A 2022 California law mandates net-zero greenhouse gas emissions by 2045 and negative emissions every year thereafter. The state can achieve this but will have to act quickly and thoroughly, and success will require new technologies for sectors difficult to decarbonize, a new Stanford University study finds. The state will need to decarbonize not only cars and electricity but also trucks, trains, planes, agriculture, and factories, while slashing pollution from its oil refineries.

The research team created a new model that projects emissions, society-wide economic costs, and consumption of energy resources under many scenarios for California to reach net-zero emissions by 2045. The model uses data from U.S. federal agencies, national laboratories, California state agencies, past studies, and various other online public sources. (Data sources are provided in the study’s Appendix B.) The model forecasts that 170 gigawatts of new generation and 54 gigawatts of storage will be needed by 2045, compared with California’s current generation capacity of 80 GW, as transportation, buildings, and industry transition from fossil fuels to low-carbon sources of electricity. The expansion of electricity will be needed despite expected gains in energy efficiency in many technologies.

The study, published this week in the journal Energy Policy, provides a detailed roadmap for meeting California’s net-zero mandate. First, commercially available technologies can slash the state’s emissions in half. Technologies proven at pilot scale that need commercial development and lower costs could address another 25%. The final quarter will rely on inventions still being worked on in laboratories.

“One key to success will be building an emission-free power grid using a combination of solar, wind, batteries, and sources of clean, firm power like natural gas with carbon capture and storage or nuclear power,” said the study’s senior author, Sally Benson, the Precourt Family Professor of energy science and engineering in the Stanford Doerr School of Sustainability.

The study, which was funded by several industry associations and trade unions impacted by the state’s move to net-zero emissions, also examines some policy and economic implications for the state.

“We will need to build this infrastructure at an unprecedented pace to put proven technologies to work at the scale we need,” added Benson, who was the chief strategist for the energy transition at the White House Office of Science & Technology Policy from 2021 to 2023.

First 52%: Commercial technologies

The necessary technologies already in commercial use that could halve California emissions include renewable electricity generation, batteries for storing that energy, electric passenger vehicles, heat pumps, and machines that produce methane fuel from wastewater, manure, and food and plant waste.

However, significant administrative and logistical barriers could stymie deployment of these technologies at the required speed and scale. The state is already experiencing overwhelmingly long queues to connect new renewable energy generation and grid-scale energy storage to the grid. Local ordinances frequently block permits for new power plants. Other obstacles include the early termination of federal tax credits for EVs and home solar, federal challenges to California banning sales of gas-powered cars in 10 years, elevated financing costs, and supply chain disruptions.

“California can build the infrastructure it needs to meet the 2045 mandate, but the state must implement policies to overcome regulatory and logistical barriers,” said the study’s lead author, Joshua Neutel, a Ph.D. student in civil and environmental engineering, a joint department of Stanford’s School of Engineering and Doerr School of Sustainability.

Several readily available measures save more money than they cost to implement, after accounting for state and federal incentives—many of which are slated to end in the coming months. The authors estimate electric passenger vehicles, solar and wind power, reduced in-state oil production, and replacement of fossil-based gas with methane fuel made through anaerobic digestion could eliminate 44% of the state’s greenhouse gas emissions (based on estimated 2045 emissions if the state were to continue business as usual).

Next 25%: Early-stage technologies

The authors estimate a quarter of emissions abatement could come from technologies in the early stages of commercialization, including zero-emission heavy-duty vehicles, clean industrial heating from electricity and hydrogen, and carbon capture and sequestration (CCS).

Eliminating carbon emissions from heavy-duty vehicles could reduce California emissions 12%. However, emission-free trucks still need to improve their range and cargo capacity while reducing charging time and purchase price. Another area in early-stage deployment involves switching several industries from fossil fuels to carbon-free electricity and green hydrogen. This accounts for 5% of emission reductions in the authors’ projections.

