Opinion | Why Electric Mail Trucks Are the Way of the Future


US Postal Service Trucks

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USPS Electric Mail Trucks promise zero-emission delivery, lower lifecycle and maintenance costs, and cleaner air. Congressional funding in Build Back Better would modernize the EV fleet and expand charging infrastructure, improving public health nationwide.

 

Key Points

USPS Electric Mail Trucks are zero-emission delivery vehicles that cut costs, reduce pollution, and improve health.

✅ Lower lifetime fuel and maintenance costs vs gas trucks

✅ Cuts greenhouse gas and NOx emissions in communities

✅ Expands charging infrastructure via federal investments

 

The U.S. Postal Service faces serious challenges, with billions of dollars in annual losses and total mail volume continuing to decline. Meanwhile, Congress is constantly hamstringing the agency.

But now lawmakers have an opportunity to invest in the Postal Service in a way that would pay dividends for years to come: By electrifying the postal fleet.

Tucked inside the massive social spending and climate package lumbering through the Senate is money for new, cleaner postal delivery trucks. There’s a lot to like about electric postal trucks. They’d significantly improve Americans’ health while also slowing climate change. And it just makes sense for taxpayers over the long term; the Postal Service’s private sector competitors have already made similar investments, as EV adoption reaches an EV inflection point in the market. As Democrats weigh potential areas to cut in President Joe Biden’s Build Back Better plan, this is one provision that should escape the knife.

To call the U.S. Postal Service’s current vehicles “clunkers” would be an understatement. These often decades-old trucks are famous for having no airbags, no air conditioning and a nasty habit of catching fire. So the Postal Service’s recent decision to buy 165,000 replacement trucks is basically a no-brainer. But the main question is whether they will run on electricity or gasoline.

Electric vehicles are newer to the market and still carry a higher sticker price, as seen with electric bus adoption in many cities. But that higher price buys concrete benefits, like lower lifetime fuel and maintenance costs and huge reductions in pollution. Government demand for electric trucks will also push private markets to create better, cheaper vehicles, directly benefiting consumers. So while buying electric postal trucks may be somewhat more costly at first, over the long term, failing to do so could be far costlier.

At some level, this is a straightforward business decision that the Postal Service’s competitors have already made. For instance, Amazon has already deployed some of the 100,000 electric vans it recently ordered, and FedEx has promised a fully electric ground fleet by 2040, while nonprofit investment in electric trucks is accelerating electrification at major ports. In a couple of decades, the Postal Service could be the only carrier still driving dirty gas guzzlers, buying expensive fuel and paying the higher maintenance costs that combustion engines routinely require. Consumers could flock to greener competitors.

Beyond these business advantages, zero-emission vehicles carry other big benefits for the public. The Postal Service recently calculated some of these benefits by estimating the climate harms that going all-electric would avoid, benefits that persist even where electricity generation still includes fossil-generated electricity in nearby grids. Its findings were telling: A fully electric fleet would prevent millions or tens of millions of dollars’ worth of climate-change-related harms to property and human health each year of the trucks’ lifetimes (and this is probably a considerable underestimate). The world leaders that recently gathered at the global climate summit in Glasgow encouraged exactly this type of transition toward low-carbon technologies.

A cleaner postal fleet would benefit Americans in many other important ways. In addition to warming the planet, tailpipe pollutants can have dire health consequences for the people who breathe in the fumes. Mail trucks traverse virtually every neighborhood in the country and often must idle in residential areas, so we all benefit when they stop emitting. And these localized harms are not distributed equally. Some parts of the country — too often, low-income communities of color — already have poor air quality. Removing pollution from dirty mail trucks will especially help these overburdened and underserved populations.

The government’s purchasing power also routinely inspires companies to devise better and cheaper ways to do business. Investments in aerospace technologies, for instance, have spilled over into consumer innovations, giving us GPS technologies and faster, more fuel-efficient passenger jets. Bulk demand for cleaner trucks could inspire similar innovations as companies clamor for government contracts, meaning we all could get cheaper and better green products like car batteries, and the American EV boom could further accelerate those gains.

