Rhode Island issues its plan to achieve 100% renewable electricity by 2030

EPA Auto Emissions Proposal 2027-2032 sets strict tailpipe emissions limits, accelerating electric vehicle adoption, cutting greenhouse gases, advancing climate policy, and reducing oil dependence through battery-electric cars and trucks across U.S. markets.

Key Points

An EPA plan setting strict tailpipe limits to drive EV adoption, cut greenhouse gases, and reduce oil use in vehicles.

✅ Cuts GHGs 56% vs. 2026 standards; improves national air quality.

✅ Targets up to two-thirds EV sales by 2032 nationwide.

✅ Reduces oil imports by about 20 billion barrels; lowers costs.

The Biden administration is proposing strict new automobile pollution limits that would require up to two-thirds of new vehicles sold in the U.S. to be electric by 2032, a nearly tenfold increase over current electric vehicle sales.

The proposed regulation, announced Wednesday by the Environmental Protection Agency, would set tailpipe emissions limits for the 2027 through 2032 model years that are the strictest ever imposed — and call for far more new EV sales than the auto industry agreed to less than two years ago, a shift aligned with U.S. EV sales momentum in early 2024.

If finalized next year as expected, the plan would represent the strongest push yet toward a once almost unthinkable shift from gasoline-powered cars and trucks to battery-powered vehicles, as the market approaches an inflection point in adoption.

The Biden administration is proposing strict new automobile pollution limits that would require up to two-thirds of new vehicles sold in the U.S. to be electric by 2032, a nearly tenfold increase over current electric vehicle sales.

The proposed regulation, announced Wednesday by the Environmental Protection Agency, would set tailpipe emissions limits for the 2027 through 2032 model years that are the strictest ever imposed — and call for far more new EV sales than the auto industry agreed to less than two years ago, a direction mirrored by Canada's EV sales regulations now being finalized.

If finalized next year as expected, the plan would represent the strongest push yet toward a once almost unthinkable shift from gasoline-powered cars and trucks to battery-powered vehicles, with many analysts forecasting widespread adoption within a decade among buyers.

Reaching half was always a “stretch goal," given that EVs still trail gas cars in market share and contingent on manufacturing incentives and tax credits to make EVs more affordable, he wrote.

“The question isn’t can this be done, it’s how fast can it be done,” Bozzella wrote. “How fast will depend almost exclusively on having the right policies and market conditions in place.”

European car maker Stellantis said that, amid broader EV mandate debates across North America, officials were “surprised that none of the alternatives” proposed by EPA "align with the president’s previously announced target of 50% EVs by 2030.''

Q. How will the proposal benefit the environment?

A. The proposed standards for light-duty cars and trucks are projected to result in a 56% reduction in projected greenhouse gas emissions compared with existing standards for model year 2026, the EPA said. The proposals would improve air quality for communities across the nation, and, with actual benefits influenced by grid mix — for example, Canada's fossil electricity share affects lifecycle emissions — avoiding nearly 10 billion tons of carbon dioxide emissions by 2055, more than twice the total U.S. CO2 emissions last year, the EPA said.

The plan also would save thousands of dollars over the lives of the vehicles sold and reduce U.S. reliance on approximately 20 billion barrels of oil imports, the agency said.

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U.S. Clean Hydrogen Hubs aim to scale production, storage, transport, and use as DOE and the Biden administration fund regional projects under the infrastructure law, blending green and blue hydrogen, carbon capture, renewables, and pipelines.

Key Points

Federally funded regional projects to make, move, and use low-carbon hydrogen via green, blue, and pink routes.

✅ $7B DOE funding via infrastructure law

✅ Mix of green, blue, pink hydrogen pathways

✅ Targets 10M metric tons annually by 2030

New details are emerging about the Biden administration’s landmark plans to build out a U.S. clean hydrogen industry.

On Friday, the Department of Energy named the seven winners of $7 billion in federal funds to establish regional hydrogen hubs. The hubs — funded through the infrastructure law — are part of the administration’s efforts to jump-start an industry it sees as key to achieving climate goals like the goal of 100 percent clean electricity by 2035 set by the administration. The aim is to demonstrate everything from the production and storage of hydrogen to its transport and consumption.

“All across the country, from coast to coast, in the heartland, we’re building a clean energy future here in America, not somewhere else,” President Joe Biden said while announcing the hubs in Philadelphia.

