With energy experts forecasting substantial increases in solar power in the coming decades, GE researchers are working with Arizona Public Service, the state’s largest electric utility, to understand how large amounts of solar can best be integrated into today’s grid.

APS, along with four partners, including GE, recently was awarded a $3.3 million High Penetration Solar Deployment grant from the U.S. Department of Energy. The comprehensive first-of-its-kind study, which was approved earlier this month by the Arizona Corporation Commission, will take place in Flagstaff, Arizona. The team will help identify methods and technologies to optimize grid reliability and efficiency with the high concentration of distributed solar generation.

“APS’s solar demonstration project provides a great opportunity to understand the grid’s future needs as renewable energy resources like solar become a larger part of the nation’s overall energy portfolio,” said Kathleen O’Brien, project leader for GE and an electrical engineer in GE’s Smart Grid Lab. ”Much of the focus has been on new cell developments and system improvements to make solar more cost competitive, but the larger question is how to reliably integrate the higher penetrations of solar power expected. Through this study, we hope to gain more insight and answers.”

Specifically, O’Brien said that her team wants to understand:

  • What are the current and new technologies that are needed to accommodate higher penetrations of solar? And at what point will they be needed?
  • What changes can utility controllers expect in how they manage power?
  • How could the stability of the distribution network be affected by fluctuating solar power production?
  • How can the new advanced grid features of the GE Solar Inverter improve system stability and power quality?

The utility plans to integrate 1.5 megawatts of solar power on a single “feeder”, or energy distribution area. Approximately 600 kilowatts will come from residential photovoltaic (PV) rooftop installations; 400 kilowatts will be generated from installations on commercial business properties; and 500 kilowatts will be incorporated from a utility-scale solar park installation.

The project team will leverage GE’s renewable energy and utilize grid integration expertise as well as GE’s energy power electronics. GE’s Brilliance solar inverter will be used by the utility to handle power conversion from the utility-scale solar installation. This inverter was built from the same platform of power electronics, monitoring and controls that GE uses to enhance wind energy grid integration. It’s SunIQ* grid features were developed to make solar plants “smarter,” coordinating the components of a large-scale installation to behave similar to a conventional power plant. In addition to providing the solar inverter, GE researchers will be collecting data and doing power systems analysis on how the large influx of solar into this distribution network impacts the grid.

According to the U.S. Department of Energy, solar installations in the U.S. are expected to exceed 6,000 MW by 2010, more than triple what the installed base was just two years ago. What’s particularly striking is just how rapidly solar power is growing. The cumulative annual growth rate in solar is expected to be as high as 41 percent through 2012, more than double a healthy 22 percent growth rate in wind power.

In recent years, the growth in renewable energy resources such as solar already has exceeded more traditional hydrocarbon sources. According to New Energy Finance, a leading provider of industry information and analysis to investors, corporations and governments, demand for solar energy has grown about 30 percent per year over the past 15 years, while hydrocarbon energy demand typically grows less than 2% a year. This growth, and the substantial growth forecasted for solar in the future, point to an energy portfolio that is more diverse and more renewable energy intensive.

As the world seeks cleaner, more efficient ways to generate power, distributed energy systems, or localized power systems where power is generated and delivered in close proximity to its customers, have great potential for enabling a higher penetration of clean, renewable power sources into the electrical distribution network.

Because distributed energy systems are often decentralized from the larger electric grid network, renewable energy can assume a much larger part of the overall energy portfolio for a given system. That is why the solar demonstration project with APS provides such an excellent case study for simulating how larger amounts of solar power impact the grid infrastructure. Although 1.5 megawatts of solar by itself is not a lot of power, it will represent a substantial amount for the study area’s distributed energy system. GE researchers will be collecting and analyzing data over the next couple of years, with a full report to be completed by 2013.

Testing and evaluation is funded in part by the American Recovery and Reinvestment Act of 2009.