Kevin J. Kircher @kevinjkircher.com · 26/09/2026One cool thing about ebikes? They make active transit way more accessible. I shredded my knees through high-impact athletics in my teens/20s, to the point where riding a non-e bike up a steep hill is awful. With an ebike, though, hills are no problem! 915112
Kevin J. Kircher @kevinjkircher.com · 24/09/2026Talked about heat pumps today with a bunch of awesome home energy auditors/consultants who help Indiana rural electric co-op members save money on bills. Here's my TL;DR slide on household HVAC economics. 37715
Kevin J. Kircher @kevinjkircher.com · 16/09/2026Only about 12% of the corn (1/5 of us cropland) grown in the US is actual food for humans - 40% goes to ethanol, 40% to animal feed, etc. - and much of that 12% is high-fructose corn syrup and other things that are... yeah, not great to eat. www.ers.usda.gov/topics/crops... 000
Kevin J. Kircher @kevinjkircher.com · 01/09/2026Air-source heat pumps - efficient electric heating/cooling machines - have outsold gas furnaces for US residential space heating since 2021. Annual ASHP sales have grown 90% since 2004 are now 53% of new residential heating equipment sales. Data and plot from RMI: rmi.org/resources/tr... 24011
Kevin J. Kircher @kevinjkircher.com · 10/08/2026Congress will soon vote on energy permitting. To evaluate the bill's potential impacts, it helps to understand what energy infrastructure people are trying to build. I wrote a bit about what we can learn from the Mid-Atlantic grid's updated interconnection queue: kevinjkircher.com/what-energy-... 1146
Kevin J. Kircher @kevinjkircher.com · 22/07/2026All US economic sectors emitted more carbon dioxide from energy use in 2025 than in 2024, according the the latest Energy Information Administration report. www.eia.gov/environment/... 1137
Kevin J. Kircher @kevinjkircher.com · 03/07/2026This is EPA data, which undercounts methane emissions from oil and gas and converts CH4 to CO2e using an outdated 100-year GWP of 28. Texas has a LOT of leaky oil and gas wells, pipelines, and other infrastructure, so its true emissions are likely far higher. kevinjkircher.com/wp-content/u... 160
Kevin J. Kircher @kevinjkircher.com · 03/07/2026Yes, and Texas' electricity is its climate success story, at least relative to other sectors. TX economy-wide emissions are 7% higher than 2005 levels and 17% higher than 1990 levels. Power sector is making some progress, other sectors are not, on balance TX is harming the climate more each year. 1163
Kevin J. Kircher @kevinjkircher.com · 30/06/2026The ideal DC configuration reduced annual net energy bills by 16.7% relative to the AC configuration. The non-ideal DC configuration reduced bills by 12.5%. Those percent savings are pretty good - it's not easy to improve equipment energy efficiency by ~15%! - but the $ savings were only ~$60/yr. 1221
Kevin J. Kircher @kevinjkircher.com · 30/06/2026We modeled real-time performance over a year in NW Indiana, which sees cold winters and hot summers. We modeled net metering, where summer power exports from the house to the grid offset winter power imports (to a degree). Bills were highest (and export credits lowest) in today's AC configuration. 1180
Kevin J. Kircher @kevinjkircher.com · 30/06/2026We then used data from performance testing, as well as solar and load data from our test house, to model different power distribution configurations connecting solar photovoltaics, a stationary battery, and a heat pump (which uses ~70% of our all-electric Indiana test house's annual energy). 1191
Kevin J. Kircher @kevinjkircher.com · 30/06/2026New paper! Housing increasingly has big devices that run natively on Direct Current (solar panels, EVs, batteries, motors on heat pumps and air conditioners, etc). What if we connected them on DC, rather than today's AC distribution + lossy AC/DC conversions? 🧵 www.sciencedirect.com/science/arti... 1316548
Kevin J. Kircher @kevinjkircher.com · 26/06/2026The scientists involved are smart people who recognize the risk of oil and gas funders corrupting the research. However, as the Pacala quote below shows, they can also be overconfident in their own ability to resist that corruption. Research has shown that few of us are, in fact, resistant. 2132
Kevin J. Kircher @kevinjkircher.com · 23/06/2026Dense housing is necessary but insufficient for good neighborhoods. This new apartment building will add a couple hundred beds - great! - but every window overlooks at least 4 lanes of fast traffic, including semis. Noise, air pollution, poor walkability and wheelchairability, poor transit access. 5485
Kevin J. Kircher @kevinjkircher.com · 13/06/2026Hopefully we can all stop talking about abundance now that we know the "movement" has been co-opted by a bunch of Silicon Valley billionaires, crypto bros, and Trump donors, to the tune of at least a quarter-billion per year in funding. prospect.org/2026/06/12/n... 1247
