August 21, 2012

Virginia Tech Research Showcases Solar Energy Storage In A Power Grid

Brett Smith for - Your Universe Online

Because the generation of solar energy is reliant upon seasonal factors and available daylight, it is highly unresponsive to demand and market pressures.

To solve this problem, two Virginia Tech electrical engineers have devised a way to economically store solar energy in the power grid that can be tapped into as needed, according to their award-winning paper presented at an international engineering conference.

In the paper, Reza Arghandeh, a doctoral candidate at Virginia Tech, along with support from Robert Broadwater, a professor of electrical and computer engineering at the university, outlined a breakthrough optimization algorithm for a large scale Distributed Energy Storage (DES) system.

The system would utilize a fleet of batteries and connected distribution transformers to withhold distributed photovoltaic power before it is bid to market, according to the paper.

“Selling the household generated electricity into the electric energy market and the storage of electricity in storage systems and demand control systems provide a variety of economic opportunities for customers and utility companies to use more renewable resources," Arghandeh said.

He added that the new system would create a financial incentive for those looking to invest in solar energy technology.

"Withholding distributed photovoltaic power, probably gained from rooftop panels, represents a gaming method to realize higher revenues due to the time varying cost of electricity," Arghandeh said.

Because the cost of energy is higher at peak hours, such as the early evening hours when families return home from school and work, the Virginia Tech system would use this market pressure to maximize profits by releasing stored solar energy during this time. Incidentally, many power companies, like Con Edison and other regional providers, have systems in place that allow them to offer optional pricing packages that correlate to usage hours.

Arhhandeh said the key to his system is using the optimization algorithm to leverage market forces for maximum profits.

"The distributed photovoltaic power adoption can be controlled with the help of real-time electricity price and load profile," he confirmed.

The development of the solar energy storage system coincides with the power industry´s shift toward a so-called ℠smart grid´ that more actively responds to improve its efficiency, consistency, and sustainability.

Arhhandeh and Broadwater said solar technologies should be fully integrated with the existing technologies on the grid, like energy storage and control systems. Their approach depends upon the forecasting of load variation, market prices, and photovoltaic generation. Using this knowledge, the system creates a charging and discharging schedule with the maximized operational benefits.

The research presented by the two Virginia Tech engineers won the award for best student paper at the 20th International Conference on Nuclear Engineering (ICONE), held in conjunction with the American Society of Mechanical Engineering Power 2012 Conference at Anaheim, Calif.

ICONE focuses primarily on addressing the needs of the nuclear power industry; however the conference also addresses the technical state-of-the-art technology that can be applied to the power industry. A statement to the conference website describes it as “the conference for technical professionals that design, build, operate, overhaul and maintain power plants, or do power plant and equipment R&D.”