15-1110 v3.X Reduction of DES Associated Energy

Question:

While undergoing our 12 month monitoring period, the project team have discovered that a significant portion of reported electricity use for the building is attributed to pump use that is owned by the District Energy utility that the building ties into. This pump is activated when there is surplus solar energy generated onsite that can be fed back into the DES. This pump is used by the DES to supply the surplus solar energy to other buildings connected to the utility and does not form part of the building’s energy usage. The pump is not directly metered, yet data is available from the DES that reports duration of use. We therefore propose the following methodology to subtract this energy from the buildings energy reporting: Calculate electrical consumption when in use and multiply its consumption per hour by reported hours of operation for each month. This figure is then subtracted from the total metered building energy consumption to provide true energy consumption per month.

Answer:

When energy systems that are not part of the LBC project are connected to the LBC energy meter, the team may delete the non-project energy from their production requirements. In this case, the project should provide the exact DES's energy consumption from the utility provider, or a third party tracking system. This figure may then be subtracted from the total metered building energy consumption to provide true energy consumption per month.

Calculating the DES's electrical consumption by estimating use per hour and multiplying by hours of reported operation per month is not sufficiently accurate to assess energy load data. If a “per hour” calculation is necessary due to lack of consistent data from the performance period, the team will need to get hard numbers of the amount of energy historically used by the pump per hour, verify the range of variation, if any, and provide an accurate, conservative, estimate. The methodology and calculations to omit the non-project DES energy must both be addressed in I06-1 Energy Narrative.


Post ID 3347

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