From 79 initial proposals, DOE chose the following: the Mid-Atlantic Hydrogen Hub, Appalachian Hydrogen Hub, California Hydrogen Hub, Gulf Coast Hydrogen Hub, Heartland Hydrogen Hub, Midwest Hydrogen Hub and Pacific Northwest Hydrogen Hub.

Many of the winning proposals are backed by state government leaders and industry partners, and by Southeast cities that have ramped up clean energy purchases in recent years as well. The Midwest hub, for example, is a coalition of Illinois, Indiana and Michigan — supported by politicians like Illinois Gov. J.B. Pritzker (D), as well as such companies as Air Liquide, Ameren Illinois and Atlas Agro. The mid-Atlantic hub is supported by Democratic members of Congress representing the region, including Delaware Sens. Chris Coons and Tom Carper and Rep. Lisa Blunt Rochester.

The administration hopes the hubs will produce 10 million metric tons of “clean” hydrogen annually by 2030. But much about the projects remains unknown — including how trends like cheap batteries for solar could affect clean power supply — and dependent on negotiations with DOE.

A win for ‘blue’ hydrogen?
Nearly all hydrogen created in the U.S. today is extracted from natural gas through steam methane reformation. The emissions-intensive process produces what is known as “grey” hydrogen — or “blue” hydrogen when combined with carbon capture and storage.

Four recipients — the Appalachian, Gulf Coast, Heartland and Midwest hydrogen hubs — include blue hydrogen in their plans, though the infrastructure law only mandated one.

That has drawn the ire of environmentalists, who argue blue hydrogen is not emissions-free, partly because of the potential for methane leaks during the production process.

“This is worse than expected,” Clean Energy Group President Seth Mullendore said after the recipients were announced Friday. “The fact that more than half the hubs will be using fossil gas is outrageous.”

Critics have also pointed out that many of the industry partners backing the hub projects include oil and gas companies. The coalitions are a mix of private-sector groups — often including renewable energy developers — and government stakeholders. Proposals have also looped in universities, utilities, environmental groups, community organizations, labor unions and tribal nations, among others.

“The massive build out of hydrogen infrastructure is little more than an industry ploy to rebrand fracked gas,” said Food & Water Watch Policy Director Jim Walsh in a statement Friday. “In a moment when every political decision that we make must reject fossil expansion, the Biden administration is going in the opposite direction.”

The White House has emphasized that roughly two-thirds of the $7 billion pot is “associated” with the production of “green” hydrogen, which uses electricity from renewable sources. Two of the chosen proposals — in California and the Pacific Northwest — are making green hydrogen their focus, reflecting advances such as offshore green hydrogen being pursued by industry leaders, while three other hubs plan to include green hydrogen alongside hydrogen made with natural gas (blue) or nuclear energy (pink).

Many hubs plan to use several methods for hydrogen production, and globally, projects like Brazil's green hydrogen plant highlight the scale of investment, but the exact mix may change depending on which projects make it through the DOE negotiations process. The Midwest hub, for example, told E&E News it’s pursuing an “all-of-the-above” strategy and has projects for green, blue and “pink” hydrogen. The mid-Atlantic hub in southeastern Pennsylvania, Delaware and New Jersey will also generate hydrogen with nuclear reactors.

Energy Secretary Jennifer Granholm has described clean hydrogen as a fresh business opportunity, especially for the natural gas industry, which has supported the concept of sending hydrogen to market through its pipeline network. Lawmakers like Sen. Joe Manchin (D-W.Va.) — who said the Appalachian hub will make West Virginia the “new epicenter of hydrogen” — have pushed for continuing to use natural gas to make hydrogen in his state.

“Natural gas utilities are committed to exploring all options for emissions reduction as demonstrated by the 39 hydrogen pilot projects already underway and are eager to participate in a number of the hubs,” said American Gas Association President and CEO Karen Harbert in a statement Friday.

Green hydrogen also has faced criticism. Some groups argue that the renewable resources needed to produce green hydrogen are limited, even with sources such as wind, solar and hydropower technology, so funding should be reserved for applications that cannot be easily electrified, mostly industrial processes. There also is uncertainty about how the Treasury Department will handle hydrogen made from grid electricity — which can include power from fossil fuel plants — in its upcoming guidance on the first-ever tax credit for clean hydrogen production.

