Putting biofuel in an electric generator to sell back energy to power companies?

[Genecks]

Hey,

 

Lately I've been wondering if it would be profitable for a person to start making biofuel in their back yard, throw it into an electricity generator, and then pour that back toward the electric power companies. Would this be a profitable venture?

[CaptainPanic]

Hey,

 

Lately I've been wondering if it would be profitable for a person to start making biofuel in their back yard, throw it into an electricity generator, and then pour that back toward the electric power companies. Would this be a profitable venture?

Generally, fuel is more expensive in terms of money/energy than electricity from the net.

Making your own fuel might solve that, but you have to get a cheap installation.

 

I know that some farmers have a bio-gas installation, connected to a gas engine. They might use the waste heat (and the CO2!!) for their greenhouses, and sell the electricity if they have a surplus. This seems profitable. However, they typically have 2 MW (electric) installations. That is a little large for your backyard. Also, it must be said that most greenhouse farmers just use natural gas in their combined heat and power installations. (Here's an article about Dutch farmers doing this at quite a large scale). So, in summary, it is interesting for farmers because they can use all the products they make: electricity, heat and CO2.

 

Similarly, there are installations called micro-chp. It's an electricity generator that sends the waste heat to the heating system of your house, and sends any surplus of electricity back into the net. I don't see why that wouldn't run on bio-gas.

 

An even smaller scale will suffer from the economy of scale (bigger = better, so smaller = worse)... and there will be a point where it's all just a waste of money.

 

But before shooting down your idea too early - what fuel were you thinking of? Ethanol, biodiesel, bio-gas (methane), pyrolysis oil, something else? And would you have access to some freebies (i.e. do you have an engine and an electricity generator lying around)?

 

Btw, I think that at this moment, solar panels might be your best option. They're relatively cheap at the moment due to an overcapacity in production. That's bad for the industry, but good for consumers like you. Depending on where you live (depending on the electricity price, and how much sunshine you get), I read that they're now economically interesting without subsidies. But this might be considered a thread hijack. Sorry.

[Genecks]

Gas of interest: Biodiesel.

 

Alright, fair argument. Yes, the economics of scale would come into play. I would want to make a fair ROI within three years. But if biodiesel would work well enough, I could at least generate electricity for a house. Assume I have a backyard of 25 ft x 25 ft.

 

Yeah, I came about this idea from looking at gasoline vs. diesel prices. Cost for production of biodiesel. Efficiency of biodiesel. And then I put together ideas and considered how to make it profitable for the individual (since selling homemade biodiesel can be difficult).

 

Seems practical if a person has the money and time: I consider the time factor to be the most available thing to an individual pursuing this idea for profit.

Edited August 30, 2012 by Genecks

[Phi for All]

You might need to check with your local utility about what kind of equipment they allow for renewable energy credits. Most are required to allow things like solar and windmills to feed electricity back to the grid, but I hear they can be sticky about the details.

 

Keep us posted on this, please. I know there are people who have been very pleased with their investments in micro-energy production. I remember reading about a guy who had rooftop solar that powered his home and made him an extra $3K/year from his utility. He was out of pocket around $12K after his state paid for most of the costs (2-3 times what he had to pay out, iirc). Couple that with a couple of fully electric cars and that's my idea of heaven on Earth.

[CaptainPanic]

Gas of interest: Biodiesel.

 

Alright, fair argument. Yes, the economics of scale would come into play. I would want to make a fair ROI within three years. But if biodiesel would work well enough, I could at least generate electricity for a house. Assume I have a backyard of 25 ft x 25 ft.

 

Yeah, I came about this idea from looking at gasoline vs. diesel prices. Cost for production of biodiesel. Efficiency of biodiesel. And then I put together ideas and considered how to make it profitable for the individual (since selling homemade biodiesel can be difficult).

 

Seems practical if a person has the money and time: I consider the time factor to be the most available thing to an individual pursuing this idea for profit.

 

Just a back-of-the-envelope calculation:

 

A liter (which is 0.8 kg) of some cheap vegetable oil costs maybe 50 cent (euro cent) for a regular consumer. That means 50 cents for about 800 grams of oil, which contains about 40 MJ/kg of energy. That means that your oil costs about 1.6 cent/MJ.

 

Electricity costs about 10 cents / kWh, or about 2.8 cents/MJ. Prices may vary depending on your location.

Gas costs about 60 cents/m3, or about 1.8 cents/MJ. Again, prices may vary depending on where you live.

 

The bottom line is: you'll need dirt cheap vegetable oil to compete with electricity or gas from the standard networks. Your investment should be low, and your maintenance/cleaning on that equipment should be simple and cheap, or you will never make any money. And you should minimize any additional operating costs if you have any.

 

Finally, please note that biodiesel is not very sustainable. It is a primary food source that you turn into energy. Its production has a large carbon footprint (a lot of energy was used in cultivation, fertilizer, transport, to name a few).

 

So, unless you happen to have access to oil that would otherwise go to waste, I do not think this is either economic or good for our environment.

 

(Please note that I am a great fan of sustainable energy, but local home production really limits the options and it is important to be realistic about that).

 

[edit] Large industrial players are able to compete because of 2 reasons: subsidies, and the economy of scale (for investments, bulk transport and bulk purchase of the oil).

[Genecks]

The reason I consider time to be the factor that makes this worthwhile is because a person with a lot of time can go find the resources to turn into biodiesel. From there, the person can start feeding it into a generator and sell back energy to the power company.

 

Thanks for the calculations.

Edited August 31, 2012 by Genecks

[Enthalpy]

Efficiency improves if you use the motor's waste heat for your own home.

 

Some farmers run their engines on home-made biodiesel to save money, without subsidies for it, despite they wouldn't pay taxes on normal Diesel oil, so the economic comparison must shift a lot under certain circumstances. It also tells that farmers don't consume much carbon-emitting energy to produce biodiesel - to the least, they can use biodiesel in this first step a well, and need less than the produced biodiesel.