Are there any commercial wood-powered generators for emergency home use?

January 19, 2014 5:49 PM

We are planning to build a new home and would like to have a small generator around, just in case something goes wrong and we need to keep the essentials running for a while. The area has very good power supply, but since it's mostly hydroelectric, the increasing winter bitterness makes think that there might be some problems in the future (i.e. freezing), so we just want to have a few hours/days of independent capacity. Of course a small gas-powered generator will do the trick, but since we are in a wood rich area and everybody has always an abundance of wood around, we were looking at how to exploit this situation. We found several blueprints to build wood-powered generators and read a few articles, but it seems weirdo territory and usually there is a good reason why the mass market hasn't adopted a technology. But maybe our research skills are terrible and instead there exists a generator manufactured ans sold by a reputable company. Do you know of any?
posted by caudingo to Home & Garden (11 answers total)

They are just by their nature going to be more complicated as they need to be a boiler that creates steam that drives a turbine which turns the generator as compared to most back up generators where the engine drives a crankshaft which turns the generator.

This difference also means they are slower to react and not as well suited for emergency back up.

Also cold weather isn't really a problem for hydro facilities so much as reduced precipitation.
posted by JPD at 6:14 PM on January 19, 2014

Best answer: Well, there are small wood stoves that generate enough power to charge a cellphone through the use of a thermal electric generator, but anything wood-fired that had power output on par with even a small gas powered generator would probably be either a steam engine of some sort, or an wood-gas powered internal combustion engine. I wouldn't put either one in the same class of a small gasoline motor in terms of ease of use, safety or required maintenance.
posted by Good Brain at 6:16 PM on January 19, 2014

A project affiliated with Dean Kamen, the Segway and water purification guy, recently announced a (non-emergency) home generator system that works off of a combination of solar power and a natural gas / Stirling engine^ component.

In previous coverage of his work on Stirling engines he described wanting to design something for developing world use that would generate electricity from the heat of a small cooking stove, though I think on that scale it was just going to be able to do something like charge a cell phone as Good Brain describes.
posted by XMLicious at 6:46 PM on January 19, 2014

Why not a wood stove for heat and a small gas generator for electricity? Wood stoves are a great secondary heat source whether or not the power is out. And backup generators generally can't be run without supervision, i.e., while you are sleeping.
posted by Sukey Says at 7:04 PM on January 19, 2014

you could try to convert a gasoline, natural gas, or propane powered generator to use wood gas. FEMA has a PDF on how to do this in an emergency, but I've never tried it, so I don't know how well it works.

on a re-read, it seems like you already found this. I did see this video last year though, which shows (me anyway) that wood gasification can work for something like this.
posted by ArgentCorvid at 8:06 PM on January 19, 2014

The energy in hydrocarbons is much more accessible in a four-stroke motor than in a heat+boiler system. A wood-fueled generator is going to be lossy, and a pain in the ass to manage. Really, use wood for warmth and gasoline for electricity, as JPD and Suky Says.
posted by anadem at 8:16 PM on January 19, 2014

For a 'just in case' scenario, a common or garden petrol (or diesel) powered generator is a no brainer.

Get a good quality one - when you want it to start, it NEEDS to start. Don't even think about the china specials, get a name branded one.
posted by GeeEmm at 11:12 PM on January 19, 2014

Ensuring that it reliably starts when the emergency occurs has even more to do with performing regular maintenance and upkeep on your generator. It's not a bad idea to have a power inverter of this sort for a vehicle on hand as your backup's backup, since people tend to maintain their car or truck better than a generator sitting in a shed somewhere and they'll start even if the generator has been neglected.
posted by XMLicious at 12:02 AM on January 20, 2014

Best answer: I am relieved to see the answer you are getting is no.
Spark ignition engines can be run on wood gas, but the gas is filthy, filthy with solid particulate , moisture and tars. This concept is only for the hobbyist who would be quite happy to tear the engine down and do a valve and ring job after every use.
The steam Rankine cycle is out of the question for the home environment.

So, that out of the way, you really should be heating with wood, if for no other reason, a wood stove keeps working when the power is out...
posted by Abinadab at 8:28 AM on January 20, 2014

What is your heating/cooking fuel source? if it's piped natural gas or LP, there are generators available commercially (i.e. at big-box home improvement stores like Home Depot or Lowe's) that will test themselves monthly, and automatically start when the power goes out. Not quite as convenient with LP, as you have to have a tank big enough to hold the fuel for it as well as for your heating and cooking.
posted by ArgentCorvid at 9:01 AM on January 20, 2014

but the gas is filthy, filthy with solid particulate , moisture and tars

Only if you don't do it right.

Biomass gasification is a viable option for running a generator. It's not very widespread as yet, as it's less convenient than pouring in a liquid fuel, and most people don't have access to suitable quantities of biomass. Plus you need to take into account the cost of a suitable gasifier.
posted by HiroProtagonist at 8:30 PM on January 20, 2014