Impacts of Mica Units 5 and 6 on Synchronous Condense Operations and Aquatic Life (Addendum #2 to CLBMON-1 Mica Dam Total Gas Pressure Monitoring and Abatement Program
Author: E. Plate, E. Smith, Y. Bychkov
Assess the impact of synchronous condense operations of all Mica turbines on dissolved gas supersaturation. Assess the impacts of potential TGP increase on the aquatic environment and fish populations down stream of the Mica Dam
The six generators in Mica Dam were operated at a combination of different modes to respond to energy demands. All six turbines were either generating (G), idling (I) or were operated in SC mode (S). Operating modes which had one generator in synchronous condense mode and the other five idling, and two in synchronous condense mode and the other four idling (S1 I5 G0 and S2 I4 G0) had the highest TGP mean values at 107% and 108% respectively at 0.2 km below Mica Dam. . In these operating scenarios, flow out of the dam was generated completely by turbines in the SC mode without any additional flow from generation to dilute water with TGP values. When no generator was operated in SC mode, the median TGP values were 101%.
TGPS levels above the BCWQGs appear to be independent of the identity of the generator. TGPS for all generators are the result of continuous (>8 h) operation of two generators in parallel SC mode while the other four generators are idling. This result is based on the findings that the BCWQSs were exceeded in similar situations when Generators 3 and 4 (2017) and Generators 1 and 2 (2015) were operated in SC mode for longer periods of time (Plate et al. 2016).
A switch from SC mode to short periods (<1 h) of generation and flow through the generator appeared to stop the increase of TGP values and led to TGP reductions of 5-10% and in most cases would bring the TGP value below the BCWQ guideline of 110%. TGP monitoring results showed that exceedances of the 110% TGP BC Water Quality Guideline (BCWQG) did not occur based on normal operations (idling or generating) of any of the six generators in Mica Dam. In contrast, TGPS values reached a peak of 122% when two generators were operated in SC mode while the other four generators were idling (S2 I4 G0 mode) for 12 h. This was most evident 0.2 km downstream of MD on May 19 when, following a 12 h period of SC mode operations in two generators (S2 I4 G0) one generator was switched to generation mode for 3.75 h and TGP values fell by 12% from 112% - 100%, thus reducing TGP values below the BC Water Quality Guideline (BCWQG) value of 110% and to the baseline value of 100%. The flow through generators when generating appears to dilute high TGP levels caused by other generators that are operating in the SC mode and the lengths of generation periods interrupting the SC mode is directly controlling the amount of TGP reduction. TGPS appears to travel down the Revelstoke reservoir as a cohesive plume at a rate of 0.975 km/h when averaging observed rate of travel between the onset of SC operations and the increase of TGP levels at different distances; which were 1 h to 0.2 km, 5 h to 3.5 km, and 8 h to 11 km Therefore, TGPS in Revelstoke Reservoir has the potential to affect fish close to the dam holding in water shallower than 1 m. The TGPS peak of 122% caused by long periods of SC mode in Generators 3 and 4 on May 22 were measured at 0.2 km (Stn0) from Mica Dam. This same peak remained at 117% when measured at a distance of 3.5 km (Stn1) from Mica Dam and had a peak value of 112% at a distance of 10.5 km (Stn3) and 11 km (Stn4) from Mica Dam. Between May 29 and June 13 TGP measured 3.5 km (Station 1) below the dam was similar to values measured 0.2 km (Station 0a) below the dam. The similar values were likely based on little dissipation in the lotic section of Revelstoke Reservoir were the water surface area to volume ratio is low. Possible Mitigation Measures Changing the ratio of SC mode to generation mode to favour slightly shorter periods of SC (< 8 h at a time) and longer periods of generation (> 2 h) should keep TGP levels < 110%. Alternatively, generation (flow) through one turbine while running one or two other turbines in SC mode appears to dilute the high TGP levels to create a combined flow with TGP levels < 110%.
The six generators in Mica Dam were operated at a combination of different modes to respond to energy demands. All six turbines were either generating (G), idling (I) or were operated in SC mode (S). Operating modes which had one generator in synchronous condense mode and the other five idling, and two in synchronous condense mode and the other four idling (S1 I5 G0 and S2 I4 G0) had the highest TGP mean values at 107% and 108% respectively at 0.2 km below Mica Dam. . In these operating scenarios, flow out of the dam was generated completely by turbines in the SC mode without any additional flow from generation to dilute water with TGP values. When no generator was operated in SC mode, the median TGP values were 101%.
