My weekend cottage is powerless at moment, but running the lines to attach it to ‘the grid’ is estimated to cost $16,000 ! I am approx. 300 yards away from nearest power box. So instead of doing grid tie solar, I am now contemplating off grid solar and looking at generators for backup.
Sounds like diesel is the way to go for reliability and low maintenance, which is my biggest goal. I am willing to pay a little more for this.
My question is, what do you think of running Biodiesel in most modern diesel generators? Is this feasible? Is this for summer time only? (I live in northern Wisconsin, and wonder if Biodiesel mixes would freeze!).
I’m trying to be as ‘earth friendly’ as possible.
Thanks!
Mark
Mark:
Being totally off-grid is not as easy as you think unless you have lots of solar modules and batteries, and really limit the use or quantity of larger appliances. Having said that, depending on your solar exposure and location, the more solar you have the less generator run time so fuel type may not be a big issue.
Some diesel engine manufacturers will void their warranty if you use bio-diesel, although this is changing as manufacturers get more experience with bio and the quality of the fuel processing improves. However, not only bio-diesel, but regular diesel fuels can be a real problem during the winter unless you use crank case heaters, fuel pre-heaters, and other heating devices to prevent the fuel from turning into gel. If you think solar is expensive just to run a few appliances and lights in an off-grid home, wait and see what it will cost you in batteries and solar modules just to power a crank case heater on a diesel generator all winter !
This is why many backup generators are propane. The fuel does not go stale, it does not freeze, and you don’t have to worry about it turning into a semi-solid in the fuel lines. A fill up once a year to a 500 gallon underground tank should not only give you many months of backup power, but can also be used in a gas stove since you will not be able to have an electric stove in an off-grid home.
I am currently building a house, and read your article on generators used with a battery/inverter system to provide off grid power. This intrigued me.
My question is whether or not it is better to get an LP powered generator, versus a diesel because of the price of fuel. The price difference in my area is almost $2.00 per G. I realize that diesel motors usually have greater longevity than other types, but Guardian has introduced an 1800 rpm liquid cooled 18KW generator, and I’m wondering if that might not be more cost effective.
I would also appreciate any info you could provide that would allow my builder to do the install correctly for a future battery /inverter system.
Thank you.
Sincerely,
Mike Jamison
Mike:
My selection of generator type has to do with how often it will be running each week, month, or year. For example, if I want a generator for backup power for a home on the grid that only suffers a power outage for a few hours or days each year, I would select a propane generator as the fuel (propane) does not go stale or get old, so it can sit in the tank for years until needed. Of course you should run the generator every few weeks to keep everything lubricated and operational.
If I was designing an off-grid solar home and the solar system was large enough that the generator would only be needed to run a few hours each week, I would also select the propane fueled generator for the same reason.
If I was designing an off-grid system that needed a generator to run many hours each week I would select the diesel generator as the fuel costs will be lower and would also allow making my own bio-diesel if needed. Since this generator would go through a fuel tank much faster than an occasional use generator, there is less chance that the diesel fuel would go old. Of course you can add additives to the diesel to make it store better, but most of these additives are expensive and another thing to take care of.
If the home’s location is not accessible for filling the propane tank with a propane delivery service truck, you may have to select the diesel, as it will be easier to deliver the diesel fuel in 5 gallon hand-carried fuel cans.
As you see, all designs are have trade-offs and there is not always a perfect answer.
I have an oil burning (#2 diesel) furnace installed in the mid “80s”. Can I use bio diesel. My tank is inside.
Jeff Yakobics
Jeff:
The answer is yes, under certain conditions. Straight biodiesel burns a little hotter than #2 fuel oil, and has a higher cetane rating. But biodiesel will turn to a gel before regular diesel fuels do. Biodiesel fuels also form more deposits and have more solids than diesel fuel, and require replacing filters more often. Biodiesel also has a corrosive effect on some types of rubber hoses and seals, which is why some diesel engines have problems and others do not, depending on the type of seal material used.
If you still want to do this, I suggest using a “blended” biodiesel fuel that is usually 20% biodiesel mixed with regular diesel fuel. Most suppliers also add special “solvents” that reduce this filter clogging problem. If this lower mix fuel works out you can try a higher percentage mixture of biodiesel.
I read your “overview” on bio diesel kits and the general process. I think it was important for you to mention the necessity of finding sources of waste vegetable oil before one were to begin his or her own processing station. However, I wonder with the escalating prices of crude oil if the interest in bio diesel will become more prevalent for people interested in defraying the cost of home heating oil, and or diesel for their vehicles. With this being said is there a possibility for myself to secure waste vegetable oil sources only to find a hidden market evolves, and find others who want to make bio diesel like me become competition only to outbid me for the waste vegetable oil at my sources? The basis of this inquiry is to ask if I could skip the middle man and buy virgin vegetable oil in bulk to process for bio diesel?
Eric Brown
Eric:
I mentioned at the close of this article that as the price of diesel fuel goes higher and higher, more and more people will be trying to take the “free” waste oil from the same fast food outlets and this could be a problem.
In larger cities with lots of restaurants, I think you will soon see the existing waste management trucks hauling this waste oil away to their own central storage tanks where they will start selling this back to people wanting to do what you are doing. In smaller cities and rural areas, until the demand exceeds the supply, I think there will be room for each bio-diesel maker to stake out their own specific restaurant without fighting over it with others.
However, I think you will find that buying any virgin oils to make bio-diesel will cost as much as buying diesel at the pumps. In the end, the small bio-diesel users will still make their own from waste oils that are free, and the larger users will be buying waste oils from a bulk waste management company at much lower costs than buying new un-used oils of any type.