CCS entails capturing carbon dioxide directly at the source, such as at gas-fired power plants and factories, and securely sequestering the emissions deep underground. In some hard-to-decarbonize sectors, like oil refining and producing cement, hydrogen, and some electricity, CCS may be the most viable option in the near and medium term, according to the authors. The study confirms prior findings that a limited amount of natural gas power paired with CCS (34 of 170 gigawatts, or about 20% of new generation capacity) could vastly reduce the number and costs of wind and solar farms. Pairing bioenergy with CCS could remove another 2% of emissions from 2019 levels to reach net-zero emissions.

Final 23%: Research-phase technologies

Nascent technologies still in the research phase include decarbonized trains, planes, and boats; low-emission refrigerants; and carbon dioxide removal (CDR) from the atmosphere. Replacing fossil fuels for planes, trains, and boats with electricity, hydrogen, and renewable fuels faces challenges from their weight, cargo capacity, costs, and the limited availability of clean fuels.

Traditional refrigerants are powerful greenhouse gases up to 2,000 times more potent than CO₂ during their first 100 years in the atmosphere. Climate-friendly alternatives, possibly including CO₂ as a refrigerant, are still in the early stages of development.

CDR will play a significant role, with the researchers’ model projecting that California will need to sequester about 45-75 million tons of CO₂ annually by 2045 through CDR, in line with the state’s 2022 forecast. Explored CDR options include bioenergy with CCS and direct air capture plants. The prior emits but then sequesters biogenic CO₂ through industrial processes like hydrogen and electricity generation. The latter extracts CO₂ directly from ambient air and stores it underground.

“If net-zero by 2045 is a binding constraint, then large amounts of CDR will be needed,” said study co-author Sarah Saltzer, managing director of the Stanford Center for Carbon Storage. Current methods for extracting carbon dioxide from ambient air remain costly and energy intensive.

Political and economic implications

The study recommends several policy changes, including streamlining the permitting of, and grid connections for, new generation, energy storage, and power lines. This year, the state has taken initial steps to do this.

The research advises that California should consider incentives for adding CCS to existing natural gas-fired power plants. For example, it could qualify such power plants as one way for utilities to meet the state’s renewable portfolio standard. This could prevent expensive overbuilding of solar power plus batteries.

This work also supports maintenance of the state’s EV sales mandate for 100% clean vehicles by 2035 and consideration of similar policies for building appliances. Policymakers could develop roadmaps for advancing “renewable natural gas” and “renewable diesel,” which are chemically equivalent to fossil-based natural gas and diesel but made from biological feedstocks, said the researchers. These fuels have a limited global supply but could be vital for decarbonizing hard-to-abate sectors.

“Reaching net-zero by 2045 is not so much a challenge in cost,” said Benson, “but a challenge in getting the necessary technologies available in time and establishing the social, political, and economic environment to deploy these technologies rapidly and broadly.”

Other Screen Protectors I’ve Tested

ESR Armorite Screen Protector and Privacy Protector for $20: This pack is better value than Smartish’s screen protectors, because you get three tempered glass sheets instead of two. All the necessary equipment is here, from an application tool to wet wipes. While it uses a pull-tab, I found Smartish’s and Dbrand’s systems easier to use overall. I also tried ESR’s Privacy Protector, which was effective at blocking the screen when viewed from the left or right. I didn’t see a major impact on sharpness or color accuracy. I tested ESR’s Armorite Pro ($36) with tempered glass made by Corning, the company that makes most of the glass found on smartphones. The edge feels a tiny bit sharp, but it was otherwise easy to apply and looks great.

OtterBox Glass Screen Protector for $40: OtterBox is now using a pull-tab system for installation, and the process was very easy, though I did end up with more air bubbles than my top picks. It comes with a microfiber, wet wipe, and dust-removal stickers, but you only get one aluminosilicate screen protector.

Nomad ProShield Glass for $39: Here’s another aluminosilicate screen protector made by Corning, the company that makes the glass on most smartphones. Instead of a pull-tab, you put the phone in the application tool, then close the tool like a book and push down as glass sticks to glass. It worked surprisingly well, with just a few air bubbles. I still feel like the edges of the protector are a little sharper than I’d like, compared to the Dbrand and Smartish. It also only comes with one.