Additionally, because postal trucks are virtually everywhere in the country, if they go electric, that would mean more charging stations and grid updates everywhere too, and better utility planning for truck fleets to ensure reliable service. Suddenly, that long road trip that discourages many would-be electric car buyers may be simpler, which could boost electric vehicle adoption.

White House climate adviser Gina McCarthy talks with EVgo CEO Cathy Zoi before the start of an event near an EVgo electric car charging station.
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The case for electrifying the postal fleet is strong from both a business and a social standpoint. Indeed, even Postmaster General Louis DeJoy, who was appointed during the Trump administration, supports it. But getting there is not so simple. Most private businesses could just borrow the money they need for this investment and pay it back with the long-term savings they would enjoy. But not the Postal Service. Thanks to its byzantine funding structure, it cannot afford electric trucks’ upfront costs unless Congress either provides the money or lets it borrow more. This is the primary reason it has not committed to making more than 10 percent of its fleet electric.

And that returns us to the Build Back Better legislation. The version passed by the House sets aside $7 billion to help the Postal Service buy electric mail trucks — enough to electrify the vast majority of its fleet by the end of the decade.

Biden has made expanding the use of electric vehicles a top priority, setting an ambitious goal of 100 percent zero-emission federal vehicle acquisitions by 2035, and new EPA emission limits aim to accelerate EV adoption. But Sen. Joe Manchin has expressed resistance to some of the climate-related subsidies in the legislation and is also eager to keep costs down. This provision, however, is worthy of the West Virginia Democrat’s support.

Most Americans would see — and benefit from — these trucks on a daily basis. And for an operation that got its start under Benjamin Franklin, it’s a crucial way to keep the Postal Service relevant.

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YVR welcomes government funding for new Electric Vehicle Chargers

YVR EV Charging Infrastructure Funding backs new charging stations at Vancouver International Airport via ZEVIP and CleanBC Go Electric, supporting Net Zero 2030 with Level 2 and DC fast charging across Sea Island.

 

Key Points

A federal and provincial effort to expand EV charging at YVR, accelerating airport electrification toward Net Zero 2030.

✅ Up to 74 new EV charging outlets across Sea Island by 2025

✅ Funded through ZEVIP and CleanBC Go Electric programs

✅ Supports passengers, partners, and YVR fleet electrification

 

Vancouver International Airport (YVR) welcomes today’s announcement from the Government of Canada, which confirms new federal funding under Natural Resource Canada’s Zero Emission Vehicle Infrastructure Program (ZEVIP) and broader zero-emission vehicle incentives for essential infrastructure at the airport that will further enable YVR to achieve its climate targets.

This federal funding, combined with funding through the Government of British Columbia’s CleanBC Go Electric program, which includes EV charger rebates, will support the installation of up to 74 additional Electric Vehicle (EV) Charging outlets across Sea Island over the next three years. EV charging infrastructure is identified as a key priority in the airport’s Roadmap to Net Zero 2030. It is also an important part of its purpose in being a Gateway to the New Economy.

“We know that our passengers’ needs and expectations are changing as EV adaptation increases across our region and policies like the City’s EV-ready requirements take hold, we are always working hard to anticipate and exceed these expectations and provide world-class amenities at our airport,” said Tamara Vrooman, President & CEO, Vancouver Airport Authority.

This airport initiative is among 26 projects receiving $19 million under ZEVIP, which assists organizations as they adapt to the Government of Canada’s mandatory target for all new light-duty cars and passenger trucks to be zero-emission by 2035, and to provincial momentum such as B.C.'s EV charging expansion across the network.

“We are grateful to have found partners at all levels of government as we take bold action to become the world’s greenest airport. Not only will this critical funding support us as we work to the complete electrification of our airport operations, and as regional innovations like Harbour Air’s electric aircraft demonstrate what’s possible, but it will help us in our role supporting the mutual needs of our business partners related to climate action,” Vrooman continued.

