ABB has a wide range of energy-efficient products, including advanced process control systems, automation products and elec-trical equipment, but perhaps the most dramatic savings of all come from our variable-speed drives, which raise the efficiency of electric motors.
Electric motors are everywhere, and the machines they run account for more than a quarter of the world's electricity consumption. Installing variable-speed drives can reduce their power consumption dramatically, typically by around 30 percent, leading to significant cost savings and reductions in greenhouse gas emissions. In applications in homes, businesses and factories, ABB drives are helping our customers to do more using less.
In Sweden, for example, the operators of a power and district heating plant run by Malarenergi AB decided to install variable-speed drives to control the performance of the many electric motors in the plant following an energy audit carried out by ABB.
ABB installed a total of eight medium-voltage drives, some of which replaced the existing resistor-based motor control systems. The improvements eliminated significant heat losses caused by the resistors and enabled the plant to produce an additional 35 GWh of electricity per year, an increase of about 5 percent.
The vast majority of electric motors in such plants control pump and fan operations, operating at full speed, even when they don't need to. Most are controlled by throttling - which is like braking a car while the accelerator is still flat on the floor. It damages equipment and wastes huge amounts of energy. Resistors and split-ring motors can also be used to control process speeds, but this approach also wastes energy.
Variable-speed drives offer an alternative, energy-efficient means of motor control. Drives allow motors to draw only the power they need to perform their tasks, cutting waste and reducing wear and tear on equipment. They also save on raw materials by improving the quality of processes they control.
Besides reducing power consumption, the new installations also lowered Malarenergi's carbon dioxide emissions and improved the reliability of its district-heating network. The best news for the plant's operators was that the payback period of the investment was just 12 months.
In 2009, The installed base of ABB drives saved an estimated 220 terawatt-hours of electric power, enough to meet the annual needs of 54 million European households and reduce global carbon dioxide emissions by some 180 million tons a year. That's like taking more than 45 million European cars off the road for a year.
As society faces the challenge of reducing environmental impact while meeting rising demand for electricity, ABB's drives will be making a positive contribution for many years to come.