Zagg XTR5 Screen Protector for $60: Zagg is really going after the blue-light crowd. If you think cutting as much blue light from your smartphone will help you sleep better or might be easier on the eyes, by all means, try the XTR5. It may give you peace of mind. But studies are still mixed on the efficacy of this, though Zagg claims this version specifically cuts out the wavelengths that impact sleep and eye comfort. The glass feels smooth and is thick. It annoyingly doesn’t cover the entire screen, but the edges don’t feel sharp. Installation was easy with the pull-tab system (a first for Zagg), and the company says this tempered glass is fortified with graphene for extra durability; it’s hard to say just how much it helps. It’s worth noting that I did notice an impact on color accuracy. Compared with another iPhone, the XTR5 delivered a cooler tone to the iPhone screen.

Astropad Fresh Coat Anti-Reflective Screen Protector for $35: Apple already added an anti-reflective coating to all of the new iPhones, but this Astropad screen protector can take that even further. Installation was easy with the pull-tab application system, though I got far more air bubbles with it than with any of the other pull-tab installations. It actually does work and cuts glare. I compared it with another iPhone that didn’t have a screen protector, and noticed glare was less pronounced with the Astropad. There’s no real loss in color accuracy or sharpness. I compared photos on the two phones, and they looked virtually identical. I haven’t found much reason to complain about glare on the iPhone 17 screen, but if something like that has bothered you before, the Fresh Coat might be up your alley.

Rhinoshield Impact Protector Pro (Transparent) for $36: This flexible screen protector was easy to apply, though I am a bit miffed that Rhinoshield didn’t include a wet wipe (just a microfiber and dust-removal stickers). It still left air bubbles, but the squeegee was able to get rid of them. The edges are a little sharp, which isn’t a problem on my top picks. This isn’t as much of an issue when paired with a case. The company claims it restricts blue light, but take this with a grain of salt. Studies have shown mixed results that cutting blue light from a smartphone will help you sleep better.

UAG Glass Shield Screen Protector for $40: This tempered glass screen protector is available for the iPhone 17, iPhone Air, iPhone 17 Pro, and iPhone 17 Pro Max. But the application tool is a little too basic. It allows for some room for error, at least, more than my top picks, and it also gave me a lot of air bubbles. The glass is pretty thick, which feels protective, but you can also feel the sharp edges running along the side.

Other Great Cases

I’ve tested more than 50 cases for the iPhone 17 lineup. Not all of them deserve a top spot above, but many are still great and come in fun designs and styles. Check ’em out.

Alto Wood Case.

Photograph: Julian Chokkattu

Alto Wood Case for $41: I love a good wood case, but I have some mixed feelings about these cases from Alto. You can get custom laser-carved prints, like from its Wildlife or Flora series; you can even add your own image. But these look a little tacky to me. Why hide that gorgeous wood? You can choose from a range of wood styles, from olive wood to cherry. I’d probably grab something from the company’s Burl & Exotic Series. The case itself is OK. The rubber bumper around the edges is grippy, but feels a little cheap. The power button is solid, and there’s a cutout for the Camera Control button, but the volume rocker feels a tiny bit mushy.

Beats Rugged Case for $79: This case is the opposite of the Beats Kickstand case that I listed in the avoid section below. Where that case was super slippery, this one offers a much better grip. The buttons are clicky, the display and cameras are protected, and it looks very pretty. It’s not the grippiest case I’ve tried, nor is it the most rugged, despite its name. I prefer the Camera Control button design on the Nomad Rugged Case, which has a thicker bumper. It’s available for the iPhone 17, iPhone 17 Pro, and iPhone 17 Pro Max.

BodyGuardz Performance Pro and Pulse Cases for $50+: BodyGuardz’s Pulse case is a fine case that comes in a fun matcha color and includes a wrist strap. The Camera Control button is nicely elevated. Look along the side edges and you’ll see vents—this is to help disperse heat, along with the help of cooling gel on the inner lining. I’ve tried testing this in the past and haven’t noticed much of a difference in gaming performance on the phone. The directional speaker is something that does actually work. Basically, the case directs the audio from the rear speakers towards you instead of downward, and you can marginally hear the difference. The Performance Pro takes it to the max with larger vents, and it adds a kickstand. I just don’t like how the case feels when you hold it.