“Even the cleanest forms of hydrogen present serious problems,” Walsh said. “As groundwater sources are drying up across the country, there is no reason to waste precious drinking water resources on hydrogen when there are cheaper, cleaner energy sources that can facilitate a real transition off fossil fuels.”

But Angelina Galiteva, CEO of the hub in drought-prone California, said hydrogen will enable the state “to increase renewable penetration to reach all corners of the economy,” noting parallel initiatives such as Dubai's solar hydrogen plans that illustrate the potential.

“Transitioning to renewable clean hydrogen will pose significantly less stress on water resources than remaining on the current fossil path,” she said.

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UK Renewable Energy Milestones: wind outpacing gas, record solar output, offshore wind growth, National Grid data, and a net-zero grid by 2035, despite planning reforms, connection queues, and grid capacity constraints.

Key Points

Key UK advances where wind beat gas, solar set records, and policies target a 2035 net-zero electricity grid.

✅ Wind generated one-third of electricity, outpacing gas

✅ Record solar output reported by National Grid in April

✅ Onshore wind easing via planning reforms; grid delays persist

In the first three months of this year a third of the country's electricity came from wind farms, with the UK leading the G20 for wind power according to research from Imperial College London has shown.

National Grid has also confirmed that April saw a record period of solar energy generation, and wind generation set new records earlier in the year.

By 2035 the UK aims for all of its electricity to have net zero emissions, though progress stalled in 2019 in some areas.

"There are still many hurdles to reaching a completely fossil fuel-free grid, but wind out-supplying gas for the first time, a sign of wind leading the power mix, is a genuine milestone event," said Iain Staffell, energy researcher at Imperial College and lead author of the report.

The research was commissioned by Drax Electrical Insights, which is funded by Drax energy company.

The majority of the UK's wind power has come from offshore wind farms, and wind generated more electricity than coal in 2016 marking an early shift. Installing new onshore wind turbines has effectively been banned since 2015 in England.

Under current planning rules, companies can only apply to build onshore wind turbines on land specifically identified for development in the land-use plans drawn up by local councils. Prime Minister Rishi Sunak agreed in December to relax these planning restrictions to speed up development.

Scientists say switching to renewable power is crucial to curb the impacts of climate change, with milestones like wind and solar topping nuclear underscoring the shift, which are already being felt, including in the UK, which last year recorded its hottest year since records began.

Solar and wind have seen significant growth in the UK. In the first quarter of 2023, 42% of the UK's electricity came from renewable energy, with 33% coming from fossil fuels like gas and record-low coal shares.

Some new solar and wind sites are waiting up to 10 to 15 years to be connected because of a lack of capacity in the electricity system.

And electricity only accounts for 18% of the UK's total power needs. There are many demands for energy which electricity is not meeting, such as heating our homes, manufacturing and transport.

Currently the majority of UK homes use gas for their heating - the government is seeking to move households away from gas boilers and on to heat pumps which use electricity.

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California EV mandate will phase out new gas cars, raising power demand and requiring renewable energy, grid upgrades, fast chargers, time-of-use rates, and vehicle-to-grid to stabilize loads and reduce emissions statewide.

Key Points

California's order ends new gas-car sales by 2035, driving grid upgrades, charging infrastructure, and cleaner transport.

✅ 25% higher power demand requires new generation and storage

✅ Time-of-use pricing and midday charging reduce grid stress

✅ Vehicle-to-grid and falling battery costs enable reliability

Leaning on the hood of a shiny red electric Ford Mustang, California Gov. Gavin Newsom signed an executive order Wednesday to end the sale of new gas-burning cars in his state in 15 years, a move with looming challenges for regulators and industry.

Now comes the hard part.

Energy consultants and academics say converting all passenger cars and trucks to run on electricity in California could raise power demand by as much as 25%. That poses a major challenge to state power grids as California is already facing periodic rolling blackouts as it rapidly transitions to renewable energy.

California will need to boost power generation, scale up its network of fast charging stations, enhance its electric grid to handle the added load and hope that battery technology continues to improve enough that millions in America’s most populous state can handle long freeway commutes to schools and offices without problems.

“We’ve got 15 years to do the work,” said Pedro Pizarro, chief executive of Edison International, owner of Southern California Edison, a utility serving 15 million people in the state. “Frankly the state agencies are going to have to do their part. We’ve got to get to the permitting processes, the approvals; all of that work is going to have to get accelerated to meet [Wednesday’s] target.”

