The Challenge of the Last Few Percent: Quantifying the Costs & Emissions Benefits of a 100% Renewable U.S. Electricity System
Only two decades ago, some scientists were skeptical we could integrate more than about 20% renewable energy generation on the U.S. power grid. But we hit that milestone in 2020 — so, these days, experts’ sights are set on finding pathways toward a fully renewable national power system. And according to new research published in Joule, the nation could get a long way toward 100% cost-effectively; it is only the final few percent of renewable generation that cause a nonlinear spike in costs to build and operate the power system.
In “Quantifying the Challenge of Reaching a 100% Renewable Energy Power System for the United States,” analysts from the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) and DOE’s Office of Energy Efficiency and Renewable Energy (EERE) evaluate possible pathways and quantify the system costs of transitioning to a 100% renewable power grid for the contiguous United States. The research was funded by EERE’s Strategic Analysis Team.
“Our goal was to robustly quantify the cost of a transition to a high-renewable power system in a way that provides electric-sector decision-makers with the information they need to assess the cost and value of pursuing such systems,” said Wesley Cole, NREL senior energy analyst and lead author of the paper.
Expanding on previous work to simulate the evolution of the U.S. power system at unprecedented scale, the authors quantify how various assumptions about how the power system might evolve can impact future system costs. They show how costs can increase nonlinearly for the last few percent toward 100%, which could drive interest in non-electric-sector investments that accomplish similar decarbonization objectives with a lower total tab.
“Our results highlight that getting all the way to 100% renewables is really challenging in terms of costs, but because the challenge is nonlinear, getting close to 100% is much easier,” Cole said. “We also show how innovations such as lower technology costs, or alternate definitions for 100% clean energy such as including nuclear or carbon capture, can lower the cost of reaching the target.”
Advanced Methods Expand Our Understanding of High-Renewable Grids
This work builds on another Joule article released last month exploring the key unresolved technical and economic challenges in achieving a 100% renewable U.S. electricity system. While some aspects of 100% renewable power grids are well established, there is much we do not know. And because 100% renewable grids do not exist at the scale of the entire United States, we rely on models to evaluate and understand possible future systems.
“With increasing reliance on energy storage technologies and variable wind and solar generation, modeling 100% renewable power systems is incredibly complex,” said Paul Denholm, NREL principal energy analyst and coauthor of the paper. “How storage was used yesterday impacts how it can be used today, and while the resolution of our renewable resource data has improved tremendously in recent years, we can’t precisely predict cloudy weather or calm winds.”
Integrated energy pathways modernizes our grid to support a broad selection of generation types, encourages consumer participation, and expands our options for transportation electrification.
Many prior studies have modeled high-renewable electricity systems for a variety of geographies, but not many examine the entire U.S. grid. And even fewer studies attempt to calculate the cost of transitioning to a 100% renewable U.S. grid — instead, they typically present snapshots of systems in a future year without considering the evolution needed to get there. This work expands on these prior studies with several important advances.
First, the team used detailed production cost modeling with unit commitment and economic dispatch to verify the results of the capacity expansion modeling performed with NREL’s publicly available Regional Energy Deployment System (ReEDS) model. The production cost model is Energy Exemplar’s PLEXOS, a commercial model widely used in the utility industry.
“Over the past couple of years we put a tremendous amount of effort into our modeling tools to give us confidence in their ability to capture the challenges inherent in 100% renewable energy power systems,” Cole said. “In addition, we also tried to consider a broad range of future conditions and definitions of the 100% requirement. The combination of these efforts enables us to quantify the cost of a transition to a 100% clean energy system far better than we could in the past.”
The analysis represents the power system with higher spatial and technology resolution than previous studies in order to better capture differences in technology types, renewable energy resource profiles, siting and land-use constraints, and transmission challenges. The analysis also uniquely captures the ability to retrofit existing fossil plants to serve needs under 100% renewable scenarios and assesses whether inertial response can be maintained in these futures.
What Drives System Costs? Transition Speed, Capital Costs, and How We Define 100%
The team simulated a total of 154 different scenarios for achieving up to 100% renewable electricity to determine how the resulting system cost changes under a wide range of future conditions, timeframes, and definitions for 100% — including with systems that allow nonrenewable low-carbon technologies to participate.
“Here we use total cumulative system cost as the primary metric for assessing the challenge of increased renewable deployment for the contiguous U.S. power system,” said Trieu Mai, NREL senior energy analyst and coauthor of the paper. “This system cost is the sum of the cost of building and operating the bulk power system assets out to the year 2050, after accounting for the time value of money.”
