Table 2 Description of data and criteria used to test for the presence of key system conditions
From: Electric transmission value and its drivers in United States power markets
Condition | Relevant measurements | Measurement granularity | Criteria |
|---|---|---|---|
Unforeseen intraday variation | (a) Magnitude of the price change between day-ahead and real-time markets ($/MWh) (b) Magnitude of the price change between day-ahead and real-time markets as a percent of the day-ahead price magnitude (%) | Nodal | \(\left(a\right)\ge \$40/{MWh}\) AND \(\left(b\right)\ge 50\%\) |
High net load | Electricity load less generation from wind and solar (MWh) | ISO/RTO | Top 5% of hours for that node within the study period |
High renewable generation | Sum of generation from wind and solar (MWh) | ||
Cold weather | Effective heating degrees (i.e., the difference between the measurement location’s neutral heating temperature and the day’s mean temperature) (°F) | ISO/RTO OR regional for ISO/RTOs with very wide geographic range | Top (coldest) 5% of days for that node within the study period AND Effective heating degrees > 0 |
Hot weather | Effective cooling degrees (i.e., the difference between the day’s mean temperature and the measurement location’s neutral heating temperature) (°F) | Top (hottest) {1%, 5%} of days for that node within the study period AND Effective cooling degrees > 0 | |
Designated events | NERC-identified periods of grid stress and key weather events identified in the literature (e.g., named storms, heatwaves). A complete list of events and their dates is available in Supplementary Table 2. | National | One or more designated events occurred that day |
