“Premium efficiency” motors use 20 to 30 percent less energy than conventional products.

It’s not easy to rate environmental problems on a scale of importance, but there’s no question that any list of serious challenges would include energy efficiency, climate change mitigation, access to clean water and effective wastewater management. Let’s take a look at a Swedish sewage pump that makes a contribution to solutions in all these areas.

Energy-efficient electric motors

About 30 million electric motors are sold each year for industrial purposes, driving fans, pumping water, generating compressed air, moving materials and much more. An installed base of some 300 million electric motors is already in place. An estimated 40 percent of global electricity consumption goes to power all these electric motors, with energy representing more than 95 percent of life cycle costs.

Electric motor technology has improved dramatically in recent decades, and energy-efficient products are now available for most applications. The highest rating, the International Electrotechnical Commission’s “premium efficiency” IE3 standard, is defined as consuming 20 to 30 percent less energy than a conventional motor, offering significant reductions in cost and greenhouse gas emissions.

Water treatment and sewage disposal

New environmental regulations for water purification and sewage treatment are important drivers for infrastructure investment even in countries that already adequate existing water and sanitation systems, particularly in Europe and North America, where treatment plants and pumping stations require continuous upgrades. In the United States, environmental authorities are increasingly requiring higher-capacity sewer networks to keep storm flows separate from wastewater.

At the global level, water management issues are taking center stage with new requirements for water and sewer infrastructure, both to meet existing needs and the threat of extreme weather events. Growing urban populations in many countries will require significant investment in drinking water purification, wastewater treatment and related systems. In emerging market countries such as China, investment requirements for construction of new sewage infrastructure are enormous. Common to all markets is that the demand for energy-efficient of pumps and other equipment will grow rapidly for decades.

Sewage pump requirements

Urbanization requires significant investment in drinking water purification, wastewater treatment and related systems.

A crucial application for electric motors is to power sewage pumps, which may be used for any liquids – often laden with abrasive particles and requiring regular starts and stops. This exposes the bearings and motors in the equipment to high stress, excessive wear and poor cooling, which adds up to stringent demands on motor output, hydraulic efficiency, lifespan, and operation and maintenance costs. Estimates of the energy consumption of a pump are always based on overall efficiency; that is, the combined efficiency of the hydraulic system and the engine. For the best possible results, these efficiencies must both be optimized.

The Swedish company Cardo markets solutions for transport and treatment of sewage under the ABS brand, where the ABS Effex series includes the company’s most energy-efficient products. The ABS XFP pump is the world’s first submersible pump with high-efficiency engines rated to the IE3 standard, as well as improved hydraulics and reliability. A number of these efficient pumps are already in trial operation at pumping facilities in Europe, where they are exceeding requirements for both reliability and energy consumption, a combination that was earlier difficult to achieve. In addition to the EU’s energy reduction requirements, other pending legislation was considered during development.

“The need to cut energy consumption is high on the agenda for many activities, and water is no exception” says Peter Aru, Cardo’s President and CEO. “We are first in the world to introduce a series of submersible pumps with high-efficiency motors that take into account the increased environmental focus and future regulatory requirements. I am excited about the development of our ABS Effex products.”

Permanent-magnet motors

Under the ABS Effex brand, Cardo has also launched ABS XRW, the world’s first submersible mixer driven by a permanent-magnet motor that reverses the usual process to produce electrical energy from mechanical energy. Permanent-magnet motors have been on the market for about 20 years, but only in recent years have lower prices for components and better technology made them attractive for most applications. Permanent-magnet motors offer several advantages over conventional induction motors driven by inverters, and despite higher initial investment costs, their high efficiency and low energy consumption give a rapid return on investment.

Within the next few years many countries will require the use of premium efficiency motors in pumps and other equipment through legislation aimed at reducing energy consumption, costs and greenhouse gas emissions.

Article published in March 2011