these were different from the existing reserve products including regulation and spin/nonspin reserve, based on a number of factors (see Table 1). Other areas have determined that they have been achieving sufficient ramping without the need of a new product. In 2016, the CAISO flexible ramping product and the MISO ramp capability product were both implemented and have been procuring ramp capability and providing price signals since then. Figure 4(a) shows how these products are designed to secure resource flexibility to meet ramping needs in future market intervals due to variability and uncertainty of net load during different scheduling processes [Figure 4(b)]. Ramp requirements are established based on reliability needs in a cost-effective manner by looking both forward at load Proposed Current Regulation Up Fast-Responding Regulation Up Regulation Down Fast-Responding Regulation Down Responsive Regulation Up Fast-Responding Regulation Up Mostly Unchanged Regulation Down Fast-Responding Regulation Down Fast Frequency Response 1 59.8 Hz, Limited Duration Fast Frequency Response 2 59.7 Hz, Longer Duration Primary Frequency Response Nonspin Contingency Reserves 1 SCED Dispatched Contingency Reserves 2 Manually Dispatched Supplemental Reserves 1 SCED Dispatched Supplemental Reserves 2 Manually Dispatched Ongoing Development Synchronous Inertial Response Source: ERCOT figure 3. Current and proposed ancillary services in ERCOT. SCED: security constrained economic dispatch. table 1. A comparison of ramp products with existing ancillary services. 76 Regulation Spin and Nonspin Ramp Product What guides response Automatic Operator directed, sometimes automatic Dispatch Frequency of use Every interval Rarely Often but not every interval What it is used for Short-term changes in load and VER Contingencies Forecast errors and (several minutes time frame) ramp events Penalty price US$80-US$600/MWh (medium) Typically ≥ US$500/MWh (high) US$5-US$250/MWh (low) Nonzero bids allowed Yes: wear and tear and efficiency costs Sometimes No When deployed After dispatch interval (in between dispatch) After dispatch interval (sometimes through new contingency dispatch) Part of dispatch interval ieee power & energy magazine november/december 2017