Switching from petroleum fuels to electricity to phase out the internal combustion engine won’t happen all at once—Mr. Newsom’s order applies to sales of new vehicles, so older gas-powered cars will be on the road in California for many years to come. But the mandate means the state will face a growing demand for megawatts.

California is already facing a shortfall of power supplies over the next couple of years. The problem was highlighted last month when a heat wave blanketed the western U.S. and the state’s grid operator instituted rolling blackouts on two occasions.

“It is too early to tell what kind of impact the order will have on our power grid, and we don’t have any specific analysis or projections,” said Anne Gonzalez, a spokeswoman for the California Independent System Operator, which runs the grid.

Currently, California faces a crunchtime in the early evening as solar power falls off and demand to power air conditioners remains relatively high. Car charging presents a new potential issue: what happens if surging demand threatens to crash the grid during peak hours?

Caroline Winn, the chief executive of San Diego Gas & Electric, a utility owned by Sempra Energy that serves 3.6 million people, said there will need to be rules and rates that encourage people to charge their cars at certain times of the day, amid broader control over charging debates.

“We need to get the rules right and the markets right, informed by lessons from 2021, in order to resolve this issue because certainly California is moving that way,” she said.

The grid will need to be upgraded to prepare for millions of new electric vehicles. The majority of people who own them usually charge them at home, which would mean changes to substations and distribution circuits to accommodate multiple homes in a neighborhood drawing power to fill up batteries. The state’s three main investor-owned utilities are spending billions of dollars to harden the grid to prevent power equipment from sparking catastrophic wildfires.

“We have a hell of a lot of work to do nationally. California is ahead of everybody and they have a hell of a lot of work to do,” said Chris Nelder, who studies EV-grid integration at the Rocky Mountain Institute, an energy and environment-policy organization that promotes clean-energy solutions.

Mr. Nelder believes the investment will be worth it, because internal combustion engines generate so much waste heat and emissions of uncombusted hydrocarbons that escape out of tailpipes. Improving energy efficiency by upgrading the electrical system could result in lower bills for customers. “We will eliminate a vast amount of waste from the energy system and make it way more efficient,” he said.

Some see the growth of electric vehicles as an opportunity more than a challenge. In the afternoon, when electricity demand is high but the sun is setting and solar power drops off quickly, batteries in passenger cars, buses and other vehicles could release power back into the electric grid to help grid stability across the system, said Matt Petersen, chairman of the Transportation Electrification Partnership, a public-private effort in Los Angeles to accelerate the deployment of electric vehicles.

The idea is known as “vehicle-to-grid” and has been discussed in a number of countries expanding EV use, including the U.K. and Denmark.

“We end up with rolling batteries that can discharge power when needed,” Mr. Petersen said, adding, “The more electric vehicles we add to the grid, the more renewable energy we can add to the grid.”

One big hurdle for the widespread deployment of electric cars is driving down the cost of batteries to make the cars more affordable. This week, Tesla Inc. Chief Executive Elon Musk said he expected to have a $25,000 model ready by about 2023, signaling a broader EV boom in the U.S.

Shirley Meng, director of the Sustainable Power and Energy Center at the University of California, San Diego, said she believed batteries would continue to provide better performance at a lower cost.

“I am confident the battery technology is ready,” she said. Costs are expected to fall as new kinds of materials and metals can be used in the underlying battery chemistry, dropping prices. “Batteries are good now, and they will be better in the next 10 years.”

John Eichberger, executive director of the Fuels Institute, a nonprofit research group launched by the National Association of Convenience Stores, said he hoped that the California Air Resources Board, which is tasked with developing new rules to implement Mr. Newsom’s order, will slow the timeline if the market and electric build-out is running behind.

“We need to think about these critical infrastructure issues because transportation is not optional,” he said. “How do we develop a system that can guarantee consumers that they can get the energy when they need it?”

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Clean Energy Buyers Alliance 2030 Goal targets a 90% carbon-free U.S. grid, accelerating power-sector decarbonization via corporate renewable energy procurement, market and policy reforms, and customer demand to enable net-zero electrification across industries.

Key Points

The Alliance's plan to reach a 90% carbon-free U.S. electricity system by 2030 via customer-driven markets and policy.

