Brian Siana
@briansiana.bsky.social
Astronomy Professor at UC Riverside / Vice Chair of the Riverside Board of Public Utilities / Heat pump evangelist
The high-electricity-demand season in California is over. For the 3rd year in a row, CA has issued ZERO Flex Alerts (call for voluntary conservation when demand approaches supply), a first since Flex Alerts were created 25 years ago. And the primary reason is ... batteries. 🔌💡
September 29, 2025 at 6:45 PM
The high-electricity-demand season in California is over. For the 3rd year in a row, CA has issued ZERO Flex Alerts (call for voluntary conservation when demand approaches supply), a first since Flex Alerts were created 25 years ago. And the primary reason is ... batteries. 🔌💡
Figures from @planetarysociety.bsky.social demonstrating the enormity of the proposed NASA budget cut. NASA science will be cut in half.
Similarly devastating cuts at NSF, DOE, NOAA, etc.
More here: www.planetary.org/articles/nas...
Similarly devastating cuts at NSF, DOE, NOAA, etc.
More here: www.planetary.org/articles/nas...
June 27, 2025 at 4:34 AM
Figures from @planetarysociety.bsky.social demonstrating the enormity of the proposed NASA budget cut. NASA science will be cut in half.
Similarly devastating cuts at NSF, DOE, NOAA, etc.
More here: www.planetary.org/articles/nas...
Similarly devastating cuts at NSF, DOE, NOAA, etc.
More here: www.planetary.org/articles/nas...
It’s pretty wild that even on a really hot day yesterday, batteries were the largest source of power on the CA grid for a couple of hours. This has become pretty common this Spring. 🔌💡
June 18, 2025 at 1:50 AM
It’s pretty wild that even on a really hot day yesterday, batteries were the largest source of power on the CA grid for a couple of hours. This has become pretty common this Spring. 🔌💡
Yesterday at 7:45pm, the California grid was supplying 10.03 GW of power from batteries, equivalent to the typical power consumption of ~10 million American homes. For 1.5 hours, batteries were the largest supplier of power in the state.
May 21, 2025 at 4:56 PM
Yesterday at 7:45pm, the California grid was supplying 10.03 GW of power from batteries, equivalent to the typical power consumption of ~10 million American homes. For 1.5 hours, batteries were the largest supplier of power in the state.
Not sure how gross would be calculated in this case, but net load at the time was -3 GW. So definitely not net!
March 8, 2025 at 3:17 AM
Not sure how gross would be calculated in this case, but net load at the time was -3 GW. So definitely not net!
Yeah, >100% if you do the accounting a different way. All of our load could be met by renewables currently, but we’re still running a bit of gas (and exporting some).
March 7, 2025 at 9:19 PM
Yeah, >100% if you do the accounting a different way. All of our load could be met by renewables currently, but we’re still running a bit of gas (and exporting some).
California hit a new battery storage record of 8.46 GW, which was 35% of the entire load at the time!!
🔌💡
🔌💡
March 7, 2025 at 9:03 PM
California hit a new battery storage record of 8.46 GW, which was 35% of the entire load at the time!!
🔌💡
🔌💡
California CO2 emissions from electricity have fallen 41% in the last ten years, all while adding more than 2 million EVs and (very slowly) starting to replace gas furnaces with electric heat pumps.
Data from CAISO: www.caiso.com/todays-outlo...
Data from CAISO: www.caiso.com/todays-outlo...
March 5, 2025 at 11:32 PM
California CO2 emissions from electricity have fallen 41% in the last ten years, all while adding more than 2 million EVs and (very slowly) starting to replace gas furnaces with electric heat pumps.
Data from CAISO: www.caiso.com/todays-outlo...
Data from CAISO: www.caiso.com/todays-outlo...
After 12 years, our solar panel production has degraded by 0.76%/year. There's a 2.2% variation around the trend, due to weather. Including that variance, the trend is significant at 4 sigma. The panels are at ~92% of original efficiency and will be at ~85%, 25 years after installation. 🔌💡
January 6, 2025 at 6:01 PM
After 12 years, our solar panel production has degraded by 0.76%/year. There's a 2.2% variation around the trend, due to weather. Including that variance, the trend is significant at 4 sigma. The panels are at ~92% of original efficiency and will be at ~85%, 25 years after installation. 🔌💡
It is so incredibly cool that I can charge our vehicle for the week, heat our home, and bake holiday cookies with ~free and clean electricity (solar that would otherwise be curtailed), and near the Winter Solstice!!!
