Microgrids are Growing
Washington state received $7 million from the state’s Clean Energy Fund, which has been earmarked to improve the efficiency, security, and reliability of Washington’s electrical grid. A portion of the grant is being applied to build a microgrid in Arlington, Washington.
A microgrid is a self-sufficient local energy grid that connects to the larger electrical grid, but can break off and operate autonomously. It can generate power using distributed generators, batteries, and renewable energy resources such as solar or wind. Depending on how it’s designed, a microgrid may be able to run indefinitely.
Today, some 160 microgrids operate across the U.S. with the capacity to deliver about 1,650 MW. Multiply that by 2,600 to reach 4.3 GW — that’s the capacity forecasted by 2020. Commercial and industrial microgrids are expected to grow faster than other market segments. Much of that growth is expected to come from data centers, stores, resorts, manufacturers, and other business operations.
In the meantime, Washington’s Snohomish County Public Utility District, locally known as SnoPUD, is also building a “clean tech center” in Arlington to demonstrate the many improvements a microgrid brings to residential and business customers. For instance, rather than a community relying on the regional grid, a microgrid can run independently when bad weather or other events compromise the usual suppliers. In some cases, a microgrid can even supply power to the larger grid.
Avista, a power company in Spokane servicing 1.6 million customers and managing more than 19,000 miles of distribution lines, is using its portion of the Clean Energy Fund grant to implement a shared energy approach. Using solar panels and storage batteries to augment traditional resources and sophisticated energy management systems, Avista customers will have options to share and load balance in new ways that bring the cost of electricity down.
Chemical Processors Use Advanced Motor Drive Technology
While every manufacturing and processing plant uses electricity, those in the chemical processing business tend toward the higher end of the demand curve. Omnipresent motors and their power trains pump, mix, and convey chemicals throughout each process. They use electrical energy to do the desired work, but also waste a significant amount through heat, vibration and other losses. Management looks to reduce those losses, to keep motors running as efficiently as possible, and to extend the mean time between failure. Now, advanced motors and motor drives are making that possible.
Chemical Engineering magazine (June, 2017) quotes George Weirhauch of Baldor, a member of the ABB Group, who points out that chemical processors “…look at how to make designs more reliable and efficient. We study modes of failure that affect motor life, such as operating temperatures, vibration and things that affect motors like power supply and inverter operation, and look for new materials, design improvements and features that can reduce the modes of failure so the motor will last longer and run more efficiently.”
Motor failure can shut down an entire processing line, and due to the nature of chemical processing, restarting can sometimes take days. Reliability is therefore a paramount concern. The article outlines creative steps motor manufacturers take to assure good performance in the often-harsh chemical processing environment.
Motor drives along with high frequency sine wave filters and liquid-cooled line reactors also contribute to reliability and savings. They control the speed and torque of AC motors by supplying a variable voltage and variable frequency current. For applications that need rigorous speed control, many variable frequency drives are equipped to take feedback signals from an encoder mounted on the motor itself. That feedback loop results in highly accurate control.