*4.1. Electricity Demand*

Average annual electricity demand estimates for LADWP's water system from 2020 to 2050 for each scenario are presented in Table 3. For all four scenarios, electricity demand slowly grows over time in almost all projected years between 2020 and 2050. Between 2020–2030, S1 and S2 show a lower electricity demand for water compared to the historical average year. In period between 2035 to 2050, S1 continues to be less energy intensive than the historical average while S2 results in a jump in electricity demand in 2035 due to the large expansion of the IPR supply. The dry weather scenarios (S3 and S4) have higher energy requirements compared to the historical average in almost all studied years, but scenario (S4) has lower electricity demand growth compared to LADWP's 2015 UWMP scenario (S3). In the short-term, electricity demand for S3 and S4 is close to the historical average year while over the long-term, much higher electricity demand is observed. Long-term electricity demand for aggressive local water supply scenarios (i.e., S2, S4) are close in magnitude, despite their differences in hydrology conditions.

More details about the electricity demand and carbon dioxide emissions are presented for the year 2035 in Table 4. The year 2035 is chosen because most water targets are set for that year in the Los Angeles City's Green New Deal plan [24]. Less energy-intensive supplies in S1, such as stormwater capture and aggressive water conservation, reduce water demand and offset energy-intensive MWD imports, such that electricity demand for water in 2035 in this scenario is lower compared to the historical average. By contrast, the S2 aggressive local water supply case in 2035 has total energy requirements that are moderately higher than the historical average (16%). In other words, there are neither significant energy penalties nor energy savings for adopting an aggressive local water supply system. Accordingly, replacing the water pumping loads associated with importing water from MWD, with the energy demands of advanced treatment and pumping, for local water recycling results in a nearly equivalent overall energy footprint. However, the distribution of who provides this electricity for the water supply in each respective scenario changes substantially, and thus has important implications for electric utilities across California. In the high local water supply scenario (S2), water-related electricity provided by LADWP increases over 6 times (from 180 in historical reference year to 1100 GWh in 2035), such that the electricity demand for water grows from approximately 0.8% of total LA's system load in the historical average year to 4% in 2035. At the same time, the electricity that would have otherwise had to be delivered to water pumping infrastructure outside of LADWP's electricity service territory is dramatically reduced as energy intensive imports from Northern California and the Colorado River decrease. Thus, although the amount of electricity consumed in the reference case versus the high local supply case (S2) is similar, the relative fraction of electricity delivered by electric utilities (i.e., LADWP versus other Investor-Owned Utilities in CAISO) shifts dramatically with large electricity demand growth implications for LADWP. While the decarbonized future electric grid significantly reduces the emissions associated with electricity consumption by definition, our analysis indicates that growing water-related electricity demand served by LADWP can increase the total amount of carbon dioxide emissions associated with LADWP's water supply, even with a cleaner future electric grid. But total water-related emissions (i.e., considering the emissions associated with LADWP, as well as other utilities in CAISO) will likely decrease by 2035 compared to historical reference in average weather scenarios because of grid decarbonization.

**Table 3.** Average total annual electricity demand for LADWP's water supply for the historical reference and projection years between 2020 and 2050 for S1-S4 scenarios. All values are in GWh and are rounded to two significant digits.


**Table 4.** Annual electrical electricity demand and CO2 emissions for the reference year and 2035 projections for all four studies scenarios. Note that percentages of water-related electricity demand, calculated in reference to total electricity demands in LADWP and CAISO regions, are calculated based on LADWP's 2017 Retail Electric Sales and Demand Forecast [42] and CAISO demand projections reported in California Energy Demand 2018–2030 Revised Forecast [43], respectively. Electricity demand and emissions values are rounded to two significant digits.


1 We applied an average annual growth rate of 0.84% to CAISO total electricity demand forecast for year 2030 in [43] to estimate total electricity demand for 2035.

The dry year scenarios, S3 and S4, have higher energy needs than the average weather year scenarios due to the limited availability of water from LAA that requires no energy for pumping (which is accommodated by a higher reliance on water supplies from energy-intensive sources). The aggressive water conservation programs implemented in S4 reduced overall water supply needs compared to S3 and hence had lower electricity demands. Considerable amounts of energy were consumed in both S3 and S4 to import water from outside LADWP (i.e., from pumping projects

served by Investor Owned Utilities in the CAISO region), but significant electricity demands also occur within LADWP due to increased supply from recycling. Therefore, for S3 and S4 in contrast with S1 and S2, we see a more distributed burden of energy among CAISO and LADWP regions. Higher water-related carbon dioxide emissions are expected for S3 and S4 than S1 but approximately similar to S2. The magnitude of total emissions in S3 and S4 can be lower than historical average if the electric grid decarbonizes significantly by 2035.

#### *4.2. Main Drivers for Electrical Energy Demand*

The relationship and relative impact of population growth, water conservation, and water supply mix on electricity demand in the year 2035 is compared to the historical average in Figure 4. This IDA analysis suggests that shifting the water supply portfolio from a more energy intensive system, on average, to a lower energy intensive system is the main driving factor for reducing energy consumption in S1 compared to the reference year. By contrast, transitioning to a water supply mix with more local water supplies in S2 leads to only a slight increase in electricity demand, which means that the average energy intensity of the water supply system in 2035 is slightly increased from the reference historical average. In S1 and S3, the impact of water conservation on reducing electricity demand for water is almost similar to the impact of population growth. In S2 and S4, however, aggressive conservation exceeds the impact of population growth on electricity demand for water. In S3 and S4, electricity demand is slightly higher than the historical average, due to combined effects of aggressive conservation and a shift to more energy-intensive water sources.

**Figure 4.** Driving factors for electricity demand changes in 2035 versus the historical average reference year for the four studied water supply scenarios for LADWP.