✅ Corporate buyers scale renewable PPAs and aggregation

✅ Market and policy reforms unlock clean power access

✅ Goal aligns with net-zero and widespread electrification

The Clean Energy Buyers Association (CEBA) and the Clean Energy Buyers Institute (CEBI), which together make up the Clean Energy Buyers Alliance, have announced a profound new aspiration for impact: a 90% carbon-free U.S. electricity system by 2030 and a global community of energy customers driving the global energy transition forward.

Alongside the two organizations’ bold new vision of the future – customer-driven clean energy for all – the Alliance will super-charge the work of its predecessor organizations, the Renewable Energy Buyers Alliance (REBA) and the REBA Institute, which represent the most iconic global companies with more than $6 trillion dollars in annual revenues and 14 million employees.

“This is the decisive decade for climate action and especially for decarbonization of the power sector,” said Miranda Ballentine, CEO of CEBA and CEBI. “To achieve a net-zero economy worldwide by 2050, the United States must lead. And the power sector must accelerate toward a 2030 timeline as electrification of other industries will be driving up power use.”

In the U.S. alone, more than 60% of electricity is consumed by the commercial and industrial sectors. Institutional energy customers have accelerated the deployment of clean energy solutions over the last 10 years to achieve increasingly ambitious greenhouse gas reduction targets, even as a federal coal plan remains under debate, and further cement the critical role of customers in decarbonizing the energy system. The Clean Energy Buyers Association Deal Tracker shows that 7.9 GW of new corporate renewable energy project announcements in the first three quarters of this year are equivalent to 40% of all new carbon free energy capacity added in the U.S. so far in 2021.

“With our new vision of customer-driven clean energy for all, we are also unveiling new organization brands,” Ballentine continued. “I’m excited to announce that REBA will become CEBA—the Clean Energy Buyers Association—and will focus on activating our community of energy customers and partners to deploy market and policy solutions for a carbon-free energy system. The REBA Institute will become the Clean Energy Buyers Institute (CEBI) and will focus on solving the toughest market and policy barriers to achieving a carbon-free energy system in collaboration with policymakers, leading philanthropies, and energy market stakeholders. Together, CEBA and CEBI will make up the new Clean Energy Buyers Alliance.”

To decarbonize the U.S. electricity system 90% by 2030, a goal aligned with California's 100% carbon-free mandate efforts, and to activate a community of customers driving clean energy around the world, the Clean Energy Buyers Alliance will drive three critical transformations to:

Unlock markets so that energy customers can use their buying power and market-influence, building on a historic U.S. climate deal this year, to accelerate electricity decarbonization.

Catalyze communities of energy customers to actively choose clean energy through Mission Innovation collaborations and to do more together than they could on their own.

Decarbonize the grid for all, since not every energy customer can or will use their buying power to choose clean energy.

“The Clean Energy Buyers Alliance is setting the bar for what energy buyers, utilities and governments should and need to be doing to achieve a carbon-free energy future,” said Michael Terrell, CEBA board chair and Director of Energy at Google. “This ambitious approach is a critical step in tackling climate change. The time for meaningful climate action is now and we must collectively be bolder and more ambitious in our actions in both the public and private sectors – starting today.”

This new vision of customer-driven clean energy for all is an unprecedented opportunity for every member of the Clean Energy Buyers Alliance community – from energy customers to providers to manufacturers – to all parties up and down the energy supply chain to lead the evolution of a new energy economy, which will require incentives to double investment in clean energy to rise to $4 trillion by 2030.

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Electric Car Motors convert electricity to torque via rotor-stator magnetic fields, using AC/DC inverters, permanent magnets or induction designs; they power EV powertrains efficiently and enable regenerative braking for energy recovery and control.

Key Points

Electric car motors turn electrical energy into wheel torque using rotor-stator fields, inverters, and AC or DC control.

✅ AC induction, PMSM, BLDC, and reluctance architectures explained

✅ Inverters manage AC/DC, voltage, and motor speed via frequency

✅ Regenerative braking recovers energy and reduces wear

When was the last time you stopped to think about how electric cars actually work, especially if you're wondering whether to buy an electric car today? We superfans of the car biz have mostly developed a reasonable understanding of how combustion powertrains work. Most of us can visualize fuel and air entering a combustion chamber, exploding, pushing a piston down, and rotating a crankshaft that ultimately turns the wheels. We generally understand the differences between inline, flat, vee-shaped, and maybe even Wankel rotary combustion engines.

