Today’s deep dive looks at one of the most disruptive - and misunderstood - ideas in energy.

For decades, planners assumed that renewable power could only replace fossil fuels if it was perfectly balanced with vast amounts of storage. But as solar and wind costs have collapsed, a new paradigm is emerging: deliberately building more capacity than we ‘need’ may actually be the cheapest, fastest, and most reliable path to a 100% clean grid.

In this essay, we evaluate the evidence. Drawing on peer-reviewed studies, IEA PVPS reports, and cutting-edge system models, we examine whether the science supports RethinkX’s bold claim of Stellar Energy superabundance. The findings are clear: overbuilding renewables is not waste — it’s the cornerstone of a post-scarcity energy future.

Overbuilding Renewables as a New Paradigm

RethinkX’s Stellar Energy report, which we explored in-depth here at AoT, envisions a world of “clean energy superabundance” achieved by massively deploying solar, wind, and battery systems (Dorr et al., 2025) Central to this vision is the strategy of overbuilding renewable capacity – deliberately installing more solar and wind power than needed for average demand – and then using the excess generation at times of surplus. This approach runs counter to traditional power planning, but it is gaining traction as the costs of renewables plummet. Indeed, recent research suggests that building more renewable generation than strictly necessary can lower overall system costs and ensure round-the-clock reliability.

The key question is whether the scientific literature supports RethinkX’s bold claim that such overbuilding can usher in an era of essentially unlimited, near-zero marginal cost energy. Below, we dive deep into current research on overbuilding renewables – examining its feasibility, cost-effectiveness, and implications – to evaluate how it aligns with the Stellar Energy analysis.

Overbuilding vs. Storage: Finding the Cost Sweet Spot

A fundamental challenge of 100% renewable energy is dealing with variability in supply. Solar and wind output fluctuate daily and seasonally, creating periods of surplus and periods of deficit relative to demand. Traditionally, achieving reliable 24/7 power with renewables was thought to require massive energy storage (e.g. big battery banks or other storage technologies) to save excess power for later use. However, storing energy for weeks or months (to cover winter solar lulls or multi-day wind droughts) becomes extremely expensive and resource-intensive.

Overbuilding renewable capacity offers an alternate pathway: by installing surplus generation, one can produce extra energy during favorable conditions and simply curtail the unused portion, thereby reducing the required storage to much more manageable levels (Perez et al., 2019). The excess capacity acts as “implicit storage” – it’s available as a buffer to meet demand when renewable output would otherwise be too low, effectively substituting for some of the storage or backup generation that would be needed in a perfectly balanced system (ASES, 2023).

Crucially, the economic trade-off between overcapacity and storage has shifted in recent years. Solar photovoltaic (PV) costs have declined so rapidly that adding extra PV panels is often cheaper than building equivalent storage for the same energy buffer. As we previously noted at AoT, a rigorous 2023 analysis by the IEA Photovoltaic Power Systems Programme (PVPS) concluded that a 100% renewable electricity system is both feasible and cost-effective if it includes strategic overbuilding of wind and solar capacity (IEA PVPS, 2023). Overbuilding “even a little” dramatically reduces the amount (and cost) of storage needed to handle renewables’ intermittency. By contrast, a system that avoids curtailment and tries to store every excess kilowatt-hour would require on the order of ten times more storage, raising costs far above economic viability. As one research report put it, “using only battery storage as a solution to solar variability would push system costs far above grid parity”, whereas oversizing generation and curtailing output cuts storage needs by an order of magnitude (Perez et al., 2019). In other words, there is a sweet spot on the cost curve: a balance where some level of curtailment (i.e. some oversupply of renewables that is not used) minimizes total system cost by avoiding the exponentially increasing expense of firming every last drop of energy with storage (Wang et al., 2021).

According to these studies, this cost-optimal point typically involves a substantial share of renewable generation being curtailed. Where RethinkX differs is in pointing out that curtailment is unnecessary – surplus energy should be harness for multiple practical applications and services.