These new EV Charging stations are planned to be installed by 2025, and will provide electricity to the YVR fleet, commercial and business partners’ vehicles, as well as passengers and the public, complementing BC Hydro’s expanding charging network in southern B.C. Currently, YVR provides 12 free electric vehicle charging stalls (Level Two) at its parking facilities, as well as one DC fast-charging stall.

This exciting announcement comes on the heels of the Province of BC’s Integrated Marketplace Initiative (IMI) pilot program in November 2022, a partnership between YVR and the Province of British Columbia to invest up to 11.5 million to develop made-in-BC clean-tech solutions for use at the airport, and related programs offering home and workplace charging rebates are accelerating adoption.

 

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California's Looming Green New Car Wreck

California Gas Car Ban 2035 signals a shift to electric vehicles, raising grid reliability concerns, charging demand, and renewable energy challenges across solar, wind, and storage, amid rolling blackouts and carbon-free power mandates.

 

Key Points

An order ending new gasoline car sales by 2035 in California, accelerating EV adoption and pressuring the power grid.

✅ 25% EV fleet could add 232.5 GWh/day charging demand by 2040

✅ Solar and wind intermittency strains nighttime home charging

✅ Grid upgrades, storage, and load management become critical

 

On September 23, California Gov. Gavin Newsom issued an executive order that will ban the sale of gasoline-powered cars in the Golden State by 2035. Ignoring the hard lessons of this past summer, when California’s solar- and wind-reliant electric grid underwent rolling blackouts, Newsom now adds a huge new burden to the grid in the form of electric vehicle charging, underscoring the need for a much bigger grid to meet demand. If California officials follow through and enforce Newsom’s order, the result will be a green new car version of a train wreck.

In parallel, the state is moving on fleet transitions, allowing electric school buses only from 2035, which further adds to charging demand.

Let’s run some numbers. According to Statista, there are more than 15 million vehicles registered in California. Per the U.S. Department of Energy, there are only 256,000 electric vehicles registered in the state—just 1.7 percent of all vehicles, a share that will challenge state power grids as adoption grows.

Using the Tesla Model3 mid-range model as a baseline for an electric car, you’ll need to use about 62 kilowatt-hours (KWh) of power to charge a standard range Model 3 battery to full capacity. It will take about eight hours to fully charge it at home using the standard Tesla NEMA 14-50 charger, a routine that has prompted questions about whether EVs could crash the grid by households statewide.

Now, let’s assume that by 2040, five years after the mandate takes effect, also assuming no major increase in the number of total vehicles, California manages to increase the number of electric vehicles to 25 percent of the total vehicles in the state. If each vehicle needs an average of 62 kilowatt-hours for a full charge, then the total charging power required daily would be 3,750,000 x 62 KWh, which equals 232,500,000 KWh, or 232.5 gigawatt-hours (GWh) daily.

Utility-scale California solar electric generation according to the energy.ca.gov puts utility-scale solar generation at about 30,000 GWh per year currently. Divide that by 365 days and we get 80 GWh/day, predicted to double, to 160 GWh /day. Even if we add homeowner rooftop solar, and falling prices for solar and home batteries in the wake of blackouts, about half the utility-scale, at 40 GWh/day we come up to 200 GW/h per day, still 32 GWh short of the charging demand for a 25% electric car fleet in California. Even if rooftop solar doubles by 2040, we are at break-even, with 240GWh of production during the day.

Bottom-line, under the most optimistic best-case scenario, where solar operates at 100% of rated capacity (it seldom does), it would take every single bit of the 2040 utility-scale solar and rooftop capacity just to charge the cars during the day. That leaves nothing left for air conditioning, appliances, lighting, etc. It would all go to charging the cars, and that’s during the day when solar production peaks.

But there’s a much bigger problem. Even a grade-schooler can figure out that solar energy doesn’t work at night, when most electric vehicles will be charging at homes, even as some officials look to EVs for grid stability through vehicle-to-grid strategies. So, where does Newsom think all this extra electric power is going to come from?

The wind? Wind power lags even further behind solar power. According to energy.gov, as of 2019, California had installed just 5.9 gigawatts of wind power generating capacity. This is because you need large amounts of land for wind farms, and not every place is suitable for high-return wind power.