Kevin J. Kircher @kevinjkircher.com · 10/06/2026Keep eyes on prize, m'dudes. Red line basically flat. Red line gotta go to zero. 3110
Kevin J. Kircher @kevinjkircher.com · 17/05/2026None of this is forever. On #1, US LNG export capacity is expected to double in the next five years. On #2, winter is coming, my sweet summer child. On #3, see #1. 240
Kevin J. Kircher @kevinjkircher.com · 17/05/2026What's your favorite explanation of why US domestic natural gas prices have stayed fairly stable despite the Iran war, even as gasoline and diesel prices have skyrocketed? (For context, the Iran war shut down about 20% of global oil supply and about 20% of global liquified natural gas supply.) 470
Kevin J. Kircher @kevinjkircher.com · 17/05/2026Oil and gas companies have made some $50 billion in windfall profit since Trump started the Iran war. These profits come mainly from higher gasoline and diesel prices most people pay and go mainly to the owners and major shareholders of oil and gas companies, who are already very rich. 32513
Kevin J. Kircher @kevinjkircher.com · 15/05/2026One cool thing about heat pumps: The heat they provide is at least ~2/3 renewable, regardless of the electricity source. (Note the circular flow between the indoors and outdoors.) If the power source is renewable, then the system operation is 100% renewable, although manufacturing generally is not. 213326
Kevin J. Kircher @kevinjkircher.com · 15/05/20265 million households in the Northeast burn heating oil to heat space or water. Due to Trump's Iran war, heating oil prices are up 60% over last year. Risks are high of more severe price spikes this fall/winter. These households should switch to electric heat pumps this summer. States should help. 84220
Kevin J. Kircher @kevinjkircher.com · 08/05/2026Here is the CO2 emission intensity of electricity in Texas and California, in grams of CO2 per kWh generated. Texas electricity in 2024 was dirtier than California electricity in 1990. Texas electricity in 2024 was, on average, no better than a grid run entirely on natural gas combined cycle plants. 34515
Kevin J. Kircher @kevinjkircher.com · 08/05/2026In 2024, the Texas electricity sector emitted 5.4 times more climate pollution than the California electricity sector. Per-capita 2024 electricity emissions in TX were 6.7 times higher than in CA. Electricity in Texas is getting better, but it's still godawful. Don't confuse rates with magnitudes. 27626
Kevin J. Kircher @kevinjkircher.com · 08/04/2026Whatever opinions you might have about global warming potentials, I don't think "different mitigation targets for different gases" gets around the basic problem of having to make a value-based judgment on the exchange rate between CO2 and CH4 (or other short-lived greenhouse gases). Quick 🧵 on why. 54410
Kevin J. Kircher @kevinjkircher.com · 07/04/2026Spring on the Wabash. Crisp but sunny walk to work today 180
Kevin J. Kircher @kevinjkircher.com · 21/03/2026One in five households in New York State heats with propane or oil. Those prices are up 30% and 40%, respectively, from this time last year due to Trump's Iran war. At these prices, switching to electric heat pumps could cut heating bills *in half*. www.nyserda.ny.gov/Energy-Price... 411441
Kevin J. Kircher @kevinjkircher.com · 21/03/2026To see the difference between the 20- and 100-year horizons, check out this graph from my 2025 paper. The solid red curve is my estimate of net US greenhouse gas emissions with CH4 from oil and gas systems assessed over 100 years. The dashed red curve uses 20 years: Way higher than the solid red. 1123
Kevin J. Kircher @kevinjkircher.com · 15/03/2026The new paper "Why Biden-era clean energy investment policies had limited political returns" by @agazmararian.bsky.social, @natemjensen.bsky.social and @dustintingley.bsky.social has great data, but it's wild in a paper about messaging and information environments to... www.pnas.org/doi/10.1073/... 1349
Kevin J. Kircher @kevinjkircher.com · 15/03/2026Americans in both parties long viewed solar energy more favorably than any other energy source. Solar favorability among Republicans dropped a lot in recent years, due part to opinion-shaping by right-wing media. Bundling solar with data centers, which are pretty unpopular, probably doesn't help. 76514
Kevin J. Kircher @kevinjkircher.com · 13/03/2026I knew municipal utilities generally provide lower electricity prices than investor-owned monopoly utilities, but I had no idea the difference was *this stark* in California. No wonder CA electeds are pushing to make municipalization easier and cheaper. energyathaas.wordpress.com/2026/03/09/t... 117330
