Some exciting news from sunny California… The power of the sun has now been harnessed.
Renewable electricity met just shy of 100% of California’s demand for the first time on Saturday, officials said, much of it from large amounts of solar power produced along Interstate 10, an hour east of the Coachella Valley.
While partygoers celebrated in the blazing sunshine at the Stagecoach music festival, “at 2:50 (p.m.), we reached 99.87 % of load served by all renewables, which broke the previous record,” said Anna Gonzales, spokeswoman for California Independent System Operator, a nonprofit that oversees the state’s bulk electric power system and transmission lines. Solar power provided two-thirds of the amount needed.
It is an achievement. However, Canary Media points out that there’s a bit more to the story…
Understanding the full picture requires first unpacking how CAISO calculated the 97% figure. California’s in-state renewable energy production was calculated as a percentage of energy demand after accounting for transmission losses. This demand figure omits demand met by rooftop solar, which generates power for more than 1 million California customers. Because large hydropower does not qualify for the state’s renewable portfolio standard, it is also not included in this figure.
Another important caveat: The figure does not account for all demand in California, even leaving aside demand met by rooftop solar. CAISO’s system does not include the areas served by the Los Angeles Department of Water and Power and the Sacramento Municipal Utility District, two publicly owned utilities that together make up roughly 10 percent of electricity sales in the state.
April 3 was a big wind and solar day for California, coupled with relatively low demand due to mild spring weather. Across the whole day, wind contributed 24% toward meeting demand and solar contributed 22%, followed by large hydro at 8% and geothermal at 4%. Add in minor contributions from biomass, biogas and small hydro projects, and the total renewable percentage for the day was 61%.
But even on this banner day for renewables, 39% of CAISO’s demand was met by non-renewable sources. And even at the 3:35–3:40 p.m. interval when CAISO hit 97% non-hydro renewables, other power plants in the state were running, including gas, nuclear and hydro facilities.
That means California still burned enough gas to meet about 15% of demand at the same moment that it had enough non-hydro renewable production to meet 97% of demand; again, the excess was exported to other states.
Adding large hydro and nuclear into the CAISO mix during the renewables peak yields a maximum of 107% carbon-free power that day, as shown in the chart below. During the three hours when clean electricity was being produced in excess of demand, California was exporting its carbon-free energy to neighboring states, almost certainly offsetting fossil power.
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