TGPS levels above the BCWQGs appear to be independent of the identity of the generator. TGPS for all generators are the result of continuous (>8 h) operation of two generators in parallel SC mode while the other four generators are idling. This result is based on the findings that the BCWQSs were exceeded in similar situations when Generators 3 and 4 (2017) and Generators 1 and 2 (2015) were operated in SC mode for longer periods of time (Plate et al. 2016).
A switch from SC mode to short periods (<1 h) of generation and flow through the generator appeared to stop the increase of TGP values and led to TGP reductions of 5-10% and in most cases would bring the TGP value below the BCWQ guideline of 110%. TGP monitoring results showed that exceedances of the 110% TGP BC Water Quality Guideline (BCWQG) did not occur based on normal operations (idling or generating) of any of the six generators in Mica Dam. In contrast, TGPS values reached a peak of 122% when two generators were operated in SC mode while the other four generators were idling (S2 I4 G0 mode) for 12 h. This was most evident 0.2 km downstream of MD on May 19 when, following a 12 h period of SC mode operations in two generators (S2 I4 G0) one generator was switched to generation mode for 3.75 h and TGP values fell by 12% from 112% - 100%, thus reducing TGP values below the BC Water Quality Guideline (BCWQG) value of 110% and to the baseline value of 100%. The flow through generators when generating appears to dilute high TGP levels caused by other generators that are operating in the SC mode and the lengths of generation periods interrupting the SC mode is directly controlling the amount of TGP reduction. TGPS appears to travel down the Revelstoke reservoir as a cohesive plume at a rate of 0.975 km/h when averaging observed rate of travel between the onset of SC operations and the increase of TGP levels at different distances; which were 1 h to 0.2 km, 5 h to 3.5 km, and 8 h to 11 km Therefore, TGPS in Revelstoke Reservoir has the potential to affect fish close to the dam holding in water shallower than 1 m. The TGPS peak of 122% caused by long periods of SC mode in Generators 3 and 4 on May 22 were measured at 0.2 km (Stn0) from Mica Dam. This same peak remained at 117% when measured at a distance of 3.5 km (Stn1) from Mica Dam and had a peak value of 112% at a distance of 10.5 km (Stn3) and 11 km (Stn4) from Mica Dam. Between May 29 and June 13 TGP measured 3.5 km (Station 1) below the dam was similar to values measured 0.2 km (Station 0a) below the dam. The similar values were likely based on little dissipation in the lotic section of Revelstoke Reservoir were the water surface area to volume ratio is low. Possible Mitigation Measures Changing the ratio of SC mode to generation mode to favour slightly shorter periods of SC (< 8 h at a time) and longer periods of generation (> 2 h) should keep TGP levels < 110%. Alternatively, generation (flow) through one turbine while running one or two other turbines in SC mode appears to dilute the high TGP levels to create a combined flow with TGP levels < 110%.
Resources Data:
Name: CLBMON-1-YR3-2018-04-01
Format: PDF
URL: https://www.bchydro.com/content/dam/BCHydro/customer-portal/documents/corporate/environment-sustainability/water-use-planning/southern-interior/clbmon-1-yr3-2018-04-01.pdf
Additional Info
Study Years: 2017
Published: 2018
Topics
Tags: BCWQG, Bull Trout, DGS, Dissolved Gas Supersaturation, Gas Bubble Trauma, GBT, Kokanee, Mica Dam, Monitoring Recommendations, Mountain Whitefish, Oncorhynchus Mykiss, Oncorhynchus Nerka, Operational Recommendations, Prosopium Williamsoni, Rainbow Trout, Revelstoke Reservoir, Salvelinus Confluentus, SC, Supersaturation, Synchronous Condense, Tailrace, TGP, Total Dissolved Gas PressureImpacts of Mica Units 5 and 6 on Synchronous Condense Operations and Aquatic Life (Addendum #2 to CLBMON-1 Mica Dam Total Gas Pressure Monitoring and Abatement Program
Author: E. Plate, E. Smith, Y. Bychkov
Tags: BCWQG, Bull Trout, DGS, Dissolved Gas Supersaturation, Gas Bubble Trauma, GBT, Kokanee, Mica Dam, Monitoring Recommendations, Mountain Whitefish, Oncorhynchus Mykiss, Oncorhynchus Nerka, Operational Recommendations, Prosopium Williamsoni, Rainbow Trout, Revelstoke Reservoir, Salvelinus Confluentus, SC, Supersaturation, Synchronous Condense, Tailrace, TGP, Total Dissolved Gas Pressure
Assess the impact of synchronous condense operations of all Mica turbines on dissolved gas supersaturation.
