TECHNICAL ARTICLES

BACKUP POWER GENERATOR FOR INDOOR CULTIVATION

WHY A BACKUP POWER GENERATOR SYSTEM?

An indoor cultivation business owner asks his facility manager, “How could this happen?” Their crop is dying after a storm takes out power in a large area and makes roads difficult to travel. There was no backup power generator or emergency power plan in place.

WHAT IS EMERGENCY POWER?

Emergency power is power generation equipment intended to supply power to the facility when the normal electrical supply is interrupted. This equipment is usually a diesel or natural gas fueled combustion engine. The National Electrical Code (NEC) classifies systems as either emergency, legally required standby, and optional standby.

Emergency

Emergency power systems normally only refers to egress lighting, exit signs, and emergency alarm systems. These small loads are commonly supplied by batteries integral with the units. Emergency systems must be reenergized within 10 seconds of a power outage.

Legally Required Standby

Legally required standby is power mandated by sections of the building codes such as elevators and smoke control systems. Legally Required Standby systems must be reenergized within 60 seconds of a power outage.

Optional Standby

Optional Standby is what should be the most interest to cultivation facilities, it is what will keep your crops alive. Anything you want to supply power to that is not an emergency system or a legally required standby system should be part of the optional standby system.

EMERGENCY POWER EQUIPMENT

A backup power generator supplies power when normal power is interrupted. The type of generator will depend on the size of the electrical load it is designed to handle. Fuel Storage or Fuel Supply may be a natural gas line for generators that are 150kW and smaller. Larger generators are usually diesel with a base fuel tank but may have larger on-site storage tanks. The Automatic Transfer Switch (ATS) monitors normal power and automatically starts the generator and transfers to generator power upon loss of normal power. Generator Connection Cabinet Provides a quick, safe and permanent connection point for a rental generator.

WHAT SYSTEMS SHOULD BE ON A BACKUP POWER GENERATOR IN AN EMERGENCY?

Backup power is like insurance. The higher the value of the crop, the more provisions one should take to maintain power to critical systems. The real decisions facing the Controlled Environment Agriculture (CEA) designer is what systems to put on emergency generator power. Ideally, the entire CEA facility will have emergency power available, but that is rarely the case. At a bare minimum the following systems should be provided with permanent backup generator power:

• Control Power
• Communication and Security System
• Minimal Access Lighting
• Irrigation Systems
• Passive and Reduced Active Ventilation

Systems that are nice to have but you can usually operate for a short period of time without ill effects.

• Passive and Active Ventilation
• Air – Movement Fans
• Heating Systems
• Shade Screen Systems and Blackout Curtains

Longer term outages will typically require

• Cultivation Process Lighting
• Refrigeration and Air-Conditioning

High value crops may even justify a backup for the backup system so you are ready should there be a power outage while the first generator is being maintained or is out of service. If the budget does not justify a complete solution, loads can be reduced and segregated in their order of importance and function to minimize generator loading and cost. Controls, either manual or automatic, can be in place to supply the available emergency power where it is needed most at any given time.

ABOUT THE AUTHOR

John Chapman, PE, LC, LEED AP, M. Arch

John is Registered Professional Engineer who provides power and control consulting services for indoor cultivators in the United States. John is also lighting certified (LC) and an award-winning lighting system designer.

CONTACT US

E-mail: [email protected]
Ph: +1 (513) 609 – 4577