Burton Goods Heritage Leather Case.

Photograph: Julian Chokkattu

Burton Goods Heritage Leather Case for $79+: Burton Goods is from the creator of Pad & Quill, which shut down in 2023 due to bankruptcy. The company was known for its classy leather cases, and that has continued with the new brand. The Heritage will make you feel like you’re sitting on a cozy armchair near a fireplace in an old English study. The full-grain leather feels supple (and smells great), and the stitching gives it even more character. There’s MagSafe baked in, a microfiber interior, and all the buttons are responsive. The edges are raised well around the display and Camera Plateau, too. You can pair it with the Heritage MagSafe Wallet Stand, which is a magnetic wallet with a kickstand. I was able to fit about three credit cards, though the top cover flap makes it a little hard to remove the cards.

Rhinoshield SolidX and Clear Cases for $38+: I have no qualms with either of these Rhinoshield cases. The SolidX is robust, thick, and protective, with clicky buttons and MagSafe. The Clear case has extremely clicky buttons that stick out quite a bit, and it feels very sturdy. There’s just not much else to them, other than the fact that the company uses a proprietary material called Mono. It’s 100 percent recycled and is essentially a single compound, making recyclability easier.

OtterBox Symmetry Series cases.

Photograph: Julian Chokkattu

OtterBox Symmetry Series Case for $60: OtterBox’s Symmetry series is its most fun lineup because there are usually several nifty designs to choose from. Case in point, look at this adorable cactus embroidered case! It’s a fun texture to have on the back of your phone, and it’s super cute. This version is actually made from cactus leather, but other Symmetry cases are standard plastic. I don’t think the basic Symmetry cases are worth the $60 price, but the embroidered versions are worth considering. While these have MagSafe baked in, the embroidery does weaken the magnetic connection. It still charged my iPhone, but I wouldn’t trust it on a MagSafe car dock.

OtterBox Commuter Series Case for $50: OtterBox’s Commuter case is simple and inoffensive. You have a few muted colors to choose from, and the dual-layer design has a rubber slipcover surrounded by a harder plastic shell. I like the rubber edges as they help with grip, too. It checks off all the boxes—even the USB-C port is covered up—but it’s just not very exciting.

OtterBox Sole Series Case.

Photograph: Julian Chokkattu

OtterBox Sole Series Case for $70: I actually really like the look and feel of this case. The ridged edges are grippy, and the netting-like fabric texture on the back is so satisfying to run my fingers over. It’s kind of like sandpaper, but in a good way. The cameras and display are protected, and the buttons are clicky. However, I’m very confused by the included lanyard loop. It’s way too tiny to put on even the smallest wrists. I suspect you’re meant to affix it to a carabiner or backpack instead. If that’s your jam, you’ll like this. If not, the lanyard is removable, and you can buy another one designed for wrists.

Mous Super Thin Aramid Fibre Case for $70: Several companies now make aramid fiber ultra-thin cases, and honestly, you can’t go wrong with most of them. I prefer the subtle texture of Pitaka’s case (see above), but Mous’ Super Thin is a close second, and it even comes in a clear option with MagSafe. I very much like the raised protection for the camera, though the Camera Control button is exposed, and there’s less protection on the top and bottom, unlike Pitaka’s case. As always, this sturdy case is extremely thin and is not going to provide the best protection, especially for the screen, but it’ll cover the usual wear and tear. Pair it with a screen protector.

Thinborne Super Thin Aramid Fiber Case for $70: It’s super thin like the Pitaka and Mous aramid fiber cases, with baked-in MagSafe, but I like Pitaka’s designs better. All of the buttons are exposed here, including the Camera Control. Thinborne includes a screen protector, but you have to freehand the installation as it doesn’t come with an application tool.

Zagg Milan Snap case.