Assess the impacts of potential TGP increase on the aquatic environment and fish populations down stream of the Mica Dam
Summary
The six generators in Mica Dam were operated at a combination of different modes to respond to energy demands. All six turbines were either generating (G), idling (I) or were operated in SC mode (S). Operating modes which had one generator in synchronous condense mode and the other five idling, and two in synchronous condense mode and the other four idling (S1 I5 G0 and S2 I4 G0) had the highest TGP mean values at 107% and 108% respectively at 0.2 km below Mica Dam. . In these operating scenarios, flow out of the dam was generated completely by turbines in the SC mode without any additional flow from generation to dilute water with TGP values. When no generator was operated in SC mode, the median TGP values were 101%.
TGPS levels above the BCWQGs appear to be independent of the identity of the generator. TGPS for all generators are the result of continuous (>8 h) operation of two generators in parallel SC mode while the other four generators are idling. This result is based on the findings that the BCWQSs were exceeded in similar situations when Generators 3 and 4 (2017) and Generators 1 and 2 (2015) were operated in SC mode for longer periods of time (Plate et al. 2016).
A switch from SC mode to short periods (<1 h) of generation and flow through the generator appeared to stop the increase of TGP values and led to TGP reductions of 5-10% and in most cases would bring the TGP value below the BCWQ guideline of 110%. TGP monitoring results showed that exceedances of the 110% TGP BC Water Quality Guideline (BCWQG) did not occur based on normal operations (idling or generating) of any of the six generators in Mica Dam. In contrast, TGPS values reached a peak of 122% when two generators were operated in SC mode while the other four generators were idling (S2 I4 G0 mode) for 12 h. This was most evident 0.2 km downstream of MD on May 19 when, following a 12 h period of SC mode operations in two generators (S2 I4 G0) one generator was switched to generation mode for 3.75 h and TGP values fell by 12% from 112% - 100%, thus reducing TGP values below the BC Water Quality Guideline (BCWQG) value of 110% and to the baseline value of 100%. The flow through generators when generating appears to dilute high TGP levels caused by other generators that are operating in the SC mode and the lengths of generation periods interrupting the SC mode is directly controlling the amount of TGP reduction. TGPS appears to travel down the Revelstoke reservoir as a cohesive plume at a rate of 0.975 km/h when averaging observed rate of travel between the onset of SC operations and the increase of TGP levels at different distances; which were 1 h to 0.2 km, 5 h to 3.5 km, and 8 h to 11 km Therefore, TGPS in Revelstoke Reservoir has the potential to affect fish close to the dam holding in water shallower than 1 m. The TGPS peak of 122% caused by long periods of SC mode in Generators 3 and 4 on May 22 were measured at 0.2 km (Stn0) from Mica Dam. This same peak remained at 117% when measured at a distance of 3.5 km (Stn1) from Mica Dam and had a peak value of 112% at a distance of 10.5 km (Stn3) and 11 km (Stn4) from Mica Dam. Between May 29 and June 13 TGP measured 3.5 km (Station 1) below the dam was similar to values measured 0.2 km (Station 0a) below the dam. The similar values were likely based on little dissipation in the lotic section of Revelstoke Reservoir were the water surface area to volume ratio is low. Possible Mitigation Measures Changing the ratio of SC mode to generation mode to favour slightly shorter periods of SC (< 8 h at a time) and longer periods of generation (> 2 h) should keep TGP levels < 110%. Alternatively, generation (flow) through one turbine while running one or two other turbines in SC mode appears to dilute the high TGP levels to create a combined flow with TGP levels < 110%.