Technical Brief | Continuous, Prime, and Standby Power

Baseline Technical Briefs

The Difference Between Continuous, Prime, and Standby Power

Beyond fuel considerations, generators are typically categorized in one of three ways:

Either as Continuous, those that provide Prime power, or those that operate in Standby mode. Sometimes generators are intended to act a primary source of power for an entire facility, while at other times generators are switched on only in emergency scenarios where the primary power source has failed. In order to determine which type of generator is most suitable for your application, it is critical to understand the differences between Continuous, Prime and Standby power.

Prime Power

Prime power generators serve as the primary source of power and are most suitable when power from the public utility is either unavailable, or due to cost or reliability issues, the consumer chooses not to buy from them. Prime power generators can be set up for short-term use but are designed to excel in long-term operation and are suitable for delivering reliable power in remote areas. Baseline’s Prime power generators operate on a variety of natural gas fuels including wellhead gas, making them a great fit for oil and gas operations in remote areas or those seeking to lower their electricity costs with a tailor-made, off-grid power solution.

Baseline’s Prime power generators are rated for operation at one hundred percent of their nameplate value under perfect conditions and with perfect quality fuel. Because perfect conditions rarely exist and wellhead gas of varying quality is often the primary fuel source, the typical electrical output is more realistically around eighty to ninety percent of the nameplate value. So, for a 350 kW generator, you can expect to get approximately 300 kW on wellhead gas.

Low loading (below 50%) can result in improper fuel burning and accumulation of unburnt fuel in exhaust systems, decreasing efficiency, and requiring more frequent maintenance. Low loading should be avoided even under variable load conditions. However, the flexible nature of Prime power generators enables them to bear a considerable amount of low loading as well as overloading for a limited span of time (around 1 hour in a 12-hour period). The overloading limit is usually 10% higher than the rated output power. This is especially useful when paralleling generators to meet the total power requirement as maintenance or swap-outs can be performed without impacting the customer.

Continuous Power

Continuous power is very similar to, and often confused with, Prime power. Continuous power generators are also designed to be the primary source of power for any facility and run for long periods of time, but unlike Prime generators they do not offer variable power, nor do they have the capacity to bear overloading even for a limited time period. Continuous power generators are suitable for locations that lack utility power and the load is constant. Confusion between Continuous and Prime stems mostly from terminology, where one would expect continuous to meet their needs, quite often the load still has quite a bit of variance and temporary high power demands, as is typically the case when industrial pumps reactivate after having sat idle.

Standby Power

Standby generators start up on-demand to supply backup power when the primary power source fails. Their operation times vary, depending on the make and model of the generator. Generally, standby generators should not be run for more than a few hours as there is risk of overloading when operating for an extended period. Standby generators are essential for applications where uninterrupted power is crucial and power outage can cause significant damage. Due to their essential role in healthcare facilities, standby generators are strictly regulated and maintained to ensure that emergency power systems will function properly when required. Although not as strictly regulated, standby generators also play a crucial role ensuring business continuity in many industries. Data centers, manufacturing facilities, and companies of all sizes increasingly choose to invest in standby generators as the disruption from even one minor utility power outage a year can easily justify the cost.

Closing Thoughts

To maximize cost efficiencies and ensure reliability, it is critical to properly assess your power needs and develop a solid plan. Whether you a Prime or Standby power solution, Baseline specializes in assessing every customer’s specific situation and recommending the most reliable and economical power solution.