Greg Schivley
@gschivley.bsky.social
Energy systems data, code, hiking, bikes, and more. Building stuff in the ZERO Lab at Princeton.
My new favorite bathroom sign
October 17, 2025 at 1:16 PM
My new favorite bathroom sign
X1 TLR here, not that I know the difference. More that I needed something wider (40mm) and with some tread for rides on rail trails with my daughter on the back.
October 5, 2025 at 12:27 AM
X1 TLR here, not that I know the difference. More that I needed something wider (40mm) and with some tread for rides on rail trails with my daughter on the back.
Apparently EIA's method results in an over-smoothed distribution of energy across the year, especially for smaller dams. Figure from an earlier paper by the same authors showing how Hoover and Glen Canyon profiles are applied to other dams in the region.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
September 3, 2025 at 7:50 PM
Apparently EIA's method results in an over-smoothed distribution of energy across the year, especially for smaller dams. Figure from an earlier paper by the same authors showing how Hoover and Glen Canyon profiles are applied to other dams in the region.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Living the dream. All 6 of biked to the beach!
August 27, 2025 at 12:09 AM
Living the dream. All 6 of biked to the beach!
I'm digging into the EIA 860 Energy Storage file, where there are a bunch of columns that describe its application (arbitrage, frequency reg, backup power, etc). Values are "Y" or "PR". But PR isn't described anywhere!
After some digging, I'm pretty sure that PR is "primary".
You're welcome.
After some digging, I'm pretty sure that PR is "primary".
You're welcome.
July 23, 2025 at 7:23 PM
I'm digging into the EIA 860 Energy Storage file, where there are a bunch of columns that describe its application (arbitrage, frequency reg, backup power, etc). Values are "Y" or "PR". But PR isn't described anywhere!
After some digging, I'm pretty sure that PR is "primary".
You're welcome.
After some digging, I'm pretty sure that PR is "primary".
You're welcome.
It’s helpful to remember that not everything in the world is turning to shit. Last week my family went to Banff, which was absolutely incredible. Thanks Canada, for working to keep it wild.
July 3, 2025 at 8:10 PM
It’s helpful to remember that not everything in the world is turning to shit. Last week my family went to Banff, which was absolutely incredible. Thanks Canada, for working to keep it wild.
The annual capex is probably a smoothed version of maintenance/capital costs over the life of a plant that are needed to keep it running.
May 28, 2025 at 2:08 PM
The annual capex is probably a smoothed version of maintenance/capital costs over the life of a plant that are needed to keep it running.
I had the same question since we usually lump annual capex with FOM in energy system models. According to ChatGPT it's mostly about accounting. O&M is recorded as expenses in the period they occur. Capex is for assets on the balance sheet and depreciated over time.
May 28, 2025 at 2:08 PM
I had the same question since we usually lump annual capex with FOM in energy system models. According to ChatGPT it's mostly about accounting. O&M is recorded as expenses in the period they occur. Capex is for assets on the balance sheet and depreciated over time.
Long before EIA had an open NEMS GitHub repo, I started using a 2019 AEO report on existing generator O&M costs. It splits plants into a few cost bins by size. Turns out EIA doesn't use those values! In an addendum they say plants are split into further subgroups. 1/n
www.eia.gov/analysis/stu...
www.eia.gov/analysis/stu...
May 27, 2025 at 7:28 PM
Long before EIA had an open NEMS GitHub repo, I started using a 2019 AEO report on existing generator O&M costs. It splits plants into a few cost bins by size. Turns out EIA doesn't use those values! In an addendum they say plants are split into further subgroups. 1/n
www.eia.gov/analysis/stu...
www.eia.gov/analysis/stu...
AEO 2025 was released in April and I wanted to see if coal prices for electric power changed from 2023. The 2023 prices were lower than observed prices in some regions and led models to run coal at high CFs.
