Generator Downsizing for Beam Pumps: Flywheel Load Levelling on Diesel-Powered Oil Fields

Customer Requirements

In this case study, a Peak Power 200 flywheel system was deployed on a beam pump in parallel with a diesel generator. The Peak Power 200 provided significant load-levelling, allowing the generator to be downsized and resulting in substantial fuel and emission reductions.

Beam pumps (also known as pumpjacks, nodding donkeys, or sucker-rod pumps) are a form of artificial lift system used in oil production. They consist of a beam and crank driven by a large motor, which in turn drives a sucker rod that lifts oil from the well. Modern beam pumps are typically powered by electricity from the grid, or by diesel generators in remote locations where grid power is unavailable.

Beam pumps present several operational challenges for diesel generators:

• Cyclic power demand: the beam pump power cycle is highly cyclic, typically with a period of 4–10 seconds depending on the operating settings. This continually varying demand requires an oversized generator, which negatively impacts fuel consumption and maintenance requirements.
• Reverse power conditions: as the beam drops back down, reverse power conditions occur. While diesel generators can manage reverse power, doing so typically requires larger generators and can reduce the lifespan of generator components.
• Power factor issues: beam pump systems may operate with adverse power factors. Across-the-line induction motors exhibit lagging power factors, while pumps fitted with variable speed drives can produce leading power factors due to capacitor banks.
• Harsh environmental conditions: oil production sites are often located in remote areas with extreme conditions. High ambient temperatures, humidity, dust, and sand can increase wear rates on generators and electrical equipment.
• Continuous operation: beam pumps generally operate 24 hours per day. Servicing is typically performed by temporarily switching in a spare transportable system to avoid interruption to production.