Mechanical engineering concepts such as these are comparatively easy to comprehend. But it's probably a fair bet to wager that only a minority of folks reading this can explain on a bar napkin exactly how invisible electrons turn a car's wheels or how a permanent-magnet motor differs from an AC induction one. Electrical engineering can seem like black magic and witchcraft to car nuts, so it's time to demystify this bold new world of electromobility, with the age of electric cars arriving ahead of schedule.

How Electric Cars Work: Motors
It has to do with magnetism and the natural interplay between electric fields and magnetic fields. When an electrical circuit closes allowing electrons to move along a wire, those moving electrons generate an electromagnetic field complete with a north and a south pole. When this happens in the presence of another magnetic field—either from a different batch of speeding electrons or from Wile E. Coyote's giant ACME horseshoe magnet, those opposite poles attract, and like poles repel each other.

Electric motors work by mounting one set of magnets or electromagnets to a shaft and another set to a housing surrounding that shaft. By periodically reversing the polarity (swapping the north and south poles) of one set of electromagnets, the motor leverages these attracting and repelling forces to rotate the shaft, thereby converting electricity into torque and ultimately turning the wheels, in a sector where the electric motor market is growing rapidly worldwide. Conversely—as in the case of regenerative braking—these magnetic/electromagnetic forces can transform motion back into electricity.

How Electric Cars Work: AC Or DC?
The electricity supplied to your home arrives as alternating current (AC), and bidirectional charging means EVs can power homes for days as needed, so-called because the north/south or plus/minus polarity of the power changes (alternates) 60 times per second. (That is, in the United States and other countries operating at 110 volts; countries with a 220-volt standard typically use 50-Hz AC.) Direct current (DC) is what goes into and comes out of the + and - poles of every battery. As noted above, motors require alternating current to spin. Without it, the electromagnetic force would simply lock their north and south poles together. It's the cycle of continually switching north and south that keeps a motor spinning.

Today's electric cars are designed to manage both AC and DC energy on board. The battery stores and dispenses DC current, but again, the motor needs AC. When recharging the battery, and with increasing grid coordination enabling flexibility, the energy comes into the onboard charger as AC current during Level 1 and Level 2 charging and as DC high-voltage current on Level 3 "fast chargers." Sophisticated power electronics (which we will not attempt to explain here) handle the multiple onboard AC/DC conversions while stepping the voltage up and down from 100 to 800 volts of charging power to battery/motor system voltages of 350-800 volts to the many vehicle lighting, infotainment, and chassis functions that require 12-48-volt DC electricity.

How Electric Cars Work: What Types Of Motors?
DC Motor (Brushed): Yes, we just said AC makes the motor go around, and these old-style motors that powered early EVs of the 1900s are no different. DC current from the battery is delivered to the rotor windings via spring-loaded "brushes" of carbon or lead that energize spinning contacts connected to wire windings. Every few degrees of rotation, the brushes energize a new set of contacts; this continually reverses the polarity of the electromagnet on the rotor as the motor shaft turns. (This ring of contacts is known as the commutator).

The housing surrounding the rotor's electromagnetic windings typically features permanent magnets. (A "series DC" or so-called "universal motor" may use an electromagnetic stator.) Advantages are low initial cost, high reliability, and ease of motor control. Varying the voltage regulates the motor's speed, while changing the current controls its torque. Disadvantages include a lower lifespan and the cost of maintaining the brushes and contacts. This motor is seldom used in transportation today, save for some Indian railway locomotives.

Brushless DC Motor (BLDC): The brushes and their maintenance are eliminated by moving the permanent magnets to the rotor, placing the electromagnets on the stator (housing), and using an external motor controller to alternately switch the various field windings from plus to minus, thereby generating the rotating magnetic field.

Advantages are a long lifespan, low maintenance, and high efficiency. Disadvantages are higher initial cost and more complicated motor speed controllers that typically require three Hall-effect sensors to get the stator-winding current phased correctly. That switching of the stator windings can result in "torque ripple"—periodic increases and decreases in the delivered torque. This type of motor is popular for smaller vehicles like electric bikes and scooters, and it's used in some ancillary automotive applications like electric power steering assist.