December 15, 2024 at 6:16 PM
It is so incredibly cool that I can charge our vehicle for the week, heat our home, and bake holiday cookies with ~free and clean electricity (solar that would otherwise be curtailed), and near the Winter Solstice!!!
This information was in CAISO's monthly "Key Statistics."
www.caiso.com/documents/ke...
CA demand is ~30-40 GW (up to 50 GW). The batteries are currently soaking up ~7 GW of solar power during the day, and discharging in the evening to prevent gas peaker plants from turning on.
www.caiso.com/documents/ke...
CA demand is ~30-40 GW (up to 50 GW). The batteries are currently soaking up ~7 GW of solar power during the day, and discharging in the evening to prevent gas peaker plants from turning on.
October 11, 2024 at 7:25 PM
This information was in CAISO's monthly "Key Statistics."
www.caiso.com/documents/ke...
CA demand is ~30-40 GW (up to 50 GW). The batteries are currently soaking up ~7 GW of solar power during the day, and discharging in the evening to prevent gas peaker plants from turning on.
www.caiso.com/documents/ke...
CA demand is ~30-40 GW (up to 50 GW). The batteries are currently soaking up ~7 GW of solar power during the day, and discharging in the evening to prevent gas peaker plants from turning on.
Sometime last month, CA hit 10 GW (~40 GWh) of battery storage on its grid (not including behind-the-meter batteries).
It's causing extraordinary changes on the grid, in terms of emissions, pricing, promotion of additional renewables, reliability. A pretty incredible transformation. 🔌💡
It's causing extraordinary changes on the grid, in terms of emissions, pricing, promotion of additional renewables, reliability. A pretty incredible transformation. 🔌💡
October 11, 2024 at 3:56 PM
Sometime last month, CA hit 10 GW (~40 GWh) of battery storage on its grid (not including behind-the-meter batteries).
It's causing extraordinary changes on the grid, in terms of emissions, pricing, promotion of additional renewables, reliability. A pretty incredible transformation. 🔌💡
It's causing extraordinary changes on the grid, in terms of emissions, pricing, promotion of additional renewables, reliability. A pretty incredible transformation. 🔌💡
Ha! The night sky is pretty faint! But on the plus side, its spectrum is almost perfectly optimized for Silicon photovoltaics, rising at longer wavelengths, right up to the Si band gap. I suspect we could get >40% efficiency.
September 28, 2024 at 3:55 AM
Ha! The night sky is pretty faint! But on the plus side, its spectrum is almost perfectly optimized for Silicon photovoltaics, rising at longer wavelengths, right up to the Si band gap. I suspect we could get >40% efficiency.
After 5 years/60,000 miles with our EV (Hyundai Kona Electric), we averaged 4.5 mi/kWh, an efficiency equivalent to MPGe = 152 mi/gal. The gas Kona gets a combined EPA 32 mpg. Even accounting for the fact that I drive conservatively, electric is still 4x more efficient than the gas equivalent. 🔌💡
September 26, 2024 at 4:44 PM
After 5 years/60,000 miles with our EV (Hyundai Kona Electric), we averaged 4.5 mi/kWh, an efficiency equivalent to MPGe = 152 mi/gal. The gas Kona gets a combined EPA 32 mpg. Even accounting for the fact that I drive conservatively, electric is still 4x more efficient than the gas equivalent. 🔌💡
And the 86 GW number is already crazy. The comparison with CA doesn't give the full picture. Peak demand in CA basically hasn't changed in 20 years. It's been steadily rising in TX and dramatically so in the last couple.
September 19, 2024 at 5:52 PM
And the 86 GW number is already crazy. The comparison with CA doesn't give the full picture. Peak demand in CA basically hasn't changed in 20 years. It's been steadily rising in TX and dramatically so in the last couple.
You can cancel your NY Times subscription. But there's an intermediate option too.
A month after I cancelled (and answered that it was due to cost), I was offered a $1/week all-access rate for 6 months. I held out, and they offered a full year.
Seems like others could use this information.
A month after I cancelled (and answered that it was due to cost), I was offered a $1/week all-access rate for 6 months. I held out, and they offered a full year.
Seems like others could use this information.
August 26, 2024 at 6:30 PM
You can cancel your NY Times subscription. But there's an intermediate option too.
A month after I cancelled (and answered that it was due to cost), I was offered a $1/week all-access rate for 6 months. I held out, and they offered a full year.
Seems like others could use this information.
A month after I cancelled (and answered that it was due to cost), I was offered a $1/week all-access rate for 6 months. I held out, and they offered a full year.
