How to enter Fuel bills when there are multiple fuel types

[Gamaliel Lodge]

EDIT: OptiMiser now offers direct support for multiple fuel types.  On the Utilities tab, select “Multiple Fuels” in the Fuel Type control and then open the Multiple Fuel Entry popup. You can choose Start and End dates (preferably spanning at least one year) and then enter total usage for each fuel.  The instructions below are still useful, if you feel that you can accurately describe multiple periods of combined usage.

OptiMiser’s utility analysis currently handles only one Fuel type.   For multiple heating fuels, you can work around this limitation by converting usage for a second fuel to the same energy units as the primary fuel and combining the usages.  The tricky thing about doing this is that the delivery schedules will probably be different.  You will probably have to combine multiple bills to achieve a period with known total usage.  You may even need to combine all of them into one period covering the entire heating season.  It would be helpful to read the section on “delivered” fuels in the Utilities help for a better understanding of unusual periods.  Here are the Btu equivalents for a selection of heating fuels for use in conversions:

Natural Gas (MCF) – 1,025,000
Natural Gas (Therm) – 100,000
Natural Gas (MBtu) – 1,000,000
Electricity (kWh) – 3,412
Propane (CF) – 2,539
Propane (Gallon) – 91,330
Fuel Oil (Gallon) – 140,000
Wood (Cord) – 20,000,000
Wood (Pound) – 8,000
Pellets (Ton) – 16,500,000
Pellets (Pound) – 8,250
Kerosene (Gallon) – 135,000
Coal (Ton) – 28,000,000}

[Les Lazareck]

How would you handle if propane is used for water heating and wood is used for heating the house?

[Gamaliel Lodge]

I would not combine those for the utility analysis.  The most important function of the utility analysis is to calculate a weather normalized  heating and cooling usages.  Combining a base-load-only fuel with a heating fuel would just muddy the analysis for the heating fuel.  You can tally the annual propane usage yourself, check it against the DHW usage total in the model and then make appropriate calibration adjustments.  (You can view the DHW usage by clicking the “Report…” button, opening the “Energy Analysis” frame on the popup, and clicking the “Load Table” button.

You may also want to view this topic on modeling wood heaters:

[Carlos Espinoza]

If a home has already renewables installed, e.g. solar pv, is it best to determine what the monthly energy generation is and add it to the appropriate bill–assuming actual renewable bill data is unavailable for a 12 month cycle?

[Gamaliel Lodge]

That’s exactly right, Carlos.   And if you don’t have the generation data, then it is better not to enter the electric bills at all.  In complete usage data could have a very problematic impact on the utility analysis and model calibration.

[phillip mulligan]

I don’t see “multiple fuels” only “fuel” or “fuel and electric”
I can’t get the program to recognize the wood fuel I entered under other fuels

[Gamaliel Lodge]

The utility analysis automatically combines and analyzes all fuels entered in the main interface and on the Additional Fuels interface. However, they are not represented separately in most tables, graphs, and charts.

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