In 2040, to keep the lights on with 25 percent of all vehicles in California being electric, while maintaining the state mandate requiring all the state’s electricity to come from carbon-free resources by 2045, California would have to blanket the entire state with solar and wind farms. It’s an impossible scenario. And the problem of intermittent power and rolling blackouts would become much worse.

And it isn’t just me saying this. The U.S. Environmental Protection Agency (EPA) agrees. In a letter sent by EPA Administrator Andrew Wheeler to Gavin Newsom on September 28, Wheeler wrote:

“[It] begs the question of how you expect to run an electric car fleet that will come with significant increases in electricity demand, when you can’t even keep the lights on today.

“The truth is that if the state were driving 100 percent electric vehicles today, the state would be dealing with even worse power shortages than the ones that have already caused a series of otherwise preventable environmental and public health consequences.”


California’s green new car wreck looms large on the horizon. Worse, can you imagine electric car owners’ nightmares when California power companies shut off the power for safety reasons during fire season? Try evacuating in your electric car when it has a dead battery.

Gavin Newsom’s “no more gasoline cars sold by 2035” edict isn’t practical, sustainable, or sensible, much like the 2035 EV mandate in Canada has been criticized by some observers. But isn’t that what we’ve come to expect with any and all of these Green New Deal-lite schemes?

 

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Can food waste be turned into green hydrogen to produce electricity?

Food Waste to Green Hydrogen uses biological production to create clean energy, enabling waste-to-energy, decarbonization, and renewable hydrogen for electricity, industrial processes, and transport fuels, developed at Purdue University Northwest with Purdue Research Foundation licensing.

 

Key Points

A biological process converting food waste into renewable hydrogen for clean energy, electricity, industry, and transport.

✅ Enables rapid, scalable waste-to-hydrogen deployment

✅ Supports grid power, industrial heat, and mobility fuels

✅ Backed by patents, DOE grants, and licensing deals

 

West Lafayette, Indiana-based Purdue Research Foundation recently completed a licensing agreement with an international energy company – the name of which was not disclosed – for the commercialization of a new process discovered at Purdue University Northwest (PNW) for the biological production of green hydrogen from food waste. A second licensing agreement with a company in Indiana is under negotiation.


Food waste into green hydrogen
Researchers say that this new process, which uses food waste to biologically produce hydrogen, can be used as a clean energy source for producing electricity, as well as for chemical and industrial processes like green steel production or as a transportation fuel.

Robert Kramer, professor of physics at PNW and principal investigator for the research, says that more than 30% of all food, amounting to $48 billion, is wasted in the United States each year. That waste could be used to create hydrogen, a sustainable energy source alongside municipal solid waste power options. When hydrogen is combusted, the only byproduct is water vapor.

The developed process has a high production rate and can be implemented quickly to support large H2 energy systems in practice. The process is robust, reliable, and economically viable for local energy production and processes.

The research team has received five grants from the US Department of Energy and the Purdue Research Foundation totaling around $800,000 over the last eight years to develop the science and technology that led to this process, much like advances in advanced nuclear reactors drive clean energy innovation.

Two patents have been issued, and a third patent is currently in the final stages of approval. Over the next nine months, a scale-up test will be conducted, reflecting how power-to-gas storage can integrate with existing infrastructure. Based upon test results, it is anticipated that construction could start on the first commercial prototype within a year.

Last week, a facility designed to turn non-recyclable plastics into green hydrogen was approved in the UK, as other innovations like the seawater power concept progress globally. It is the second facility of its kind there.

 

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Reversing the charge - Battery power from evs to the grid could open a fast lane

Vehicle-to-Grid V2G unlocks EV charging flexibility and grid services, integrating renewable energy, demand response, and peak shaving to displace stationary storage and firm generation while lowering system costs and enhancing reliability.

 

Key Points

Vehicle-to-Grid V2G lets EV batteries discharge to grid, balancing renewables and cutting storage and firm generation.

