Diesel vs Electric: Which is better for pump systems?

  Diesel is often the preferred energy for pump systems, particularly temporary sites. But electrical pumps can be a superior alternative.

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Few people question the wisdom of using diesel-powered pumps, particularly for temporary sites or rental arrangements. Their faith is well-placed: diesel-powered portable pumps have been the standard for decades, supported by diesel’s high and reliable power output and low energy costs.

Yet, while diesel remains a strong option, electric pumps have become a viable alternative, even for temporary and rental use cases. In terms of overall cost and value, electrical pumps are a compelling alternative, and where projects consider environmental and carbon-reduction factors, it’s a leading choice, says Chetan Mistry, Strategy and Marketing Manager at Xylem Africa:

“Diesel pumps used to be the obvious choice for most conditions, but the picture has shifted enough that electric pumps are now viable alternatives to a wider range of scenarios. It’s not replacing diesel systems but provides sites with more choices. In some cases, electric pumps make more sense than diesel.”

 The benefits of electricity

The most common evaluation factor is overall pump costs. Diesel pump systems can have lower upfront capital costs than electric alternatives. However, those pump systems require frequent maintenance and refuelling. Electric pump systems have a much lower maintenance threshold and no refuelling, often offsetting their capital investment costs.

“The low maintenance and manual intervention requirements of electric systems make them less expensive over longer periods. Xylem’s research indicates that when you run pumps for longer than three months, the economics start to favour electric pumps. But even in shorter timelines, electric pumps are starting to match diesel systems due to rising fuel prices.”

Energy costs are a significant motivator for using electric systems. Over the past ten years, diesel prices in South Africa have risen by over ten rands per litre. Local electricity prices have also risen sharply from 65.51c/kWh in 2013 to around R2/kWh in 2024. However, electric motors offset much of that additional cost through higher efficiency levels, especially when using variable-speed motors that adjust to flow conditions. The question of energy cost is mitigated almost entirely when using solar-powered pumps.

Electric pumps’ lower maintenance and service requirements also offset many of diesel’s hidden costs, and the added advantages of lower carbon generation and quieter pumping conditions add to the case for using electric pumps.

Yet, they are not suited for all conditions. Notably, you need electricity to run such pumps, which can mean more outlay at the start to establish an electrical feed on a site if one isn’t available. Solar systems address this problem, but they also have upfront infrastructure needs. Still, under most conditions—and especially for rental or sites that aim to evolve from temporary to permanent pumping systems—there is a strong case to consider electric pumps.

Making the best choice

Diesel pumps are not on their way out. Diesel systems have earned a reputation for resilience in harsh conditions, and diesel pumps are better suited for some conditions, such as pumping fluids with many heavy and large solids. They are also the preferred choice for remote and rural sites where access to electricity supply is unavailable or expensive. In very short-term scenarios, diesel’s performance can give it the edge over electric systems. Diesel’s portability also facilitates easy deployment, whereas electric systems are more likely to suit permanent installations.

Diesel’s drawbacks are also not new. Noise and emissions (especially in enclosed spaces) have been issues for decades yet have not diminished the popularity of diesel pumps. Electric pump systems are not replacements for diesel but provide alternatives where diesel’s drawbacks create problems for a site.

“The best choice between diesel and electric pumps will depend on your scenario,” says Mistry. “What has changed is that diesel is no longer the only serious contender, even for temporary sites and rental plans. And as fuel prices rise while renewable energy brings down the cost of electricity, there is good reason to consider electric pumps instead of diesel pumps, rather than just assume diesel is by default the best choice.”

Don’t just bet on diesel when deciding to rent or purchase pumps for your next project. Consider your options and select the best choice for overall value. For more guidance, read Xylem’s white paper, Electric or Diesel Selection Criteria, which includes how to calculate diesel vs electric consumption rates.