To establish a reference case for comparison, the team modeled the system cost at increasing renewable energy deployment for base conditions, which use midrange projections for factors such as capital costs, fuel prices, and electricity demand growth. Under these conditions, the least-cost buildout grows renewable energy from 20% of generation today to 57% in 2050, with average levelized costs of $30 per megawatt-hour (MWh). Imposing a requirement to achieve 100% renewable generation by 2050 under these same conditions raises these costs by 29%, or less than $10 per MWh. System costs increase nonlinearly for the last few percent approaching 100%
Associated with the high renewable energy targets are substantial reductions in direct carbon dioxide (CO2) emissions. From the 57% least-cost scenario, the team translated the changes in system cost and CO2 emissions between scenarios into an average and incremental levelized CO2 abatement cost. The average value is the abatement cost relative to the 57% scenario, while the incremental value is the abatement cost between adjacent scenarios, e.g., between 80% and 90% renewables. In other words, the average value considers all the changes, while the incremental value considers only the change over the most recent increment.
Total bulk power system cost at a 5% discount rate (left) for the seven base scenarios and levelized average and incremental CO2 abatement cost (right) for those scenarios. The 2050 renewable (RE) generation level for each scenario is listed on the x-axis. The system costs in the left figure are subdivided into the four cost categories listed in the figure legend (O&M = operations and maintenance). The purple diamond on the y-axis in the left plot indicates the system cost for maintaining the current generation mix, which can be used to compare costs and indicates a system cost comparable to the 90% case.
Total bulk power system cost at a 5% discount rate (left) for the seven base scenarios and levelized average and incremental CO2 abatement cost (right) for those scenarios. The 2050 renewable (RE) generation level for each scenario is listed on the x-axis. The system costs in the left figure are subdivided into the four cost categories listed in the figure legend (O&M = operations and maintenance). The purple diamond on the y-axis in the left plot indicates the system cost for maintaining the current generation mix, which can be used to compare costs and indicates a system cost comparable to the 90% case. NREL
Notably, incremental abatement costs from 99% to 100% reach $930/ton, driven primarily by the need for firm renewable capacity — resources that can provide energy during periods of lower wind and solar generation, extremely high demand, and unplanned events like transmission line outages. In many scenarios, this firm capacity was supplied by renewable-energy-fueled combustion turbines, which could run on biodiesel, synthetic methane, hydrogen, or some other renewable energy resource to support reliable power system operation. The DOE Energy Earthshots Initiative recently announced by Secretary of Energy Jennifer M. Granholm includes the Hydrogen Shot, which seeks to reduce the cost of clean hydrogen by 80% to $1 per kilogram in one decade — an ambitious effort that could help reduce the cost of providing renewable firm capacity.
“When achieving a 100% renewable system, the costs are significantly lower if there is a cost-effective source of firm capacity that can qualify for the 100% definition,” Denholm said. “The last few percent cannot cost-effectively be satisfied using only wind, solar, and diurnal storage or load flexibility — so other resources that can bridge this gap become particularly important.”
Capital costs are the largest contributor to system costs at 100% renewable energy. Future changes in the capital costs of renewable technologies and storage can thus greatly impact the total system cost of 100% renewable grids. The speed of transition is also an important consideration for both cost and emission impacts. The scenarios with more rapid transitions to 100% renewable power were more costly but had greater cumulative emissions reductions.
“Looking at the low incremental system costs in scenarios that increase renewable generation levels somewhat beyond the reference solutions to 80%–90%, we see considerable low-cost abatement opportunities within the power sector,” Mai said. “The trade-off between power-sector emissions reductions and the associated costs of reducing those emissions should be considered in the context of non-power-sector opportunities to reduce emissions, which might have lower abatement costs — especially at the higher renewable generation levels.”
“The way the requirement is defined is an important aspect of understanding the costs of the requirement and associated emissions reduction,” Cole said. “For instance, if the 100% requirement is defined as a fraction of electricity sales, as it is with current state renewable polices, the cost and emissions of meeting that requirement are similar to those of the scenarios that have requirements of less than 100%.”
Additional Research Can Help the Power Sector Understand the Path Forward
While this work relies on state-of-the-art modeling capabilities, additional research is needed to help fill gaps in our understanding of the technical solutions that could be implemented to achieve higher levels of renewable generation, and their impact on system cost. Future work could focus on key considerations such as the scaling up supply chains, social or environmental factors that could impact real-world deployment, the future role of distributed energy resources, or how increased levels of demand flexibility could reduce costs, to name a few.
“While there is much left to explore, given the energy community’s frequent focus on using the electricity sector as the foundation for economy-wide decarbonization, we believe this work extends our collective understanding of what it might take to get to 100%,” Cole said.
Learn more about NREL’s energy analysis and grid modernization research.
Article courtesy of the NREL, the U.S. Department of Energy
Porsche is rolling out three new Taycan Black Edition models. The 2026 Porsche Taycan Black Edition brings more than just a sporty new look. All three are equipped with Porsche’s Performance Battery Plus, delivering more power and a longer driving range.
