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Can I enter negative values for energy consumption? Follow

Usually, but not always. In the majority of cases, a negative meter is a sub-meter from your main grid electric meter, used to exclude parking, cell towers, or purchased electricity that may be distributed to another building on your campus. In all of these cases, you can just enter a meter with negative values for each month.

However, if you are using a negative meter to capture energy that you produced on site, it is not as simple. A basic example would be using a gas boiler to produce steam, and then measuring steam distributed to the building next door. In this case your boiler takes gas as an input, but the thing you distribute is steam. If the thing you purchase (gas) differs from the thing you want to subtract (steam) then you need to perform additional calculations before you subtract anything.

Special calculations are required if you are subtracting energy produced on site by any of the following:

  • Boiler
  • Chiller
  • CHP Plant
  • Onsite Solar or Wind

In these cases, you cannot simply enter negative values read directly from the outgoing meter. Rather, you need to follow the instructions in the table below to ensure that you correctly account for the conversion of energy. For more detailed information and specific examples about why these calculations are necessary, please refer to the Technical Reference for Negative Energy Consumption.

Whenever you enter a meter with a negative value, you will be asked to indicate the reason for the negative value(s). The following table shows the reasons you can select, and whether or not negative meter entries are appropriate for your situation.

Negative Consumption Justification Option

Can I enter negative meter readings

directly into Portfolio Manager?

My utility bill shows negative values.

Yes. But we recommend you double-check with your utility to find out why the value is negative. This could happen if a utility estimates earlier readings and later corrects/fixes your values.

I am subtracting energy that I purchased from a utility (such as grid electricity). I am subtracting either:

  • Energy being sent to another building
  • Energy being used for part of my property that I want to exclude (e.g., cell tower or parking garage)

Yes. Negative values may be entered directly off your outgoing sub-meter.

If you are excluding part of your property, see this FAQ for more information.

I am subtracting energy that I produced at my property (such as steam from a boiler). I am subtracting either:

  • Energy being sent to another building
  • Energy being used for part of my property that I want to exclude (e.g., cell tower or parking garage)

Only after performing additional calculations. Use the  Negative Energy Consumption Calculator (linked below) to help you perform the required calculations.

If you are excluding part of your property, see this FAQ for more information.

I am subtracting solar or wind energy generated at my property.

No. We offer a special column in onsite Solar and Wind meters, where you can enter information about exports to the grid or to other properties. You may want to consult the Technical Reference on Green Power.

Other

It Depends. Contact customer support (Click on "Ask A Question" above) with a detailed description of your situation, and we’ll let you know what to do.

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