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Assessing the Potential for Building Sector Retrofits to Mitigate ERCOT Electricity Shortfalls During Winter Storm Uri

Matthew J. Skiles, Joshua D. Rhodes, Michael E. Webber

Abstract

This analysis investigates energy performance of the residential and commercial building sectors in the Electric Reliability Council of Texas (ERCOT) during Winter Storm Uri. ERCOT electricity demand was modeled for the ERCOT baseline building stock as well as for the baseline building stock retrofitted with an efficiency upgrade package, an electrification upgrade package, and an efficiency + electrification upgrade package. The electrification scenario that retrofitted buildings with air-source heat pumps (ASHPs) would have lowered ERCOT daily peak electricity demand relative to the baseline scenario for every day of the year, except during the week of Winter Storm Uri. As the mean outdoor temperature dropped below -5°C (23°F), diminishing ASHP efficiency would have resulted in electrification scenario demand exceeding the two distinct baseline scenario daily demand peaks on February 15th and 16th (87.3 GW and 88.7 GW) to hit 111.8 GW and 117.5 GW. The efficiency package would have lowered daily peak demand on these days to 67.0 GW and 68.0 GW. The efficiency + electrification package would have lowered peak demand on these days to 81.5 GW and 85.6 GW. When electricity shortfall profiles were produced by comparing modeled electricity demand to actual ERCOT electricity generation during the storm, the results indicate that the electrification scenario electricity shortfall (1741 GWh) would have been larger than for the baseline scenario (1225 GWh) and the electricity shortfalls for the efficiency scenario (347 GWh) and efficiency + electrification scenario (704 GWh) would have been lower than the baseline. The efficiency, electrification, and efficiency + electrification scenarios would all have lowered summer daily peak demand due to improvements in building cooling efficiency and would have lowered annual electricity consumption by 5.9%, 6.8%, and 11.9%, respectively.

Assessing the Potential for Building Sector Retrofits to Mitigate ERCOT Electricity Shortfalls During Winter Storm Uri

Abstract

This analysis investigates energy performance of the residential and commercial building sectors in the Electric Reliability Council of Texas (ERCOT) during Winter Storm Uri. ERCOT electricity demand was modeled for the ERCOT baseline building stock as well as for the baseline building stock retrofitted with an efficiency upgrade package, an electrification upgrade package, and an efficiency + electrification upgrade package. The electrification scenario that retrofitted buildings with air-source heat pumps (ASHPs) would have lowered ERCOT daily peak electricity demand relative to the baseline scenario for every day of the year, except during the week of Winter Storm Uri. As the mean outdoor temperature dropped below -5°C (23°F), diminishing ASHP efficiency would have resulted in electrification scenario demand exceeding the two distinct baseline scenario daily demand peaks on February 15th and 16th (87.3 GW and 88.7 GW) to hit 111.8 GW and 117.5 GW. The efficiency package would have lowered daily peak demand on these days to 67.0 GW and 68.0 GW. The efficiency + electrification package would have lowered peak demand on these days to 81.5 GW and 85.6 GW. When electricity shortfall profiles were produced by comparing modeled electricity demand to actual ERCOT electricity generation during the storm, the results indicate that the electrification scenario electricity shortfall (1741 GWh) would have been larger than for the baseline scenario (1225 GWh) and the electricity shortfalls for the efficiency scenario (347 GWh) and efficiency + electrification scenario (704 GWh) would have been lower than the baseline. The efficiency, electrification, and efficiency + electrification scenarios would all have lowered summer daily peak demand due to improvements in building cooling efficiency and would have lowered annual electricity consumption by 5.9%, 6.8%, and 11.9%, respectively.
Paper Structure (9 sections, 1 equation, 13 figures, 5 tables)

This paper contains 9 sections, 1 equation, 13 figures, 5 tables.

Table of Contents

  1. Introduction
  2. Methods
  3. ERCOT population-weighted weather metrics
  4. ResStock
  5. Comstock
  6. Adjusting for modeling bias
  7. Results and Discussion
  8. Conclusions
  9. CRediT authorship contribution statement

Figures (13)

  • Figure 1: a, An isolated spike in served residential and commercial electric load during Winter Storm Uri resulted in system-wide daily coincident peak served load that was comparable to daily coincident peak served load during the summer. b, Served residential and commercial sector electric load comprised 50% – 74% of daily coincident peak served load outside of February, but increased to 83% of daily coincident peak served load during Winter Storm Uri. ERCOT2021c.
  • Figure 2: Compared to other U.S. states, a relatively low percentage of Texas residential buildings have combined ceiling and roof insulation that meets or exceeds R-38 wilson2021, the minimum level of ceiling insulation recommended for Texas climate zones by the International Residential Code IRC2021.
  • Figure 3: a and b, Most buildings in ERCOT are heated by electric resistance heating systems or heat pumps wilson2021. c, The coefficient of performance (COP) for water-source heat pumps (WSHP), ground-source heat pumps (GSHP), and air-source heat pumps (ASHP) decreases with increasing temperature difference between the heat source and the heat sink. Figure from ruhnau2019.
  • Figure 4: Methodology flowchart for modeling residential sector energy demand with ResStock.
  • Figure 5: Map of the eight ERCOT weather zones ERCOTWeatherZone.
  • ...and 8 more figures