Meet the 2026 Porsche Taycan Black Edition
With the new electric Macan stealing the show, Porsche is introducing new Taycan variants for the 2026 model year.
Porsche has already introduced significant upgrades for the 2025 model year, adding more driving range, faster charging, higher performance, and a sleek new design.
The new Black Edition variants will be available for the 2026 Porsche Taycan, Taycan 4, and Taycan 4S models.
Featuring its SportDesign package, the new models include high-gloss black exterior accents on the window trims and mirrors.
Other standard design elements include a rear light strip with an illuminated, blacked-out Porsche logo. Inside, the new variants include Porsche’s black interior accent package, storage package, and black brushed illuminated door sill guards.
All three Black Edition models are equipped with the larger Performance Battery Plus, which is typically offered as an option.
With a gross energy capacity of 105 kWh, Porsche says the new variants offer a longer driving range and more power. The 2025 Taycan, with the Performance Battery Plus pack, offers an EPA-estimated range of 318 miles.
On the European WLTP scale, the 2025 Porsche Taycan with the Performance Plus battery is rated with up to 679 km (421 miles) range.
The new Black Edition models are loaded with added features. Highlights include Lane Change Assist, Surround View, including Active Parking Assist, 21″ wheels with center caps featuring the full-color Porsche crest, and HD-Matrix Design LED headlights. There are even puddle light projectors that show the Porsche logo when the doors open.
On the inside, the premium features continue. The Black Edition interior features 14-way comfort seats with a memory function, a Porsche crest on the headrests, and a BOSE Surround Sound System, including Dolby Atmos, to create an immersive sound experience.
You’ll also get Porsche Electric Sport Sound, a Storage package, and the Porsche crest stitched into the leather trim. To top it off, there’s an added “Black Edition” badge in the center console, exclusive to the new variants.
Although it’s called the Black Edition, you can choose from several different colors, such as Jet Black Metallic, Volcano Grey Metallic, Dolomite Silver Metallic, and Ice Grey Metallic, at no extra cost.
Porsche will reveal prices for the 2026 Taycan Black Edition models “in due course.” Deliveries in the US are expected to begin in Fall 2025.
What do you think of the new blacked-out Taycan variants? Do you dig it? Drop us a comment below and let us know your thoughts.
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Aventon is giving its popular fat tire e-bike a serious upgrade. The company just unveiled the Aventure M, a new mid-drive version of its best-selling Aventure model. With more torque, smarter shifting, and a boost in connectivity and control, Aventon says this is the “most advanced” bike it has ever produced.
The new Aventure M swaps out the rear hub motor for a 100 Nm mid-drive motor, offering more efficient power delivery and a more natural ride feel thanks to its double-sided torque sensor. And in case that 100 Nm doesn’t exactly place it for you, just know that we’re talking about more power (or more accurately, torque) than nearly any other e-bike in this class.
The Aventon A100 motor, which is rated at 750W and runs on a 36V system, takes full advantage of its Class 3 category with pedal assist speeds up to 28 mph (45 km/h) and a throttle top speed of 20 mph (32 km/h). The throttle is sold separately, probably as a nod to being even more compliant with California’s new stricter laws regarding Class 1 and Class 3 e-bikes, which can’t have mounted throttles.
Aventon also gives riders the option to set the bike to Class 1 or 2 limits using the companion app. We’ve always been pretty impressed with Aventon’s app, as it’s quite easy to use and makes it simple to control those types of modifications to the bike.
That app pairs with Aventon’s newly developed ACU (Aventon Control Unit), a custom IoT system that adds a wide range of smart features. Riders get GPS tracking, theft detection, geofencing, remote locking, and over-the-air (OTA) firmware updates. Aventon even built in a passcode-locked on-switch for added security, as well as a physical rear-wheel lock and alarm.
We’ve previously seen Aventon use that OTA update system to give its e-bike more power via a boost feature, so the company doesn’t appear shy about pushing out new features when they’re ready.
But it’s not just about motor placement and connectivity. The Aventure M introduces electronic shifting, powered by a 10-speed Shimano CUES drivetrain and paddle shifters. Riders can shift manually or let the system take over with Auto Shift, Aventon’s torque and cadence-sensing automatic shifting mode. A new Uphill Start Assist feature gives riders an extra torque boost when starting from a stop on steep grades –perfect for off-road adventures or fully loaded cargo rides.
As for range, Aventon claims up to 85 miles (137 km) from the removable 36V 20Ah (720 Wh) battery, which itself weighs around 8.7 lbs (3.9 kg). That figure is in the lowest power level, and real-world range will depend heavily on terrain and assist level, but riders can likely expect something in the 40–60 mile (65-100 km) ballpark under typical pedaling usage when enjoying moderately higher power levels, and a bit less if leaning hard into that optional throttle.