✅ Displaces costly stationary storage and firm generation

✅ Enables demand response and peak shaving at scale

✅ Supports renewable integration and grid reliability

 

Owners of electric vehicles (EVs) are accustomed to plugging into charging stations at home and at work and filling up their batteries with electricity from the power grid. But someday soon, when these drivers plug in, their cars will also have the capacity to reverse the flow and send electrons back to the grid. As the number of EVs climbs, the fleet’s batteries could serve as a cost-effective, large-scale energy source, with potentially dramatic impacts on the energy transition, according to a new paper published by an MIT team in the journal Energy Advances.

“At scale, vehicle-to-grid (V2G) can boost renewable energy growth, displacing the need for stationary energy storage and decreasing reliance on firm [always-on] generators, such as natural gas, that are traditionally used to balance wind and solar intermittency,” says Jim Owens, lead author and a doctoral student in the MIT Department of Chemical Engineering. Additional authors include Emre Gençer, a principal research scientist at the MIT Energy Initiative (MITEI), and Ian Miller, a research specialist for MITEI at the time of the study.

The group’s work is the first comprehensive, systems-based analysis of future power systems, drawing on a novel mix of computational models integrating such factors as carbon emission goals, variable renewable energy (VRE) generation, and costs of building energy storage, production, and transmission infrastructure.

“We explored not just how EVs could provide service back to the grid — thinking of these vehicles almost like energy storage on wheels providing flexibility — but also the value of V2G applications to the entire energy system and if EVs could reduce the cost of decarbonizing the power system,” says Gençer. “The results were surprising; I personally didn’t believe we’d have so much potential here.”

Displacing new infrastructure

As the United States and other nations pursue stringent goals to limit carbon emissions, electrification of transportation has taken off, with the rate of EV adoption rapidly accelerating. (Some projections show EVs supplanting internal combustion vehicles over the next 30 years.) With the rise of emission-free driving, though, there will be increased demand for energy on already stressed state power grids nationwide. “The challenge is ensuring both that there’s enough electricity to charge the vehicles and that this electricity is coming from renewable sources,” says Gençer.

But solar and wind energy is intermittent. Without adequate backup for these sources, such as stationary energy storage facilities using lithium-ion batteries, for instance, or large-scale, natural gas- or hydrogen-fueled power plants, achieving clean energy goals will prove elusive. More vexing, costs for building the necessary new energy infrastructure runs to the hundreds of billions.

This is precisely where V2G can play a critical, and welcome, role, the researchers reported. In their case study of a theoretical New England power system meeting strict carbon constraints, for instance, the team found that participation from just 13.9 percent of the region’s 8 million light-duty (passenger) EVs displaced 14.7 gigawatts of stationary energy storage. This added up to $700 million in savings — the anticipated costs of building new storage capacity.

Their paper also described the role EV batteries could play at times of peak demand, such as hot summer days. “With proper grid coordination practices in place, V2G technology has the ability to inject electricity back into the system to cover these episodes, so we don’t need to install or invest in additional natural gas turbines,” says Owens. “The way that EVs and V2G can influence the future of our power systems is one of the most exciting and novel aspects of our study.”

Modeling power

To investigate the impacts of V2G on their hypothetical New England power system, the researchers integrated their EV travel and V2G service models with two of MITEI’s existing modeling tools: the Sustainable Energy System Analysis Modeling Environment (SESAME) to project vehicle fleet and electricity demand growth, and GenX, which models the investment and operation costs of electricity generation, storage, and transmission systems. They incorporated such inputs as different EV participation rates, costs of generation for conventional and renewable power suppliers, charging infrastructure upgrades, travel demand for vehicles, changes in electricity demand, and EV battery costs.

Their analysis found benefits from V2G applications in power systems (in terms of displacing energy storage and firm generation) at all levels of carbon emission restrictions, including one with no emissions caps at all. However, their models suggest that V2G delivers the greatest value to the power system when carbon constraints are most aggressive — at 10 grams of carbon dioxide per kilowatt hour load. Total system savings from V2G ranged from $183 million to $1,326 million, reflecting EV participation rates between 5 percent and 80 percent.

