Numlock News: June 17, 2026 • Batteries, Butterflies, Bonvoy

By Walt Hickey

Battery

In 2025, battery energy storage stations cost $78 per megawatt-hour generated, which is down 27 percent year over year. That is also down significantly from $185 per megawatt-hour generated in 2020, as the price of the storage batteries themselves has dropped to $70 per kilowatt-hour thanks to a surge in production by manufacturers based in China. That $78 per megawatt-hour generated is particularly significant: It means that the levelized cost of energy for battery tech is now less than OG gas-fired power plants, which came in at $102 per megawatt-hour, and is on the cusp of edging out coal’s $77 per megawatt-hour.

Mao Kawano and Koki Izumi, Nikkei Asia

Bonvoy

A group of 51 hotel owners representing about 1,000 Marriott-branded hotels are now pressing the brand to share more of the revenue reaped from the Bonvoy loyalty program with the franchisees. The program added 43 million members last year and ended the first three months of the year with 283 million members, and when those members cash in on their loyalty points, the hotels get a reimbursement from the brand that, according to the franchisees, lowballs them. Marriott makes a whole lot of money from credit cards that pay into the program, fees totaling $716 million in 2025, up from $410 million in 2019, and fee revenue is expected to increase by 35 percent to nearly $1 billion this year.

Kate King, The Wall Street Journal

Reptiles

Reptilian pets are increasing in popularity, with the number of households in the United States possessing a pet snake increasing from 810,000 in 2018 to 1.3 million in 2024. This has spurred the industry that supplies care and feeding for those snakes, and has spawned a unique form of factory farming that breeds hundreds of millions of mice and rats annually to feed them. The thing is, unlike animals raised for human food, mice and rats aren’t covered under the Animal Welfare Act, so the operations that produce them have no animal welfare oversight.

Kenny Torrella, Vox

Butterflies

A new study published in Nature Communications looks at butterflies of the Heliconius tribe; they are interesting because of their uniquely long lifespans compared to other butterflies, which tend to live for only a few weeks. Some species of Heliconius butterflies tend to live three times longer than even close relatives; for instance, Dione juno butterflies live only 14 days, but the Heliconius hewitsoni has a maximum lifespan of 348 days, nearly a year. The study suggests that the cause of that abnormally long life is that at the one species in the tribe does not show any physiological decline as it ages and delays the aging process.

Joanne Fryer, University of Bristol

FroYo

Somehow, frozen yogurt has returned: In the United States, servings of frozen yogurt rose 26 percent year over year to 87 million in the year ending March, according to Circana, driven in large part by younger consumers who presumably missed the initial two waves of frozen yogurt shops. The first was in the late 1980s and 1990s, coinciding with a number of fitness fads and a low-cal era. The second was in the 2000s when the likes of Pinkberry emerged, pushing build-your-own froyo cups, and now it appears we are once again in a froyo phase. I’m setting my calendar for the late 2030s as an ideal time to invest in a dairy.

Rainier Harris and Daniela Sirtori, Bloomberg

Justice

A new study published in Judicature finds that in general, serving on a jury makes people tend to have a better attitude towards the court system, which incidentally comes at a time when a smaller fraction of trials are actually going to jury. Survey respondents who had reported for jury service in the past five years viewed courts as more legitimate and trusted courts more. Meanwhile, the percentage of adults who said they reported for jury service in the previous five years fell from an average of nine percent before 2020 to just four percent in 2025.

Annenberg Public Policy Center of the University of Pennsylvania

Tortoises

Florida has been developing many regions that were previously the habitat for the gopher tortoise, a native species that has been considered for placement on the Endangered Species List given the habitat loss due to new construction. There has been a relocation program in place since 2009 that requires developers to hire authorized individuals to relocate gopher tortoises on land slated for development. From 2009 to 2023, over 97,000 tortoises have been moved around the state, enough to make the gopher tortoise the most-relocated animal in the Southeast and leading some scientists to conclude that about a third of the entire gopher tortoise population of the state of Florida has been relocated at some point in the past 15 years.

Stephanie Castellano, bioGraphic

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