Rounding out the build are 4-inch wide fat tires, a suspension seatpost, and an 80 mm front suspension fork. The total weight of the bike is around 73 lbs (33 kg), which is actually surprisingly reasonable for a full-featured fat tire e-bike with a mid-drive, believe it or not. Hey, these are heavy bikes when you stuff all that power, range, and tech in there.
The price at launch is US $2,899, which places the Aventure M above the hub motor version of the company’s existing Aventure model but below some other mid-drive fat tire options on the market. Aventon is clearly positioning this as a higher-performance alternative that’s still (hopefully) accessible to the average rider. It’s available now online and through Aventon’s network of over 1,800 partner dealers across the U.S.
Electrek’s Take
It’s about time we saw a major direct-to-consumer brand bring a smart tech, mid-drive fat tire e-bike to market that doesn’t require taking out a second mortgage. The Aventure M feels like a natural progression for Aventon – taking what made the Aventure 2 so popular and layering on meaningful performance and tech upgrades. The mid-drive motor brings real climbing power and smoother pedal assist, and features like auto shifting and built-in GPS tracking give this bike some serious smart credentials.
Of course, at nearly $3,000, this isn’t exactly budget territory anymore. But considering the Aventure M includes high-end components, a full-fat-tire adventure build, and an impressive level of integration, it still looks like a solid value for someone who wants their e-bike to go above and beyond the basic level of componentry and features. If the real-world range holds up and the automatic shifting works smoothly, this could easily become a category leader for anyone wanting an all-terrain e-bike that feels as refined as it is rugged. Aventon of course didn’t reinvent the wheel here — they just made a smarter, better one. I look forward to getting on one soon for a review and letting you know what I think of the ride.
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Move over, ordinary scooters – there’s a new contender packed with features that seem to rival the latest in automotive tech. Omoway, a fresh face in the electric two-wheeler space founded by former Xpeng execs, has just unveiled the Omo X, a scooter full of premium tech features that blur the lines between e-scooter and self-driving EV.
At its recent launch in Jakarta, the Omo X didn’t just sit pretty center stage, it actually drove itself onto the stage using its “Halo Pilot” system, which apparently comes complete with adaptive cruise control, remote summon, self-parking, and even automatic reversing and self-balancing at low speeds. This is legit autonomous behavior previously reserved for cars, now shrunk down and smoothed out for a two-wheeler.
Under the hood – or rather, behind the sleek bodywork – Omoway’s Halo architecture delivers collision warning, emergency-brake assist, blind spot monitoring, and V2V communication.
The frame is modular, too. It can be reconfigured in step-through, straddle, or touring posture to suit casual riders, commuters, and motorcycle wannabes alike. That kind of flexibility isn’t just a marketing gimmick, but rather it looks purpose-built to capture diverse motorcycle-heavy markets like Indonesia, which counts over 120 million two-wheelers and is quickly transitioning to electric models, with sales surging nearly 400% in 2024, though adoption remains early-stage.
We don’t have full specs or pricing yet, but early reports point to a launch in early 2026, with a projected price around €3,500 (roughly $3,800), positioning it above entry-level but below premium e-moto territory. That puts Omoway in a unique space: not asking riders to settle for barebones utility, but also not charging premium-badge luxury pricing either.
So what’s the trade-off?
On the plus side, the Omo X is the boldest statement we’ve seen from a fresh OEM in years. It’s tech-rich, head-turning, and seems built to evolve with software updates. The remote summon and AI-assisted features could genuinely simplify urban mobility, and tricks like automatically driving itself to a charging station sound legitimately useful.
But bleeding-edge autonomous tech like that also threatens to weigh it down, somewhat literally, but more so conceptually. Even “normal” modern electric scooters can face headwinds in production, and they aren’t exactly reinventing the wheel with self-driving or self-balancing. Omoway’s vision here will have to carry extra sensors, actuators, and redundant systems to support those smart functions. With added costs and complexity, will riders in developing markets pay a premium, carry extra maintenance risk, or worry about obsolescence? Much hinges on Omoway’s software support and local service networks.
Then there’s the question of necessity. Southeast Asian scooter culture prizes simplicity, affordability, and ruggedness – features not always associated with cutting-edge tech bundles. And in regions like North America or Europe, where EV scooter culture is small yet growing and infrastructure isn’t universal, adoption may hinge on support for charging, service, and safety standards.
Still, this is a bold move from a brand that isn’t afraid to think big will always be refreshing. With a seed round backed by Sequoia and ZhenFund, plus a team sourced from Xpeng and automotive-grade supply chains, Omoway clearly has both the ambition and capacity to scale. And while Indonesia may have been the launchpad, global markets aren’t off the table.
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