“Our study has begun to uncover the inherent value V2G has for a future power system, demonstrating that there is a lot of money we can save that would otherwise be spent on storage and firm generation,” says Owens.


Harnessing V2G

For scientists seeking ways to decarbonize the economy, the vision of millions of EVs parked in garages or in office spaces and plugged into the grid via vehicle-to-building charging for 90 percent of their operating lives proves an irresistible provocation. “There is all this storage sitting right there, a huge available capacity that will only grow, and it is wasted unless we take full advantage of it,” says Gençer.

This is not a distant prospect. Startup companies are currently testing software that would allow two-way communication between EVs and grid operators or other entities. With the right algorithms, EVs would charge from and dispatch energy to the grid according to profiles tailored to each car owner’s needs, never depleting the battery and endangering a commute.

“We don’t assume all vehicles will be available to send energy back to the grid at the same time, at 6 p.m. for instance, when most commuters return home in the early evening,” says Gençer. He believes that the vastly varied schedules of EV drivers will make enough battery power available to cover spikes in electricity use over an average 24-hour period. And there are other potential sources of battery power down the road, such as electric school buses that are employed only for short stints during the day and then sit idle, with the potential to power buildings during peak hours.

The MIT team acknowledges the challenges of V2G consumer buy-in. While EV owners relish a clean, green drive, they may not be as enthusiastic handing over access to their car’s battery to a utility or an aggregator working with power system operators. Policies and incentives would help.

“Since you’re providing a service to the grid, much as solar panel users do, you could get paid to sell electricity back for your participation, and paid at a premium when electricity prices are very high,” says Gençer.

“People may not be willing to participate ’round the clock, but as states like California explore EVs for grid stability programs and incentives, if we have blackout scenarios like in Texas last year, or hot-day congestion on transmission lines, maybe we can turn on these vehicles for 24 to 48 hours, sending energy back to the system,” adds Owens. “If there’s a power outage and people wave a bunch of money at you, you might be willing to talk.”

“Basically, I think this comes back to all of us being in this together, right?” says Gençer. “As you contribute to society by giving this service to the grid, you will get the full benefit of reducing system costs, and also help to decarbonize the system faster and to a greater extent.”


Actionable insights

Owens, who is building his dissertation on V2G research, is now investigating the potential impact of heavy-duty electric vehicles in decarbonizing the power system. “The last-mile delivery trucks of companies like Amazon and FedEx are likely to be the earliest adopters of EVs,” Owen says. “They are appealing because they have regularly scheduled routes during the day and go back to the depot at night, which makes them very useful for providing electricity and balancing services in the power system.”

Owens is committed to “providing insights that are actionable by system planners, operators, and to a certain extent, investors,” he says. His work might come into play in determining what kind of charging infrastructure should be built, and where.

“Our analysis is really timely because the EV market has not yet been developed,” says Gençer. “This means we can share our insights with vehicle manufacturers and system operators — potentially influencing them to invest in V2G technologies, avoiding the costs of building utility-scale storage, and enabling the transition to a cleaner future. It’s a huge win, within our grasp.”

 

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California allows electric school buses only from 2035

California Electric School Bus Mandate 2035 sets zero-emission requirements, outlines funding, state reimbursement, fleet electrification, infrastructure, and cost estimates, highlighting exemptions for frontier districts and alignment with clean transportation and climate policy goals.

 

Key Points

California's 2035 policy requires all new school buses be zero-emission, with funding and limited rural exemptions.

✅ Mandates zero-emission purchases for new school buses from 2035

✅ Estimates $5B transition cost with state reimbursement support

✅ Frontier districts may apply for 5-year extensions

 

California Governor Gavin Newsom has signed a new legislation requiring that from 2035, all newly ordered or contracted school buses must be zero-emission, a move aligned with California's push for expanded EV grid capacity statewide.

The state estimates that switching to electric school buses will cost around five billion dollars over the next decade, a projection reflecting electric bus challenges seen globally. That is because a diesel equivalent costs about 200,000 dollars less than a battery-electric version, as highlighted by critical analyses of California policy. And “the California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state.”

