The value of solar power on the electric grid continues to increase, but as the amount of solar power increases its variability can add some challenges. However, solar farms can be used as a flexible resource to provide power and grid-reliability services, while reducing costs and emissions, a new study finds.
Solar power is typically operated as a must-take resource, that is all the power provided by a solar farm at any given moment must be used as its generated. The variability in that setup causes forces electric generation sources like natural gas or hydroelectric resources to change how much they put on the grid in response to the solar fluctuation. However, a growing body of evidence shows that solar power can provide grid-reliability and dispatchable energy, increasing the value of solar and reducing costs.
“The study confirms our intuition that solar can provide the most value to the system if grid operators fully utilize the flexible dispatch capabilities of solar power plants, especially under increased solar penetration levels,” said Arne Olson, Senior Partner at E3. “Utilities and grid operators should stop thinking of solar as a problem to be managed, and start thinking of it as an asset to be maximized.”
The most recent study evaluated the impact of solar power on Tampa Electric Company (TECO), which is preparing to add 600 megawatts of solar power to its electric grid. It was conducted by Energy and Environmental Economics and sponsored by First Solar, was released today (Oct. 24).
The study looked at the four different modes that solar power can be operated in: must-take, curtailable, downward dispatch, and full flexibility. Each, in order, allows for more flexibility on the electric grid, even before adding in energy storage, and each step allows for more solar power on the grid as well.
“By leveraging the full suite of operational capabilities that all First Solar resources are already equipped to provide, solar can become an important tool to help operators meet flexibility and reliability needs of the grid,” said Mahesh Morjaria, Vice President of Systems Development at First Solar. “Such capability makes it possible for solar to go beyond a simple energy source and instead contribute to important system requirements the way conventional resources do.”
Under the fully flexible mode solar power could generate 22 percent annual cost savings for TECO as it begins to provide close to 30 percent of the utility’s generation needs. The other modes also generated savings, but they topped out in savings earlier.
The findings also reaffirm a study in California, which evaluated the California Independent System Operator (CAISO). That study was conducted by First Solar, CAISO, and the National Renewable Energy Laboratory. found that solar can be operated flexibly, and in fact can respond much faster than conventional resources to instructions from the grid operator.
The recent study concluded that as more renewable energy comes online planning must include considering the least-costly manner of operating the electric grid in the present as well as the future. “If system operators can control the power output of variable renewable resources, these resources can be viewed as assets that help to maintain reliability rather than liabilities that create operational challenges,” the study stated.Tweet