How can a Dual Fuel Boiler System Benefit Your Building?

Hospitals, schools, factories, retirement homes, and other large buildings nearly always have redundant boilers—each fully capable of providing all heat needed during the coldest of winter days.  That engineered redundancy is a sensible and reliable way to make sure the chill of New England winters stays outside where it belongs.

Facilities with redundant boilers typically burn just one fuel: natural gas, propane, or fuel oil. In most rural areas there are just two choices: oil or propane.

Some smart facilities managers have set up their boilers to burn two different fuels. In such cases, the purchasing department can watch the fuel markets and buy whichever fuel is less costly per delivered BTU, and therein lies the first benefit of using two different fuels to heat your building.

Fluctuating Fuel Prices

Year after year, the price per gallon of oil and propane has fluctuated, sometimes wildly, as when the “polar vortex” struck New England in 2017 and the cost of natural gas tripled in one day and the spot cost of fuel oil grew almost as much. If you are not prepared, these kinds of rapid fuel price changes can quickly cause havoc in annual budgets.

Up north, most high schools consume between 25,000 and 200,000 gallons of fuel oil each year (or the equivalent in gas). Private school and college campuses can use as much as 500,000 gallons of oil each year or more. With that scale, a one-dollar change in price per gallon can make a big impact, so having a second fuel option can be a budget saver.

Biomass Fuel Offers More Stable Pricing

Finding a fuel with low, stable pricing has been an elusive goal of most facilities and financial managers. In recent years urban operations switched to lower-cost natural gas. But rural schools and commercial buildings have not had the option of a fuel with a more stable, lower price.

That is until now, with the broad availability of modern biomass boiler systems.

Biomass in the form of dried wood chips are the new low-cost fuel option—especially where a second fuel (dual fuel) is desired.

The latest generation of high efficiency, fully automatic biomass boiler systems, combined with cost-reducing state rebates and Thermal RECs, have made a conversion to biomass a very smart move.

With those incentives, dried wood chips can cost the same as buying #2 fuel oil for just 80 cents a gallon.  Wood pellets net out at $1.40 a gallon while green wood chips cost the same as buying oil at just 50 cents a gallon.  And these are steady, stable prices.

Let’s compare using dollars per million BTU delivered (MMBTU) with Thermal RECs applied at $16 each.

  • Oil at $2.50 a gallon is $22.52/MMBTU
  • Propane at $1.25 a gallon is $16.34/MMBTU
  • Wood Pellets at $240 a ton is $12.09/MMBTU
  • Natural Gas at $1.00 a therm is $9.00/MMBTU
  • Dried Wood Chips at $120 a ton is $5.69/MMBTU
  • Green Wood Chips at $75 a ton is $4.37/MMBTU

Nearly all biomass boiler conversions are dual-fuel installations. In most projects the biomass boiler provides at least 90% of the winter’s heat, leaving just 10% for the fossil fuel boiler. Usually, an older oil or gas boiler is left in place for peaking and back-up duties.

Conversion to biomass boilers may seem costly but the extra upfront costs are soon erased by significant ongoing fuel cost savings.

Three common forms of biomass

Wood Pellets

Wood pellets are the driest, most flexible, easiest to manage and most energy-dense biomass option available. They flow like water and are easily blown from a bulk delivery truck into storage. Bulk delivery of wood pellets is now available in most areas of New England.

Precision Dried Wood Chips (PDCs)

Precision Dried Wood Chips (PDCs) are green wood chips that have been dried to a moisture content of 25% and screened so none are much bigger than a two-inch square. They cost a third less than wood pellets and are easier to store and manage than green wood chips.

Green Wood Chips

Green wood chips are made by chipping trees. Because they’re freshly cut, they can contain up to 50% moisture. Green wood chips are the least costly biomass option, but require boilers and heavy material handling systems specifically designed for this unrefined fuel.

The latest generation of high-efficiency biomass boilers are fully automatic, self-cleaning, and have low emissions—engineered for installation at schools, hospitals, nursing homes, factories, and other commercial properties.

District heating systems where a central boiler system sends heat out to multiple buildings on a campus make tremendous sense. Some are set up as cogeneration systems that make heat as well as electricity. These developments have caused many facility managers to look seriously at biomass fuel and boilers.

Benefits of Dual Fuel

Biomass is renewable and carbon neutral. Biomass fuel can save money while reducing greenhouse gas emissions. It’s readily available and far cheaper than oil. And for peace of mind, biomass fuel pricing is stable, not victim to the whims of the market. With its extreme economy, Biomass turns the tables on oil and propane by putting them merely in a back-up role in a dual fuel installation.

Today, biomass fuels supply about one-seventh of the world’s primary energy. That’s equivalent to approximately 1 billion tons of oil annually. If you have a boiler that will need replacement soon, or if you’ve been considering a dual fuel approach, contact us to learn more about biomass boilers and fuel.

Thermal RECs Explained: Added Value for Heating with Biomass
5 Important Reasons that Biomass Fuel is Better than Oil
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