Good news--prices start ⬆️! Then they crater as NEMS retires nearly *all* coal capacity. 1/3
Good news--prices start ⬆️! Then they crater as NEMS retires nearly *all* coal capacity. 1/3
May 7, 2025 at 4:46 PM
AEO 2025 was released in April and I wanted to see if coal prices for electric power changed from 2023. The 2023 prices were lower than observed prices in some regions and led models to run coal at high CFs.
Good news--prices start ⬆️! Then they crater as NEMS retires nearly *all* coal capacity. 1/3
Good news--prices start ⬆️! Then they crater as NEMS retires nearly *all* coal capacity. 1/3
Yep! Gonna assume you didn’t figure that one out from Slack. Nice job 👍
April 9, 2025 at 11:49 AM
Yep! Gonna assume you didn’t figure that one out from Slack. Nice job 👍
Name that national lab. Just a short hike from the lab to this view.
April 8, 2025 at 9:03 PM
Name that national lab. Just a short hike from the lab to this view.
Name that national lab. Hard level.
April 8, 2025 at 2:10 PM
Name that national lab. Hard level.
10 years ago, face tracking and mood detection was university level research. Now it's showing up in elementary school STEM fairs with visual programming. 🤯
March 20, 2025 at 1:34 PM
10 years ago, face tracking and mood detection was university level research. Now it's showing up in elementary school STEM fairs with visual programming. 🤯
Interesting. I tried the same model and it refused to answer the first time. Then using distill qwen 1.5B as a draft model it gave me a Chinese politically correct answer. I tried one last time without a draft model and it decided that declining to answer a second time wasn't going to work 😂
February 21, 2025 at 7:02 PM
Interesting. I tried the same model and it refused to answer the first time. Then using distill qwen 1.5B as a draft model it gave me a Chinese politically correct answer. I tried one last time without a draft model and it decided that declining to answer a second time wasn't going to work 😂
It’s looking like high wind conditions in the house today!
January 28, 2025 at 3:17 PM
It’s looking like high wind conditions in the house today!
Had a great trip to Gliwice, Poland to help the local team kick off their next phase of a net-zero Poland study. They have a great set of institutions working together on this and I can’t wait to see the final results.
December 19, 2024 at 3:12 AM
Had a great trip to Gliwice, Poland to help the local team kick off their next phase of a net-zero Poland study. They have a great set of institutions working together on this and I can’t wait to see the final results.
Bummed that I’m not about to get on the Star Wars plane
December 16, 2024 at 10:18 AM
Bummed that I’m not about to get on the Star Wars plane
PJM is estimating an extra 17GW of demand in 2030 over the 2024 forecast. Which was already ~10GW higher than the 2023 forecast. Things are moving fast!
November 26, 2024 at 7:31 PM
PJM is estimating an extra 17GW of demand in 2030 over the 2024 forecast. Which was already ~10GW higher than the 2023 forecast. Things are moving fast!
You can’t go wrong camping by a lake
December 27, 2023 at 3:02 PM
You can’t go wrong camping by a lake
Zip lining was just flying through clouds and imagining the trees below 😂 All the guides were saying “welcome to the rain forest!”
December 18, 2023 at 5:09 PM
Zip lining was just flying through clouds and imagining the trees below 😂 All the guides were saying “welcome to the rain forest!”
Yes, the truck/bus fumes were pretty bad.
Thanks! We were lucky to have a couple days where the volcano would peak out. The first day was more like “there’s something in that general direction.”
Thanks! We were lucky to have a couple days where the volcano would peak out. The first day was more like “there’s something in that general direction.”
December 18, 2023 at 5:05 PM
Yes, the truck/bus fumes were pretty bad.
Thanks! We were lucky to have a couple days where the volcano would peak out. The first day was more like “there’s something in that general direction.”
Thanks! We were lucky to have a couple days where the volcano would peak out. The first day was more like “there’s something in that general direction.”
And some really freaking old wind turbines!
December 18, 2023 at 3:23 PM
And some really freaking old wind turbines!
Wind, hydro, and geothermal. The energy of Costa Rica
EnergySky
EnergySky
December 18, 2023 at 3:14 PM
Wind, hydro, and geothermal. The energy of Costa Rica
EnergySky
EnergySky