Permanent-Magnet Synchronous Motor (PMSM): Physically, the BLDC and PMSM motors look nearly identical. Both feature permanent magnets on the rotor and field windings in the stator. The key difference is that instead of using DC current and switching various windings on and off periodically to spin the permanent magnets, the PMSM functions on continuous sinusoidal AC current. This means it suffers no torque ripple and needs only one Hall-effect sensor to determine rotor speed and position, so it's more efficient and quieter.

The word "synchronous" indicates the rotor spins at the same speed as the magnetic field in the windings. Its big advantages are its power density and strong starting torque. A main disadvantage of any motor with spinning permanent magnets is that it creates "back electromotive force" (EMF) when not powered at speed, which causes drag and heat that can demagnetize the motor. This motor type also sees some duty in power steering and brake systems, but it has become the motor design of choice in most of today's battery electric and hybrid vehicles.

Note that most permanent-magnet motors of all kinds orient their north-south axis perpendicular to the output shaft. This generates "radial (magnetic) flux." A new class of "axial flux" motors orients the magnets' N-S axes parallel to the shaft, usually on pairs of discs sandwiching stationary stator windings in between. The compact, high-torque axial flux orientation of these so-called "pancake motors" can be applied to either BLDC or PMSM type motors.

AC Induction: For this motor, we toss out the permanent magnets on the rotor (and their increasingly scarce rare earth materials) and keep the AC current flowing through stator windings as in the PMSM motor above.

Standing in for the magnets is a concept Nikola Tesla patented in 1888: As AC current flows through various windings in the stator, the windings generate a rotating field of magnetic flux. As these magnetic lines pass through perpendicular windings on a rotor, they induce an electric current. This then generates another magnetic force that induces the rotor to turn. Because this force is only induced when the magnetic field lines cross the rotor windings, the rotor will experience no torque or force if it rotates at the same (synchronous) speed as the rotating magnetic field.

This means AC induction motors are inherently asynchronous. Rotor speed is controlled by varying the alternating current's frequency. At light loads, the inverter controlling the motor can reduce voltage to reduce magnetic losses and improve efficiency. Depowering an induction motor during cruising when it isn't needed eliminates the drag created by a permanent-magnet motor, while dual-motor EVs using PMSM motors on both axles must always power all motors. Peak efficiency may be slightly greater for BLDC or PMSM designs, but AC induction motors often achieve higher average efficiency. Another small trade-off is slightly lower starting torque than PMSM. The GM EV1 of the mid-1990s and most Teslas have employed AC Induction motors, despite skepticism about an EV revolution in some quarters.

Reluctance Motor: Think of "reluctance" as magnetic resistance: the degree to which an object opposes magnetic flux. A reluctance motor's stator features multiple electromagnet poles—concentrated windings that form highly localized north or south poles. In a switched reluctance motor (SRM), the rotor is made of soft magnetic material such as laminated silicon steel, with multiple projections designed to interact with the stator's poles. The various electromagnet poles are turned on and off in much the same way the field windings in a BLDC motor are. Using an unequal number of stator and rotor poles ensures some poles are aligned (for minimum reluctance), while others are directly in between opposite poles (maximum reluctance). Switching the stator polarity then pulls the rotor around at an asynchronous speed.

A synchronous reluctance motor (SynRM) doesn't rely on this imbalance in the rotor and stator poles. Rather, SynRM motors feature a more distributed winding fed with a sinusoidal AC current as in a PMSM design, with speed regulated by a variable-frequency drive, and an elaborately shaped rotor with voids shaped like magnetic flux lines to optimize reluctance.

The latest trend is to place small permanent magnets (often simpler ferrite ones) in some of these voids to take advantage of both magnetic and reluctance torque while minimizing cost and the back EMF (or counter-electromotive force) high-speed inefficiencies that permanent-magnet motors suffer.

Advantages include lower cost, simplicity, and high efficiency. Disadvantages can include noise and torque ripple (especially for switched reluctance motors). Toyota introduced an internal permanent-magnet synchronous reluctance motor (IPM SynRM) on the Prius, and Tesla now pairs one such motor with an AC induction motor on its Dual Motor models. Tesla also uses IPM SynRM as the single motor for its rear-drive models.

Electric motors may never sing like a small-block or a flat-plane crank Ferrari. But maybe, a decade or so from now, we'll regard the Tesla Plaid powertrain as fondly as we do those engines, even as industry leaders note that mainstream adoption faces hurdles, and every car lover will be able to describe in intimate detail what kind of motors it uses.
 

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