What’s Constant About Variable Speed Drives? Energy and Cost Savings
Some technology that helps large industrial plants reduce fuel consumption and save energy is easy to understand. Examples include combined-cycle power plants that capture the heat from gas turbines to boil water to run steam generators, or engines that can run on the methane gas produced by landfills.
Other technology, while still making a comparably significant impact, may need a little more explanation. One example are the electrical Variable Speed Drive (eVSD ) systems from GE that were recently selected for the new Yanbu 3 power and desalination plant in Saudi Arabia, to power the boiler feed pumps, which will supply water to the steam boilers at the desalination facility.
While a fixed-speed motor has only two operating conditions – either full speed or off – variable speed drive systems can adjust the speed to changes in load. For instance, if the demand of water falls to 50%, the pumps’ operating speed can be reduced accordingly leading to significantly less energy consumption. Moreover, eVSDs also reduce the wear and tear on plant equipment and systems that is caused by full speed operations and the frequent On/Off of a fixed-speed motor.
GE Power Conversion’s variable speed systems for the Yanbu desalination plant include 15 induction motors, 15 input transformers and 15 medium voltage Variable Speed Drives. These GE systems will provide the desalination facility’s operator — the Saline Water Conversion Corporation — with four benefits: greater energy savings, operational flexibility and reliability, and lower maintenance costs.
Yanbu 3 is located on the Red Sea coast about 200 kilometers north of Jeddah and will provide 2,700 megawatts of reliable electricity and 550,000 m3/day of clean water for 8 million residents and businesses in the region.