Photograph: Julian Chokkattu

Zagg iPhone 17 Cases for $50+: I have tried all of Zagg’s cases, and they’re all solid, though I prefer the Sedona (see above) the most. Here are some thoughts on the lineup. The Crystal Palace Snap With Stand has the same great kickstand as the Sedona, as well as an actual button for Camera Control, but this case is clear. It’s a great way to show off your iPhone’s color, though it smudges easily. The Manhattan Snap ditches the kickstand and is silicone, but I found it attracts too much dust and lint; it is very soft, though. The Milan Snap has a fun iridescent color, and the Santa Cruz Snap With Stand has a striking, colorful bumper that’s grippy, but the Camera Control button is a cutout. The Luxe Snap might be my favorite of the lot in terms of design, with a fun texture on the back and grooved edges, but there’s no kickstand. Finally, the Rainier Case With Kickstand is the newest in Zagg’s lineup, and if you want robust protection, this one will satisfy. It’s a two-shell case with a hard and thick bumper, and seriously raised edges for maximum screen protection with extra-thick corners. Even the USB-C port is covered up. You get the same great kickstand, but the buttons are a bit mushy.

ESR Clear, Soft, and Tough Magnetic Case for $30: ESR has three versions of this case, each in a different material. The Soft employs a soft-touch silicone, and it’s quite nice, with clicky buttons and a dedicated Camera Control button. The Clear is, well, clear, and the Tough uses a hard plastic shell. None of them particularly excites me, but what makes them unique is the built-in kickstand that surrounds the camera module. It’s a neat idea, but you can only prop these phones up in landscape orientation. Technically, you can put them upright in portrait mode, but the phone has to be upside down. Either way, the Zagg recommendation above is a much better kickstand case.

Smartish cases.

Photograph: Julian Chokkattu

Smartish Gripzilla, Gripmunk, and Wallet Slayer Vol. 2 Cases for $20+: These cases are nice and affordable. The Gripzilla has textured edges that make for a nice grip, though it’s nowhere near as grippy as Dbrand’s Grip case that I recommend above. The Gripmunk has some ridges to help with grip, and the Wallet Slayer Vol. 2 lets you stuff several credit cards on the back. However, the wallet interferes with MagSafe and has no magnets inside, so it cuts you off from wireless charging. It also makes the case very thick. They’re all solid cases for the money, and you should shop directly from Smartish as it has some exclusive designs on its store.

Matter HT Snap Cases for $60: Formerly known as Atom Studios, these “Snap” cases aren’t actually cases. They’re just a backing you can magnetically stick to your phone to protect the rear glass. The company offers them in a clear, wood fiber, or agave material. They all look nice and feel great, especially the Clear version for the iPhone Air. However, I don’t see the point of these. They don’t cover the edges at all, which is where you’ll most likely see scuffs and scratches after a drop. I’d much rather go for an ultra-thin case that wraps the edges of a phone, or something like the Arc Pulse.

UAG Pathfinder.

Photograph: Julian Chokkattu

UAG Cases for $45+: I have tested the full suite of UAG’s cases, from the Plyo and the Monarch Pro to the Metropolis LT and Plasma XTE. If I had to pick one, I’d buy the Pathfinder ($60). I love the bright yellow color, and the design is bold, but it works. It makes me feel tactical, like I’m about to scale and infiltrate a building. The problem with all of UAG’s cases is that they’re expensive, and none of them feature a dedicated button for Camera Control; it’s all a cutout. (I’ve just come to really prefer having an actual button on the case!) I also like the UAG Dot ($45) and its fun translucent case.

Avoid These Cases

Beats Kickstand Case for $59: This case is available for the iPhone 17, iPhone 17 Pro, and iPhone 17 Pro Max, but not the iPhone Air. I feel bad not recommending it because it’s adorable, especially in pink, and the kickstand is super creative. Instead of embedding a kickstand into the case, the included lanyard has a pill-shaped kickstand that pops out. Place it on one of the longer edges of the iPhone, and voila, kickstand! The problem is that it doesn’t work at all in portrait orientation, so it’s limited as a kickstand case. Also, the polycarbonate case is shockingly slippery. I don’t think I’ve ever used a case more slippery. I was so surprised I showed my wife, and she immediately said, “Yeah, no, I don’t like that.” I guess that’s why a lanyard is included.

