As renewable energy becomes more pervasive, utilities will need to creatively manage their loads with natural gas generation, automated demand response and grid storage, according to a report from Lux Research.
The study, “Cloudy with a Chance of Energy: Evaluating Technologies to Manage Grid Intermittency” emerged from a number of others that looked at the maximum capacity for renewable energy sources and a Lux study that considered opportunities for grid storage technologies, said Lux Research analyst Brian Warshay.
He wanted to see what the most cost-effective ways to manage renewable energy intermittency were. As utilities begin approaching the 30 percent threshold set by local government mandates, they could face intermittency challenges, Warshay said.
“Resources depending directly on the wind or sun for their fuel bring with them the same uncertainty as the evening news weatherman,” according to the report.
“It’s not enough to look at average annual power generation,” Warshay said. “You have to determine how needs are going to fluctuate throughout the day.”
Warshay said he found that automated demand response, which works with major energy users to allow the utility to shift their energy use during peak demand hours, is the most cost-effective way to manage up to 2 percent of peak load. That’s enough by itself in regions where renewable energy makes up about 10 percent of the total generation.
It works particularly well to mitigate intermittency with existing wind generation, he said.
Issues with solar power intermittency are less pervasive right now and harder to study, Warshay said. “Solar penetration is very low except in some localized areas like Southern California and Germany."
Grid storage and batteries seem to be the best answer for solar, he said. “In most regions, the cost is quite high for grid storage until you reach a high concentration of solar,” Warshay said.
But natural gas generation is the easiest answer to all intermittency issues, though not necessarily the cheapest – especially as renewable penetration grows. “Gas can throttle up or throttle down easily,” he said.
And that works well to supplement demand when the wind slows or clouds cover the sun. But as renewable generation becomes a greater percentage of generation, natural gas generation that’s only used part time will be an expense in the form of underutilized assets.