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SECTION 5: HISTORICAL ELECTRICITY USE AND RATE SCHEDULES 7 SECTION S, HISTORICAL ELECTRICITY USE AND BATE SCHEDULES The Agency purchased 18,284,786 kWh in calendar year 2016. This implies an average use of 2,087 kW throughout the year. Note that the Agency used somewhat more electricity than this, but a portion of this use was offset by the existing hydro generator. There are 31 main Southern California Edison (SCE) electric meters throughout the city serving the water system. Some of these just serve one well pump or one pressure reducing valve. Other meters serve multiple booster pumps and well pumps at a given pump station. 5.1 RATE SCHEDULES The largest electric loads are served by TOU-8-13 rate schedules. Smaller pumping loads are served by TOU-PA-3 and TOU-PA-2 rate schedules. Other meters that just serve a pressure reducing valve (instrumentation, light, ventilation) are served by the TOU-GS-1 rate schedule. These are all Time of Use rate schedules. The most expensive electricity is sold during the summer On Peak period, which occurs from noon to 6 pm on weekdays during June, July, August and September. SCE announced in 2017 its intention to change the hours which are billed as On Peak, reflecting the amount of solar energy on their grid during the middle of the day. The proposed On Peak hours are 4 pm to 9 pm on weekdays, representing the new grid peak demand when loads are high and are not offset by solar generation. The proposal is currently under negotiation with the California Public Utilities Commission. The final outcome is uncertain, but the consensus is that the new On Peak period will be as requested by SCE, or within an hour of the request. Projects in this report will be evaluated based on the SCE proposed rate schedule. Even though it is not finalized, the proposed rate schedule should give a more accurate picture of the likely savings from these projects. The new time of use periods will not have a significant impact on the hydro turbine project because the turbines will typically operate the same during the afternoons as they do during the evenings. The new time of use periods, however, will adversely impact the value of solar energy. Under the current rate schedule most of the solar energy generated offsets the more expensive electricity of the On Peak and Mid Peak periods. Under the proposed rate schedule most solar energy will offset the less expensive Off Peak electricity during the summer and Super Off Peak electricity during the winter. The solar savings are calculated by calculating the performance of the solar system for every hour of the year, based on a Typical Meteorological Year, and applying the energy and demand costs for that hour to assemble a bill for every month of the year. Newcomb I Anderson I McCormick 19H-1 5 CITY OF SANTA ANA