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Daniel Cohan Profile picture
Daniel Cohan
@cohan_ds
Atmospheric scientist and associate professor of environmental engineering at Rice University; Author of Confronting Climate Gridlock (Yale Univ Press, 2022)
Dec 20, 2022 • 5 tweets • 3 min read
While we agree that the Texas grid can probably handle this week's freeze, I differed with another expert on whether ERCOT could handle a repeat of the February 2021 freeze. Here's why (short 🧵)
abc13.com/ercot-arctic-b… From ERCOT's own seasonal assessment, supply would fall >7 GW short of demand if merely "high" peak load coincided with high outages and low winds (last column). But Feb 2021 likely topped ERCOT's "extreme" load case (73 GW) by several GW. eia.gov/todayinenergy/…
Mar 4, 2022 • 25 tweets • 12 min read
The role of geothermal is something I grappled with a lot in researching the book. I came to see enhanced geothermal as potentially pivotal to decarbonizing electricity, and a technology that should be a top priority for RD&D funding. Here's why... 🧵 (1/) For now, geothermal is a minuscule share even among U.S. renewable energy sources, and one that's barely growing and confined to a narrow region.
eia.gov/todayinenergy/…
Jul 8, 2021 • 11 tweets • 5 min read
Why ERCOT had a close call June 14-16:
1. Demand high for June (70 GW; T in 90s), but not for summer peak (expected ~77 GW, or 80+GW in heat wave)
2. Winds very slow
3. Thermal power plant outages higher than expected (~15% of 64 GW fleet) throughout month
4. Solar kept lights on Thermal and total unplanned resource outages in ERCOT, June Electricity demand in ERCOT, June 2021, from EIA Hourly GridERCOT power output by source, from EIA Hourly Grid Monitor ERCOT's summer assessment of resource adequacy unrealistically expects to get 95% output from its 64 GW thermal fleet during summer peak demand. But outages have stayed ~10-15+%, and output is often below 90% even at plants that don't report outages.
Jul 7, 2021 • 9 tweets • 2 min read
Governor Abbott’s letter to the PUC will actually make Texas electricity costlier and less reliable, while skewing the playing field to favor aging thermal power plants over new renewables. Here’s why… 🧵
texastribune.org/2021/07/06/tex… 1. Abbott wants subsidies for development & maintenance of coal, nuclear & gas plants. But no one wants to build costly new coal & nuclear. Better maintenance is indeed needed as thermal plants suffer 3x expected outages; that’s a cost of doing business, not cause for subsidies.
Jun 16, 2021 • 5 tweets • 3 min read
ERCOT debuted "extreme scenarios" in its summer SARA, but downplayed them without justification as "1-in-100" events. In fact, power plant outages are double their worst case and wind output low. Solar has saved us this week, but the grid seems unready for an August heat wave. It also seems erroneous to call Uri a one-in-100 event, as shown in this research by my colleague Prof. James Doss-Gollin @jdossgollin
iopscience.iop.org/article/10.108…
cee.rice.edu/news/was-febru…
Jun 13, 2021 • 4 tweets • 2 min read
Solar keeping the lights on in ERCOT today. Unusually tight and pricy for a warm but unexceptional June weekend afternoon, with winds slow. ImageImageImage I’m seeing tweets of brief power outages in parts of Texas today as supply got tight and prices spiked. Does anyone have details on that?
Apr 13, 2021 • 9 tweets • 5 min read
Back near $2,000/MWh on a mild spring day, with many of our power plants down for maintenance Awfully tight for a mild spring day
Mar 30, 2021 • 4 tweets • 2 min read
Article leads with two companies that went bust, before eventually noting that DOE loan guarantees netted a $2B profit, funded Tesla and other successes, and brought down the costs of solar, wind, and EVs. Sounds like a success to me. nytimes.com/2021/03/29/cli… So Obama’s program netted $2B, helped turn wind and solar into thriving industries, boosted Tesla and EVs, and created jobs, but it's called "not particularly effective?” Sounds like a success worth emulating, rather than focusing on “Solyndra syndrome” yet again.
Feb 17, 2021 • 31 tweets • 10 min read
So many of the misleading narratives about the #TexasBlackout are missing a fundamental understanding of our electric power supply, and its mutual vulnerabilities with our gas systems. We're facing an _energy systems_ crisis, not just an electricity crisis. To understand why, we can begin by seeing how ERCOT generates power on average. Nearly half is from gas. Wind topped coal last year for the first time. We have just 4 nuclear units, little hydro, and solar soaring from a small base.
Feb 16, 2021 • 4 tweets • 2 min read
Wind has been producing ~1.5 GW less than ERCOT expected for a winter peak event, solar ~1 GW more than expected, & nuclear running 100%. Meanwhile, >30 GW of fossil plants, mostly natural gas, went down. So of course the narrative is -- frozen wind turbines! 🤦‍♂️
#RollingBlackouts See here for more details
#TexasFreeze #RollingBlackouts
Feb 15, 2021 • 11 tweets • 6 min read
ERCOT expected to get low capacity factors from wind and solar during winter peak demand. What it didn't expect is >20 GW of outages from thermal (mostly natural gas) power plants.
ercot.com/gridinfo/resou…
#TexasFreeze #RollingBlackouts Note that ERCOT's worst case scenario, based on 2011 freeze, included 9,509 MW of outages, not the >20,000 MW that's down today. Much deeper freeze this time, and natural gas is scarce given heating needs.
ercot.com/content/wcm/li…
Feb 1, 2020 • 18 tweets • 8 min read
Following up on last year's thread, time to look at Annual Energy Outlook 2020, released by EIA Wednesday: eia.gov/outlooks/aeo/ A huge step forward this year is considering alternate cases for renewables costs. As I wrote last year, the lack of such scenarios had been a persistent blindspot in EIA outlooks. Thank you EIA!!
thehill.com/opinion/energy…
Dec 29, 2019 • 11 tweets • 2 min read
After a not too bad track record the past two years, might as well make some predictions for 2020 on climate, energy, and related matters.
Predictions for 2020 on climate, energy & related matters.
1. A moderate Democrat is elected President, Ds hold House, but Rs keep Senate