Solar and wind power are both significant sources of renewable energy, but they are less predictable than the power available from the grid. They produce energy only when the sun shines and the wind blows.
For example, a solar energy system in California's Central Valley will produce a lot of power on a hot, cloudless summer day, and you can count on that throughout most of the season. But during the winter, while that system will still produce substantial amounts of energy, the weather conditions are more varied and it's harder to predict how much electricity will be produced on a day-to-day basis.
As communities strive to produce more of their power renewably, they will need to understand these odds and have a plan for bringing available resources online in order to operate efficiently and cost-effectively.
At the University of California, Merced, professors in the School of Engineering along with the campus' facilities management division are creating a portfolio of renewable energy options that will help UC Merced continue toward its goal of being one of the greenest campuses in the United States.
UC Merced has received a three-year $1 million Renewable Energy Secure Communities (RESCO) program grant through the California Energy Commission's Public Interest Energy Research (PIER) program.
Approximately 51 applications were submitted by businesses, universities, utility companies and other institutions throughout California. UC Merced's proposal, "Piloting an Integrated Renewable Energy Portfolio for the UC Merced Community," was one of 13 to receive funding.
"The RESCO grant will help the campus integrate three of the most promising renewable energy technologies that will help us meet our "Triple Zero" commitment," said John Elliott, UC Merced's assistant director of energy and sustainability and project manager for the UC Merced RESCO project.
"The first is energy efficiency. For the time being, it is much cheaper to save energy than to generate energy. Second is solar. The Central Valley has enough sun that it could just as easily be called 'Solar Valley.' The third is waste to energy conversion using plasma technology. This is a promising and flexible approach that will be used to efficiently generate steam on demand to supply the campus needs."
UC Merced's Triple Zero commitment is to produce as much energy as is used from renewable sources, eliminate landfill waste and produce zero net greenhouse gas emissions, all by 2020.
School of Engineering professors Carlos Coimbra and Gerardo Diaz, along with the undergraduate and graduate students working in their engineering laboratories, will develop research and collaborate with Elliot by focusing in the areas of solar forecasting and plasma gasification.
"This is a unique collaboration between engineering professors and facilities staff," Diaz said. "UC Merced is literally a 'living laboratory' due to the number of state-of-the-art technologies being tested that are actually used to provide services during the normal operation of the campus."
For the efficiency component of the RESCO project, investigators will develop a monitoring system that will allow the campus to define and maintain efficiency as a renewable resource. "UC Merced has already built very energy-efficient buildings on campus, and we will be state-of-the-art in actually monitoring and maintaining that energy performance."
Some of the work done will result in improvements and energy savings in UC Merced's Science & Engineering Building, which includes highly sophisticated research laboratories. Its electricity usage accounts for 40 percent of the campus bill and it consumes the most energy of all campus buildings.
Professor Coimbra's role in the project is to advance UC Merced's capability to rely on solar energy as a primary component of its energy portfolio. His Solar Forecasting Laboratory will further develop a precise method of solar forecasting.
By using data collected from two solar observatories at UC Merced and UC Davis, and integrating these data with information from a new 8.5-acre, 1-megawatt solar field currently under construction at UC Merced, Coimbra's work will help identify optimal sites for placement of solar energy systems throughout California. Moreover, the UC Merced solar forecasting model will be able to evaluate with unprecedented accuracy the solar resource available for power generation.
"One of my doctoral students, Ricardo Marquez, who was born and raised in the Central Valley, is refining a sophisticated forecasting model that is already powerful enough to predict accurately the solar resource available in the next five minutes, the next hour, or the next day, and this information is critical to the expansion of solar power utilization in California," Coimbra said.
Professor Diaz's lab will examine methods of converting waste to energy through plasma technology. He will work with Foret Plasma Labs to examine how to use waste, also called reject, from the reverse osmosis water filtering process and turn it into steam to supply the campus demand.
This system is unique among renewable resources, as it can be turned on and off with the flip of a switch. He is also working with the Associate Director of Campus Services Bob Avalle, to evaluate the practical aspects of using the campus waste stream as an energy source.
UC Merced's selection to receive RESCO funding - in additional to other sustainability programs and projects underway - will help the campus pilot its own sustainable energy strategy. The project, in support of energy commission's goal of advancing public interest energy research, will also serve as a model for other organizations and communities.