Kevin J. Kircher @kevinjkircher.com · 10/03/2026Saw 5 bald eagles fishing as I crossed the Wabash on my way to work this morning and look they're not even bald (that's vultures), their main feature is big white butts. Our national bird is the white-butt eagle 2200
Kevin J. Kircher @kevinjkircher.com · 09/03/2026"TAE is a very curious fusion company: It has promised that its fusion power plant is just over the horizon for over 25 years." www.fusionconclusion.com/how-taes-fus... 156314
Kevin J. Kircher @kevinjkircher.com · 04/03/2026Assuming a 30-min commute to/from train station, 45-min to/from airport, 30-min early arrival for train and 90-min for plane, 500 mph plane (LAX-JFK is ~450), a 280 mph train is faster than flying any distance less than 950 miles. Here is a 950-mile radius circle centered on Kansas City. 35814
Kevin J. Kircher @kevinjkircher.com · 02/03/2026Raw data source: Table 1.1 from www.eia.gov/electricity/... 010
Kevin J. Kircher @kevinjkircher.com · 02/03/2026US electricity generation changes, 2024 ➡️ 2025: Coal: ⬆️ 67 TWh (13%) Oil: ⬆️ 2 TWh (19%) Gas: ⬇️ 41 TWh (-4%) Nuclear: no change Hydro: ⬆️ 6 TWh (3%) Other renewables: ⬆️ 13 TWh (11%) Total: ⬆️ 47 TWh (2%) Big story is coal generation rising A LOT (67 TWh, 5x renewable growth), mostly displacing gas. 64918
Kevin J. Kircher @kevinjkircher.com · 01/03/2026(Background for others: The new report suggests six ways to revise Sankey diagrams to highlight how much fossil energy ends up as waste heat, to distinguish electrons from molecules, and to shift the focus from primary energy supply [very fossil-heavy] to the actual useful things we do with energy.) 2161
Kevin J. Kircher @kevinjkircher.com · 21/02/2026The incredible students in the Sustainable Energy Club of Purdue put together an awesome conference this weekend! Tons of talks by students, profs, community organizations, and companies. I had fun giving the kickoff talk! 1121
Kevin J. Kircher @kevinjkircher.com · 18/02/2026Awkward, but... probably the most effective policy to make US energy more affordable is just to return oil and gas export rules to their pre-Obama states. This would reduce gasoline and natural gas prices, as well as wholesale electricity prices, which natural gas power plants very often set. 1128
Kevin J. Kircher @kevinjkircher.com · 16/02/2026I'll talk with @jaimepalter.bsky.social and @jfrancisclimate.bsky.social Wed at 1 ET, hosted by the Solutions Journalism Network and URI. How is climate change affecting winter weather extremes? How we can improve resilience to winter storms? Intended for climate journalists but all are welcome. 163
Kevin J. Kircher @kevinjkircher.com · 14/02/2026The United States uses about twice as much energy per person as Switzerland or the UK. The US also has worse public health and life expectancy. Few countries use more energy per person than the US. Most of them are, like the US, petrostates. 816266
Kevin J. Kircher @kevinjkircher.com · 08/02/2026Energy geeks, please put on your quibble hats, prepare your hair splitters, and get ready to pick some nits! What do you think about this slide from my upcoming lecture on solar energy? 24425
Kevin J. Kircher @kevinjkircher.com · 01/02/2026i just invented a heat pump that works down to -250 C and is perfectly immune to frost buildup on outdoor coils (it has no outdoor coils) (don't ask me about the COP) 070
Kevin J. Kircher @kevinjkircher.com · 28/01/2026Not a policy proposal, just showing the potential of redistribution: The mean net worth per household in the US is $1.3 million. The bottom 50% have $63.4k per household on average. Redistributing net worth to the mean would increase 68 million households' net worth by $1.2 million on average. 130
Kevin J. Kircher @kevinjkircher.com · 19/01/2026This chart by @nathanielbullard.com is one reason data centers are driving up our electricity prices. Tech companies usually build data centers close to cities, where accommodating their GW-scale power demand entails costly reinforcement of wires or transformers. Utilities pass those costs on to us. 741460626
Kevin J. Kircher @kevinjkircher.com · 13/01/2026Fine-particulate and ozone air pollution from fossil fuels causes 4-6 million avoidable deaths per year: 7-10% of all deaths worldwide. At an ~$11 million statistical value of life, this is a 44-66 trillion $/yr (38-56% of ~117 T$/yr global GDP) cost that appears nowhere in fossil fuel economics. 25632
Kevin J. Kircher @kevinjkircher.com · 13/01/2026Saw four bald eagles while walking to work on the first day of class. Not sure whether this is an auspicious or ominous sign. 3152
Kevin J. Kircher @kevinjkircher.com · 20/12/2025The wealthiest 10% of humans emit ~47% or ~77% of global greenhouse gases annually, depending on whether emissions are allocated based on consumption of emissions-intensive goods and services on on ownership of polluting assets. wir2026.wid.world/insight/exec... 44927