Seems like others could use this information.
Negative electricity prices in California in … August. Weird.
This happens a LOT now all spring, and increasingly in the winter, when the demand is basically being met by renewables. It’s happening today because demand is exceptionally low (it’s a weekend and abnormally —> low A/C).
This happens a LOT now all spring, and increasingly in the winter, when the demand is basically being met by renewables. It’s happening today because demand is exceptionally low (it’s a weekend and abnormally —> low A/C).
August 25, 2024 at 7:34 PM
Negative electricity prices in California in … August. Weird.
This happens a LOT now all spring, and increasingly in the winter, when the demand is basically being met by renewables. It’s happening today because demand is exceptionally low (it’s a weekend and abnormally —> low A/C).
This happens a LOT now all spring, and increasingly in the winter, when the demand is basically being met by renewables. It’s happening today because demand is exceptionally low (it’s a weekend and abnormally —> low A/C).
“Trimble insists that she had fun and she always felt empowered, not despite the power imbalances but because she learned to use them in her favor.”
August 14, 2024 at 3:27 PM
“Trimble insists that she had fun and she always felt empowered, not despite the power imbalances but because she learned to use them in her favor.”
2. The Flex Alert website lists things you can do to reduce demand during Flex Alerts, and "don't charge your electric vehicle" isn't listed. This is by far the most important thing. It should be in huge, blinking red text at the top of the page. It's more important than everything else listed.
June 27, 2024 at 7:38 PM
2. The Flex Alert website lists things you can do to reduce demand during Flex Alerts, and "don't charge your electric vehicle" isn't listed. This is by far the most important thing. It should be in huge, blinking red text at the top of the page. It's more important than everything else listed.
1. I'm still really surprised that the standard Flex Alert time is 4-9pm. Due to increased solar, the peak net demand has shifted later in the evening. Here is net demand (purple) on Monday afternoon. The net demand peak is ~8pm and the evening ramp doesn't start until 6!!
June 27, 2024 at 7:33 PM
1. I'm still really surprised that the standard Flex Alert time is 4-9pm. Due to increased solar, the peak net demand has shifted later in the evening. Here is net demand (purple) on Monday afternoon. The net demand peak is ~8pm and the evening ramp doesn't start until 6!!
98% of surveyed members of the American Astronomical Society expressed concern about climate change. Of the 4600 tons of CO2 emitted annually due to AAS activities, 84% is due to conferences.
Inevitable conclusion that nobody wants to hear... we should be flying less.
arxiv.org/abs/2406.10451
Inevitable conclusion that nobody wants to hear... we should be flying less.
arxiv.org/abs/2406.10451
June 21, 2024 at 11:00 PM
98% of surveyed members of the American Astronomical Society expressed concern about climate change. Of the 4600 tons of CO2 emitted annually due to AAS activities, 84% is due to conferences.
Inevitable conclusion that nobody wants to hear... we should be flying less.
arxiv.org/abs/2406.10451
Inevitable conclusion that nobody wants to hear... we should be flying less.
arxiv.org/abs/2406.10451
Not really! Prices have been negative during the day nearly every day for the last 5 months, and especially on weekends. I only need to charge ~8 hours/week. Pretty easy to do on the weekend and/or a cooler weekday.
June 20, 2024 at 5:41 PM
Not really! Prices have been negative during the day nearly every day for the last 5 months, and especially on weekends. I only need to charge ~8 hours/week. Pretty easy to do on the weekend and/or a cooler weekday.
Continuing my 5 month streak of only charging the car when electricity prices in SoCal are negative. This means that the marginal demand increase to charge my EV is likely met with what would’ve otherwise been curtailed solar power. Cleanest energy possible. 🔌💡
June 19, 2024 at 5:57 PM
Continuing my 5 month streak of only charging the car when electricity prices in SoCal are negative. This means that the marginal demand increase to charge my EV is likely met with what would’ve otherwise been curtailed solar power. Cleanest energy possible. 🔌💡
One of my favorite recent traditions is getting our family’s annual America the Beautiful pass to National Parks ( @officialnps.bsky.social ) and federal recreation land in the mail. Grateful for these preserved lands and their stewards. This weekend, we start with Kings Canyon NP.
May 22, 2024 at 7:06 PM
One of my favorite recent traditions is getting our family’s annual America the Beautiful pass to National Parks ( @officialnps.bsky.social ) and federal recreation land in the mail. Grateful for these preserved lands and their stewards. This weekend, we start with Kings Canyon NP.