There are about 23,800 school buses on the road in California. About 500 are already electric, with conversion initiatives expected to expand the total, and 2,078 electric buses have been ordered.

There are – as always- exceptions to the rule. So-called “frontier districts,” which have less than 600 students or are in a county with a population density of less than ten persons per square mile, can file for a five-year extension, drawing on lessons from large electric bus fleets about route length and charging constraints. However, they must “reasonably demonstrate that a daily planned bus route for transporting pupils to and from school cannot be serviced through available zero-emission technology in 2035.”

Califonia is the fifth US state to mandate electric school buses, and jurisdictions like British Columbia are deploying electric school buses as well. Connecticut, Maryland, Maine, and New York implemented similar legislation, while California continues broader zero-emission freight adoption with Volvo VNR electric trucks entering service across the state.

 

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Solar and wind power curtailments are rising in California

CAISO Renewable Curtailments reflect grid balancing under transmission congestion and oversupply, reducing solar and wind output while leveraging WEIM trading, battery storage, and transmission expansion to integrate renewables and stabilize demand-supply.

 

Key Points

CAISO renewable curtailments are reductions in wind and solar output to balance grid amid congestion or oversupply.

✅ Driven mainly by transmission congestion, less by oversupply.

✅ Peaks in spring when demand is low and solar output is high.

✅ Mitigated by WEIM trades, new lines, and battery storage growth.

 

The California Independent System Operator (CAISO), the grid operator for most of the state, is increasingly curtailing solar- and wind-powered electricity generation, as reported in rising curtailments, as it balances supply and demand during the rapid growth of wind and solar power in California.

Grid operators must balance supply and demand to maintain a stable electric system as advances in solar and wind continue to scale. The output of wind and solar generators are reduced either through price signals or rarely, through an order to reduce output, during periods of:

Congestion, when power lines don’t have enough capacity to deliver available energy
Oversupply, when generation exceeds customer electricity demand

In CAISO, curtailment is largely a result of congestion. Congestion-related curtailments have increased significantly since 2019 because California's solar boom has been outpacing upgrades in transmission capacity.

In 2022, CAISO curtailed 2.4 million megawatthours (MWh) of utility-scale wind and solar output, a 63% increase from the amount of electricity curtailed in 2021. As of September, CAISO has curtailed more than 2.3 million MWh of wind and solar output so far this year, even as the US project pipeline is dominated by wind, solar, and batteries.

Solar accounts for almost all of the energy curtailed in CAISO—95% in 2022 and 94% in the first seven months of 2023. CAISO tends to curtail the most solar in the spring when electricity demand is relatively low (because moderate spring temperatures mean less demand for space heating or air conditioning) and solar output is relatively high, although wildfire smoke impacts can reduce available generation during fire season as well.

CAISO has increasingly curtailed renewable generation as renewable capacity has grown in California, and the state has even experienced a near-100% renewables moment on the grid in recent years. In 2014, a combined 9.0 gigawatts (GW) of wind and solar capacity had been built in California. As of July 2023, that number had grown to 17.6 GW. Developers plan to add another 3.0 GW by the end of 2024.

CAISO is exploring and implementing various solutions to its increasing curtailment of renewables, including:

The Western Energy Imbalance Market (WEIM) is a real-time market that allows participants outside of CAISO to buy and sell energy to balance demand and supply. In 2022, more than 10% of total possible curtailments were avoided by trading within the WEIM. A day ahead market is expected to be operational in Spring 2025.

CAISO is expanding transmission capacity to reduce congestion. CAISO’s 2022–23 Transmission Planning Process includes 45 transmission projects to accommodate load growth and a larger share of generation from renewable energy sources.

CAISO is promoting the development of flexible resources that can quickly respond to sudden increases and decreases in demand such as battery storage technologies that are rapidly becoming more affordable. California has 4.9 GW of battery storage, and developers plan to add another 7.6 GW by the end of 2024, according to our survey of recent and planned capacity changes. Renewable generators can charge these batteries with electricity that would otherwise have been curtailed.

 

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