For most utilities in California, meeting the state’s renewable portfolio standard of 33 percent is challenging enough. But not for Burbank Water and Power, which has set the bar even higher. The municipal utility could obtain 66 percent of electricity from renewable sources by 2025.
To meet the state goal and beyond, BWP is building a single integrated system that will ultimately manage forecasting, control generation, system voltage and switching to optimize available resources. Eventually, it will also be able to integrate storage and real-time demand response.
One of the key elements is an integrated automated dispatch system. The IADS from Schneider Electric has been up and running since early November. The IADS integrates demand and supply resources into the real-time and day-ahead operations at the utility, which serves about 51,000 customers, including many large movie studios and media companies.
“With thermal resources, we think in terms of peak,” said Fred Fletcher, assistant general manager of power supply at BWP. “But with solar and wind, you have to think in terms of what we will do when the wind blows and the sun shines.”
The question of managing renewables and assets at the grid edge is one that many utilities are grappling with, but few are embarking on such sophisticated systems to help answer it. Renewables, primarily wind and solar, currently make up about 25 percent of BWP’s energy supply, although at some hours, “it’s significantly higher,” said Fletcher. By 2016, he expects about 50 megawatts of solar and 30 megawatts of wind on BWP’s grid, which supplies a peak of about 120 megawatts.
“It’s not needed today,” Fletcher says of the IADS, “but we’re looking toward April 2016 when it will be a challenge.” He points to that date because at that time of year, the wind and sun are strong, but load is relatively light, so renewables could make up more than half of generation around that time.
The IADS uses sophisticated models that look at the forecast over the coming week and calculates BWP’s net thermal resource needs. The system then calculates purchase contracts based on the weather and load needs and evaluates how much of adjustable thermal resources can be tweaked or taken offline. The day-ahead and real-time models use the system to calculate down to 30-minute intervals. The system is capable of working in five-minute intervals to control thermal generators in BWP’s territory to respond to changing renewable output, but the utility is not using the system yet down to that level of granularity.
“There’s nothing simple about it,” John Dirkman, senior product manager for smart grid global at Schneider Electric, said of the IADS. He noted that the complexity of bringing weather, economic scheduling, SCADA and generator controls all into one system has been challenging, but rewarding.
The Need For Better Forecasting
Weather has always been integral to utility operations. In recent times, the hottest days of summer have pushed grids to the limit as AC use soars. Inclement weather causes outages, and seasonal weather patterns affect hydro generation.
But with renewable portfolio standards across the globe, the need for more accurate and real-time weather forecasting has become critical. Companies like IBM have released new weather tools for utilities. Schneider, which bought Telvent five years ago, also got DTN as part of the package. Telvent bought DTN about five years ago. One of its products was WeatherSentry, which is now integrated into the IADS.
Telvent and Schneider have since refined the weather tool, and Burbank even bought its own weather station as the IADS was built. Schneider also takes historical weather data and overlays that onto load profiles for Burbank to get a baseline. The system then uses a technique called particle swarm optimization to find the best solution based on baseload correlated with current weather and load predictions. “It’s a way to solve problems that may not have exact solutions,” said Dirkman.
The sophistication of the algorithms means that there are plenty of kinks to work out. Sometimes the modeling offers solutions that are off target by megawatts. At times, the system has failed to communicate effectively with the generators. The issues, however, are not fazing Schneider or BWP. “The more complex the systems are, with this level of integration,” said Dirkman, “it just always takes longer than you think it should.”
Beyond Renewable Integration
As BWP works with Schneider to train the system, it is also looking further down the road. One possible path of development is to create tools and methods to balance the grid, especially as the utility inches toward levels of renewables penetration that exceed 50 percent.
Fletcher is evaluating various storage options, such as compressed air energy storage, pumped hydro, zinc-air batteries and other technologies. He is still just working on the mathematics of how different storage systems impact the economics of wind and solar generation and the utility’s operating cost. He guessed BWP wouldn’t have a system in place for years, maybe even more than a decade.
The second issue is the changing nature of the business altogether and how best to serve and include customers. “The electric industry isn’t just about selling kilowatt-hours anymore,” said Fletcher. “That simplistic approach is going away.” BWP is in talks with Schneider Electric about what type of demand response is needed to work with high levels of renewables and what sort of systems could entice its large studio customers, which aren’t interested in shutting down productions to shed a few megawatts.
From automated demand management that can respond to grid signals to microgrids that might be supported by BWP, Fletcher said the utility was investigating many options to morph its business model to serve its customers in the future. “When we look back on these changes,” he said, “it will seem obvious.”