Utilities and generation planners have traditionally relied on hourly grid modeling to optimize their decision-making. However, as intermittent renewable energy resources are increasingly deployed, some researchers say a more granular lens is required to accurately capture the real-time dynamics of the grid.
Further, the growing relationship between weather and the supply and demand for electricity has emphasized the need for more flexible, dispatchable sources like batteries or reciprocating internal combustion engine (RICE) units. Reciprocating engines, profiled in this article, can start-up and provide energy at full load in less than 5 minutes and they have no minimum up-time or downtime.
Wärtsilä and Burns & McDonnell recently teamed up to research the value of using five-minute grid outlook modeling instead of hourly modeling. They found in a renewables-heavy grid, the value of five-minute modeling – and reciprocating engines – grows.
To further understand this research, Power Engineering spoke with Jon Rodriguez, Energy Business Director for Engine Power Plants at Wärtsilä; and Tim Carey, RICE Business Manager for Burns & McDonnell. For more, watch our interview above.
Conducting the research
Rodriguez said the teams conducted the research in multiple ways, the first by taking a backcasting approach.
“We basically looked at five years of actual data in several different ISOs, and we ran hypothetical scenarios showing the performance of a reciprocating engine plant if it were in this node with the prices that did occur,” he said.
Researchers then compared the performance of the RICE units with that of aeroderivative turbines and heavy-duty simple cycle turbines.
Rodriguez said through that analysis, the RICE units proved more valuable, to the tune of millions of dollars over that five-year period. He noted that since flexible assets like reciprocating engines act on sub-hourly timeframes, the value they provide to the grid is not adequately captured in the traditional daily or hourly models utilities use.
Researchers were also able to plug in the same operational data into a subscription forecasting service by Ascend Analytics, with similar results.
What are the implications?
Essentially, Rodriguez and Carey say utilities could be missing out on millions of dollars in value by using the traditional hourly grid modeling techniques, with increasingly sub-optimal results and rising costs for ratepayers.
According to a recently released Wärtsilä white paper produced with Reuters Events, regulators are generally unaware of this problem and utilities have “little incentive to move to more granular modeling, since sub-hourly models can only be resolved using costly computational resources.”
“Hourly data is readily available,” said Carey. “A lot of grid modelers use past hourly data, and that’s just been tradition. What we’ve found is when you do that, you’re missing out on potential value there.”
“What [we’re] trying to encourage is to take that into account when you’re trying to get your project a pencil out,” he added.
In the white paper, Uncovering the Hidden Value of Reciprocating Engines, Wärtsilä researchers say there is “an urgent need for regulators to be made aware of the shortcomings of traditional hourly and weather-normalized modeling.”
You can download and read the full white paper here.
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