By Linda Fresques
NMSU researchers pioneer new power system paradigm
Nearly everyone living in New Mexico and West Texas was impacted by the periodic rolling power outages caused by the record-breaking temperatures that froze the usually temperate desert environs in early February last year. Not excluded was a group of engineers from the NMSU College of Engineering who used the unprecedented event as impetus to further their research on emerging paradigms for power system delivery and supply.
Small power systems, known as microgrids, could enable homeowners, businesses, neighborhoods or perhaps large government installations or school systems to generate their own power, preferably through renewable sources of energy such as solar or wind, that complement the existing electric utility system. Such systems could add reliability to power delivery and reduce costs.
“The existence of microgrids might have helped to reduce the severity and geographic magnitude of the situation. Instead of relying on the generation of power from a severely stressed generation system that supplies a gigantic grid, we could have relied on our own generation of power and have uninterrupted service,” said Satish Ranade, professor of electrical engineering and head of the Electrical Utility Management Program.
Ranade, along with Sukumar Brahma and Wenxin Liu, assistant professors of electrical engineering, led a multi-faceted effort to investigate the development and modeling of microgrids. Currently, NMSU faculty are actively engaged in research that focuses on public policy issues, development of microgrid designs, development of advanced control systems, and prototype implementation under grants from the DOE, National Science Foundation, Office of Naval Research, Sandia National Laboratories, the California Energy Commission, Raytheon, and the NMSU Office of the Vice President for Research.
Microgrid systems are able to integrate renewable energy resources and generate power closer to where it is used. When equipped with modern communications and control technology, microgrids provide a robust resource to complement central station generation.
Computerized communication and control of microgrid systems is one of the biggest challenges, said Ranade. “It’s easy to control power distribution over a large geographic area from a single source, but we don’t have the tools to do this over a distributed network safely. And safety is the prime concern.”
During last year’s rolling blackouts, the NMSU campus was able to continue providing power for essential services, such as fire, police and communications networks, through the use of its own co-generation plant. Experienced power professionals worked in conjunction with El Paso Electric to use campus-generated power when needed, but the implementation was done manually.
“Electric utilities in the area did a commendable job of managing rolling outages and to our knowledge there was no instance of uncontrolled loss of power supply to customers,” said Ranade.
Adding multiple sources of energy generated by different methods complicates the ability to detect issues and control the system.
Liu is conducting research focused on advanced computer control and optimization models that can improve the efficiency and reliability of microgrids during normal and abnormal operating conditions. Liu is achieving advanced design and improved performance by introducing recent developments in computational intelligence to power system research. The algorithms that he has been working on can be applied to both terrestrial and naval shipboard power systems.
Brahma is investigating aspects of protection and fault location in microgrids. Due to the unique topology and varied generation resources in a microgrid, the established methods of protection and fault location for distribution systems do not apply.
“We need methods to protect the network—the ability to sense problems with the system and automatically turn parts of it on and off in a safe manner so that critical services are not jeopardized. A resident or small community generating their own power on a nice sunny day might not be aware that there is something wrong with the system,” said Ranade. “Advanced communications and controls could detect problems and help coordinate customer generation for safety.”
While the benefits of co-generation are evident, the rules of engagement are not in place yet.
“We are not just engineering geeks developing new technologies, we are also addressing the policy and economic issues related to implementation,” Ranade said.
Assistant Dean Patricia Sullivan, also an industrial engineering Ph.D. candidate, is developing methods to analyze the associated public policy on customers making investments in microgrid systems, utility companies integrating the generation and the economic effects on the general public. This work also benefits from collaboration with the NMSU Center for Public Utilities within the College of Business.
While interest in renewable generation continues to grow, access among the broad socio-economic populace has been slowed by the economic downturn. The federal government offered stimulus money and tax incentives for homeowners and businesses to retrofit existing buildings to be more energy efficient. At the same time, the trend toward tightened lending practices made it more difficult to do so.
“Enthusiasm for home and industry-based renewable generation argues for a policy framework that is beneficial to the full spectrum of stakeholders,” Sullivan said.
A goal of the New Mexico Green Grid Initiative, a cooperative effort among the national laboratories, utilities, energy businesses and research universities including NMSU, was to set up fully integrated microgrids for testing and evaluation in one rural area and one urban zone starting in 2010. While several possible sites have been identified, financial backing is slow to come.
NMSU is, however, working toward the demonstration of an autonomous microgrid sometime within the coming year, as well as a microgrid teaching lab equipped with wireless communication and automatic controls. They will work in conjunction with several prototype houses located on the east end of campus that were outfitted with solar panels. The residences are operated by the College of Engineering’s Southwest Region Experiment Station, established in 1977 by the U.S. Department of Energy to conduct both public and private sector renewable energy testing since the late 1970s.
“NMSU really is a pioneer in power research and experimentation with renewable energy,” Ranade said. “We are uniquely positioned to contribute toward the development of reliable power sources and delivery to a varied customer base in New Mexico.”