Mujjo Full Leather Wallet Case for $69: I like Mujjo’s leather cases, but I don’t really like the ones with a wallet sleeve embedded into the case itself. Firstly, the sleeve barely fits my card properly, let alone three, like the company claims. It’s also really hard to take the cards out. While Mujjo has built-in magnets in the case, the magnetic connection is fairly weak because the sleeve interrupts it. Not to mention the fact that you have to remove your cards to actually use MagSafe. It just seems counterintuitive. Just get a MagSafe wallet at that point.

OtterBox Defender Series Pro XT Case for $80: I’m so used to OtterBox’s Defender series having solid colors that the clear design here threw me off. I don’t hate it, but it does show smudges easily. While I usually choose this case as the most protective due to its dual-layer design (a polycarbonate frame sits on top and a rubber slipcover rests underneath), I ran into a problem. The Camera Control button is way too responsive. It’s so easy to press that I kept launching the camera every time I picked up the iPhone. My grip alone would end up pushing the button. I have tried installing and reinstalling this case several times to make sure the fit was right, but the problem still keeps happening. Bah.

Smartish Wallet Slayer Vol. 1 for $30: This is an odd case. The wallet sleeve on the back is really tight, and I had trouble stuffing two cards in. Taking them out isn’t easy either because they get stuck on the edge. Smartish also advertises a kickstand, but there is no kickstand on the case. Instead, you’re supposed to use your own credit card as the kickstand, which is just a little weird.

UAG Trooper Case for $65: Cases are so good these days, which is why it irks me when there’s an obvious flaw in a design. UAG’s Trooper is a rugged, tough case that is very bulky. Yet instead of adding a button for Camera Control, the company kept a cutout. But when the edge is so thick, it’s genuinely hard to press this button, even if the back edge is sloped in. (Could be my fat fingers.) The volume rocker and Action Button are also hard to press.

The Protein Plus options are pretty broad, comprising about half of Factor’s menu items overall. The meals remain mostly stolidly middle American: garlic herb chicken, barbecue wings, a red pepper frittata for breakfast. Jamaican jerk salmon and a Thai yellow curry chicken were among the most peripatetic options I tried, but even these feel domesticated, accessibly tame. (I did in fact like the jerk salmon a lot more than I expected to.)

Most dishes, though, are classic square meals: a meat, a starch, a veggie that’s probably green. It’s almost wholesome, Midwestern mom food. Heck, Factor—founded and based in Illinois—even has a Midwesterner’s sense of improvised adventure: An “unstuffed pepper” is basically the rice and meat and tomato sauce you’d canonically stuff into a bell pepper, but delivered in saucy meatball form with bell pepper bits strewn amid the rice. It looked sloppy, and it tasted like pure distilled comfort. If you hate what’s essentially a peppery meatball stew, I don’t know you.

In bygone years, Factor was perhaps over-reliant on mashes and hashes to fill out meals, but these made only a few appearances—including an actually kinda tasty mashed potatoes with leeks, served as a gloppy side to a pleasantly thick slab of filet mignon that arrived medium-rare, and reheated up to more like medium.

The proteins, uniformly, came out tender and relatively juicy, whether chicken or shrimp or beef. Reheated veggies are always difficult to manage in terms of texture, and that was true here, too. In general, Factor’s veggies were likely to be a little soggy if you nuked them—and a lot better if you put them in an air fryer or convection oven. Also, steer toward meals with brown and wild rice over white or “risotto.”

Over the Long Haul

Photograph: Matthew Korfhage

I will always like fresh-cooked food better than meals that have been prepared and reheated from a box: The brightness of a fresh tomato, the pop of a pea, the lively crispness of a just-so carrot, are impossible to replicate in food made yesterday or last week. But proteins and stews fared pretty well in particular, and so the Protein Plus options amounted to my best experience with Factor. It was also among my favorite prepared meal services overall. (See also WIRED’s guide to the best delivery meal kits.)