How Many Hours Can You Operate Your Emergency Generator?

Have you ever lost power and needed an emergency or backup generator to continue operations? Do you have an emergency generator on-site, or do you have a plan to find one when a situation arises? Today we will review environmental considerations when using emergency generators, and tomorrow we’ll take a look at safety tips for workers who use portable generators.

Many facilities use a backup or emergency generator to continue operations in case power is lost. The U.S. Environmental Protection Agency (EPA) regulates reciprocating internal combustion engines (RICE) in emergency generators. The extent of regulation depends on whether the emergency generator is new or existing, if the generator is a major source of hazardous air pollutants (HAPs) or an area source, and the size of the engine—that is, if it is greater than or less than 500 horsepower.

All emergency generators must follow some general requirements including:

• Using low or ultra-low sulfur diesel fuel
• Keeping within the maximum hours of operation—usually less than 100 hours a year
• Conducting performance tests and tune-ups and keeping those records

This article will discuss hours of operation for existing stationary engines (i.e., you commenced construction or reconstruction of the stationary RICE before June 12, 2006) in emergency generators at residential, institutional, or commercial area sources at that are not obligated to be available more than 15 hours per year (hr/yr) for emergency demand response and are not used for local reliability.

First, What Is an Area Source?

Area sources are smaller sources of HAPs that emit less than 10 tons per year (tpy) of a single air toxic or less than 25 tpy of a combination of air toxics. The EPA has discretion over whether to regulate categories of these sources. Most area source emissions are small, but the collective volume can be hazardous in densely developed areas where large numbers of such facilities are packed tightly into urban neighborhoods and industrial areas.

How Long Can You Operate Your Emergency Generator?

If you are an area source of HAPs and you are not required to have your emergency generator available more than 15 hr/yr for emergency demand response or do not use it for local reliability, the engine must meet the emergency engine operational requirements found at 40 CFR 63 subpart ZZZZ (aka, the RICE rule). In terms of hours of operation, these requirements can be unlimited, up to 100 hr/yr and within that maximum, up to 50 hr/yr.

Here’s the breakdown:

You have unlimited use of these emergency generators for real emergencies, such as power outages, fires, and floods.

You may operate the emergency generator for up to 100 hr/yr for any combination of the following:

• Maintenance and testing; or
• Emergency demand response in situations when a blackout is imminent—either the reliability coordinator has declared an Energy Emergency Alert Level 2 as defined in the North American Reliability Corporation (NERC) Reliability Standard, or there is a deviation of voltage or frequency of 5% or greater below standard voltage or frequency.

You may operate the emergency generator for 50 hr/yr of the 100 hr/yr allocation for:

• Nonemergency situations, if there is no financial arrangement;
• Local reliability as part of a financial arrangement with another entity if specific criteria met (existing RICE at area sources of HAP only); or
• Nonemergency situations as a supply power as part of a financial arrangement with another entity under certain conditions that are meant to avert the interruption of power supply in your local area or region.

Not only can generators be an environmental hazard but they are also a potential hazard for workers. Tomorrow we will take a look at how workers can keep safe when using portable generators.