21-0512 Emergency Power Backup System: Natural Gas on a Campus

Question

For emergency power, Swarthmore College is installing a new natural gas backup power system to replace the existing diesel generator at the DCCP building and potentially other diesel generators serving buildings on campus. The new backup generator will be sized to provide power to the entire campus, including the Swarthmore DCCP pursuing Petal Certification. This narrative is included to satisfy Exception I06-E6 4/2010 Emergency Power Systems for LBC v3.1. Every effort has been made to ensure the natural gas backup power system operates only under emergency conditions, such as loss of power to the campus, and has been sized to meet campus requirements. The campus requires this backup system for the following reasons:

1.     It will allow the campus to function during frequent power interruptions and unstable power supply.

2.     More than 95% of students live on campus, thus disruptions to the power supply impede education but also present a danger to health, safety, and welfare of the student body.

3.     On-going scientific experimentation on campus requires steady and consistent power supply.

Due to these campus-level needs, and the increased efficiency of a campus-wide natural gas backup system compared to individual generators, we are proposing an exception to eliminate the battery backup for 10% of the DCCP’s lighting load per Energy Petal Imperative 06 – Net Positive Energy. The DCCP provides essential health & safety services, as a majority of students reside on campus and the building requires full power at all times to ensure food services are available to students, a health and safety mandate. Therefor providing a portion of backup power is impractical to the needs and function of the building during a power outage.

The natural gas system is necessary as it is functionally and economically infeasible to provide campus backup power using a battery system, given current technological limits, energy storage limitations, and battery system costs. The gas backup power system will result in the removal of an existing diesel backup generator for the dining facility, and potentially other diesel generators serving other buildings. The natural gas backup system will not impact adjacent properties with noxious emissions or noise, due to its central location on campus (see attached Swarthmore Map), and the intermittent nature of its use.

To satisfy emergency lighting system resilience, the emergency lighting will be powered through 4 inverters on the project. The capacity of the backup system is sized to accommodate the needs of the entire campus. The backup system will use existing natural gas infrastructure; No new natural gas service will be provided. 

The DCCP project will not use this gas generator to meet its net-zero energy goals. A new MV Switchgear with metering capability at the feeder level will be installed on the DCCP project so energy from the natural gas plant can be measured and excluded from the 12 month performance period.

Campus Map

Answer

The project team may apply Exception EC-016 Critical Infrastructure and Life Safety - Emergency Power as the project provides essential health and safety services for the campus. The language of the exception has been updated as indicated in italics below:

EC-016 Critical Infrastructure and Life Safety – Emergency Power

Critical infrastructure projects or projects in which emergency power is a life safety issue (e.g., hospitals, fire stations, transportation depots) may use combustion for emergency backup power, if the backup power needs cannot reasonably be met by batteries.

If combustion must be used, propane generators are preferred; diesel or natural gas backup generators are allowed only in situations where propane backup generators are unable to provide the functionality necessary to the facility, have a significant negative impact due to danger, or have a significant negative environmental impact.

In all cases, combustion-based backup generators may only be used if the generator:

  • Is not included in the project’s strategy for typical operation and any use during the 12-month performance period is offset through the project’s renewable energy generation; and
  • Does not impact adjacent properties through noxious emissions or noise.

If storage tanks for emergency power pose a negative impact due to significant danger related to density or other factors (e.g., projects located in Transects L5 or L6), the project team may include a hard-piped natural gas service to the emergency power system, if the gas service:

  • Is not connected to the project’s primary building energy systems;
  • Is sized exclusively for the emergency power system; and
  • Includes a dedicated utility meter to account for any emergency use during the 12-month performance period.

The project team must describe their efforts to minimize the amount of backup power required and must submit to the Dialogue for preapproval to use this Exception.

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