanicals and electricty and refrigeration, then it could approach the cost of buying but the life cycle costs of each portion of the infrastructure (Hot water preheater, refrigeration, and of course the generator itself) should be used. Bottom line, its much easier (and more reliable) to use the utility's economies of scale and just buy the electricity you need from them.

Here in GA, gas is about $1.19 per therm (100,000 btu) which makes it about 1/3 the price of gasoline -- fairly cheap. Electricity is about 10 per kWh, also pretty cheap. If I installed a cogeneration unit that would generate electricity and supply domestic hot water I could get the combination at about 85% efficiency, much better than the electric company does. (This scenario relies on being able to use all the domestic hot water efficiently.) (Cogeneration units like this are sold by Climate Energy Systems.) So, out of 100,000 btu (for which I would pay $1.19), I'd get 85,000 BTU of useful electricity and heat. This is equivalent to about 24 kilowatt hours (for which I would pay $2.40)

Not a bad deal.

Thank you Ken for the good lead. Commins make a natural gas generator also, but Honda looks very interesting.