Switching to Bio Fuel

A Few Tips if You’re Switching to Bio-Fuel

I remember as a kid my mom’s old Nash Rambler station wagon and stopping at the filling station to get gas. The best time was late after school in winter when darkness was setting in and the lights on the gas pumps were switched on. Now if you’re old enough to be an AARP member like myself you probably remember the glass domes on top of the gas pumps that were illuminated with a light bulb on the inside and advertised the brand and type of gas. I can still see the Sinclair Dino Regular, Supreme and Diesel signs and the Tydol Flying A sign. Masterpieces. It wasn’t until I was a teenager when my first memory of fuel prices sunk in, around 14 cents a gallon for fuel oil and gasoline was in the low 20-cent range. As the saying goes “those days are gone and never will be again”. The current cost of energy produced by fossil fuels continues to rise with fuel costs and let’s be realistic, it’s never going to drop and yes I’m one of those people that believe we will run out of this resource in the near future. Alternate energy sources and the goal of a “net zero” building must be a priority for our researchers. But even with these folks going all ahead full, I believe our dependency on fossil fuels is going to remain for the next 10 to 20 years. Emissions from fossil fuel plants are also in the limelight and are believed to be contributing to global warming. For these reasons reduced dependency on fossil fuels is inevitable.

For us folks in the heating industry, natural gas and fuel oil remain in center stage as an energy source for commercial and industrial buildings. Owners are faced with rising fuel costs and many are looking for alternative fuels that they can use with their existing equipment. Many are also aware of the emissions problems and are taking proactive steps to reduce them. For those folks using # 2 heating oil, Bio-diesel has come into play. Bio-diesel is a diesel-like fuel, which is completely miscible with diesel or # 2 heating oil. I’m sure most of you have read about this type of fuel in the papers and we are seeing some facilities that are currently using # 2 oil making the switch. Now there are different grades of bio-fuel available ranging from B5 to B100 and the numbers correspond to the blend ratios. The good folks out at Brookhaven National Laboratory have done considerable research with these fuels and here is some data from their findings:


  • Oxygenated by – 10% by weight
  • 8% – 10% higher density
  • About 10% lower heating value
  • Very low sulfur and nitrogen content.


  • B100 has a strong solvency effect
  • B20 is not a substitute for tank cleaning
  • Copper systems can experience accelerated degradation and sludge with B100
  • Biocides effective with # 2 oil should work with bio-fuels
  • Storage in general for 6 months recommended similar to # 2 oil


  • At the B20 level, bio-diesel is very compatible with oil fired heating systems and provides positive emissions results.
  • Long term, large scale storage implications do not seem to be a large concern.
  • At higher concentrations low sulfur is a premium benefit but there are oil pump and pour point concerns.
  • Bio-fuel properties match well with the technology trends in the industry.

Now some folks we know have switched over to B5 and B15. The following information is from feedback we have been getting from technicians at various facilities that have switched over to a bio-fuel mix. There seems to have been changes in the operation and performance of the burner systems. Expect to see oil pump pressures changes which effects the fuel supply rate to the oil nozzle and return pressure changes if the burner is using a bypass nozzle. As a result air / fuel ratio settings are affected and there have been reported instances where it caused fouling of the heat exchanger. Considering the bio-fuel has a higher density and a lower heating value, these observations and conditions are possible. Now this doesn’t mean if you switch to bio-fuel the burner performance will be an issue, it simply indicates that the burner equipment needs to be checked and re-adjusted when the change is made. In the instances where fouling occurred, the burners were never re-adjusted until after it became a problem. The lesson here is if you’re going to make the change to bio-fuel, be prepared to have the equipment checked and re-adjusted. This may need to be done several times (with each fill up) if your introducing the bio-fuel gradually into a large tank that has to mix with some standard # 2 oil.

Having a few checks and tests of the burner system throughout the year is good idea anyway. I believe the rising cost of energy is going to force a change in the frequency of equipment service on fossil fuel burning devices and it’s likely that the annual tune-up will become a semiannual or even quarterly occurrence in the future.

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