19-0311 Emergency Generator on Campus

Question
Based on the XXXXXX building type, the National Fire Prevention Association (NFPA) code (which applies through the National Electrical Code) requires the building to have an emergency electrical supply, to power the elevators return to ground in the event of fire/disaster/emergency response, and for fire fighters to operate the elevators, even when the main electrical power is out.

XXXXXX is part of a larger campus energy system. This system places the heating, cooling, utility electrical connections, thermal storage, and emergency electrical generation in one common facility, providing energy
services to the whole campus. While the main services in this system (ie heating and cooling) are combustion free and all electric, the campus emergency electrical generation is planned to be a natural gas powered
generator. Natural gas is planned because:

- It does not have a flammable fuel tank (such as propane or diesel) and thus safer in this high density urban setting
- It does not have the air quality impacts of diesel

Having a single campus emergency generator rather than building by building has numerous benefits, including:

- Lower net construction and maintenance costs
- More powerful/responsive units in terms of startup time and peaking power
- More thoughtful placement of generator from a noise, air quality, and safety standpoint rather than numerous dispersed units

The campus emergency generator will be sized to provide backup power not only for code-mandated emergency requirements, but potentially additional demands in the event of a power outage.

Within the campus, only XXXXXX is currently planned to be certified as Zero Energy. Exception 18-0326 v3.1/Emergency Power System indicates that where propane is determined to not be feasible due to safety concerns, natural gas is an acceptable alternative, but that the serving infrastructure needs to be sized for emergency uses only. In the case of the XXXXXX campus generator, it will be sized to be somewhat larger than solely code mandated emergency electrical use. To meet the intent and spirit of this Exception, however, the project team proposes that for XXXXXX, the emergency electrical circuit serving XXXXXX from the campus
generator would be limited in wire sizing and service circuiting to providing power only to those emergency systems mandated by code.

Is this an acceptable approach?

Response 
For Zero Energy Certification, which has no back-up energy requirement, a combustion-based emergency generator, including a campus wide generator, may provide electricity to support emergency systems. I06-E6 Emergency Power Systems may be documented in this instance.
The project team must provide a narrative explaining the need for backup power, particularly with regard  to the project’s size and function, and describing what efforts were made to reduce the size of the system and prevent its use. Because the DES has not yet been built, it is also recommended that the team advocate for a non-combustion based emergency system to set the campus on a more sustainable long term path.
Note that if the project were targeting Energy Petal (vs. Zero Energy) certification, the project would need to use I06-E6 4/2010 Emergency Power Systems, as amended in Dialogue post " 18-0326 v3.1/Emergency Power System Approval Request" and sufficient battery backup would be required to supply the equivalent of 10% of lighting for a week, at minimum, before combustion based backup would be allowed. 
Documentation
All projects using emergency power generation:   
  • Exception Narrative

Projects with a hard piped LPG system must also include: 

  • Metering Data 
  • Technical Documents  (addressing pipe sizing)
Further Resources 
Given the recommendation to advocate to the campus planners to reconsider a combustion based system, ILFI is providing links to the following resources for more information to support that advocacy: 
Reducing GHG emissions by 2030 requires efficiency, adoption of renewables, and a transition away from fossil fuels in electricity generation. 2030 is 11 years away - less than the useful life of many fossil-fueled assets. Capital projects that expand fossil fuel consuming infrastructure will generally face failing to achieve emission reduction goals, or paying for early retirement of the asset. 

“The Paris Agreement sets the ambitious goal of limiting global warming to well below 2°C while pursuing efforts to limit the increase to 1.5°C. According to the Intergovernmental Panel on Climate Change, if we are to limit warming to 1.5°C we will need to lower our CO2 emissions by about 45% by 2030 (compared to 2010 levels). Even limiting global warming to 2°C will require nothing less than transitioning to a carbon-neutral economy by the middle of this century – only several decades from now.” - UNFCC

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