From the more conventional framework, how much curtailment is ideal? Many studies suggest that allowing a surprisingly large fraction of renewable output to go unused can be economically optimal. For example, an in-depth modeling for California’s grid found that the lowest-cost 100% renewable solution came when 25-43% of total annual renewable electricity produced was curtailed in an overbuild scenario. This strategy – essentially overbuilding wind and solar by roughly one-third or more – reduced total system costs by a factor of three compared to a scenario with no curtailment (which required vastly more storage). In dollar terms, curtailment saves trillions: about $1.8 trillion vs. $5.2 trillion in cumulative investment through 2045 for California’s fully decarbonized power system, by avoiding over-reliance on batteries (Wang et al., 2021). These findings align with the “Clean Energy U-Curve” concept invoked by RethinkX: at one end, too little renewable capacity causes high fuel/storage costs, while at the other extreme, gross overbuild would waste capital – but in between lies a broad minimum-cost zone where building somewhat more capacity than needed yields the cheapest and most reliable power.

Importantly, the location of this optimal point is dynamic – it depends on relative technology costs. As the price of renewables falls faster than the price of storage (as has been the case historically, especially for solar PV vs. lithium batteries), the economically optimal degree of overbuild increases. In the last decade, solar module prices dropped so dramatically that it now can cost less to build an entire new solar farm than to keep fueling and operating a coal power plant. Thanks to these trends, we have essentially arrived at an inflection point in energy economics: for the first time in history, it makes financial sense to plan for excess generating infrastructure (i.e. deliberate overcapacity) because the energy it produces is so cheap (ASES, 2023). In a 100% renewables scenario, both the economic cost and the environmental impact turn out lower when we build more solar and wind than needed on an annual energy basis, rather than trying to match supply exactly to demand with costly storage or fossil backup. This paradigm shift – that “wasting” some clean energy can be the most cost-effective approach – underpins the concept of clean energy superabundance championed by RethinkX.

Evidence from Recent Studies on Overbuilding

Numerous studies across different regions and scales have converged on the conclusion that overbuilding renewable capacity, coupled with proactive curtailment, is a key enabler of low-cost, reliable clean power. This section highlights a selection of findings from the scientific literature:

• Minnesota “Solar Pathways” Study (2018–2019): A detailed analysis for the U.S. state of Minnesota explored pathways to provide firm (24/7) power with renewables. Oversizing the PV and wind capacity and dynamically curtailing excess generation emerged as the least-cost strategy to meet demand year-round. By optimally overbuilding, the researchers reduced the needed battery storage by about a factor of ten compared to a scenario that relied on storage alone (Perez et al., 2019). In effect, every $1 spent on extra PV/wind saved much more than $1 of storage costs. The study’s authors concluded that “proactive curtailment strategies should inform future [energy] planning” if we aim to achieve firm, affordable renewable electricity. Notably, the lowest-cost mix for Minnesota included about 5% of energy from existing natural gas plants as a reliability cushion, but even 95%+ renewable supply was achievable at costs comparable to today’s grid. This illustrates that allowing a tiny fraction of fuel-fired backup (or conversely, a tolerable amount of unserved load) can drastically reduce the overbuild required for 100% absolute coverage – though in principle, further overbuilding could eliminate the gas entirely if desired.
• IEA PVPS “Firm Power Generation” Report (2023): An international collaboration (Task 16 of the IEA PVPS program) surveyed and extended many high-penetration renewable case studies. It found a strong consensus that overcapacity plus curtailment is central to cost-optimally transforming intermittent renewables into firm, dispatchable power (IEA PVPS, 2023). For instance, a pan-European simulation found that oversizing wind and PV by roughly 20–30% (with corresponding curtailment of surplus) would greatly alleviate seasonal shortfalls, making it easier for the grid to meet demand even in “wind drought” years or sunless weeks (van Eldik & van Sark, 2023). The same report highlighted an Italian case study aiming for firm 24/365 solar generation: by incrementally overbuilding PV and wind and using batteries, Italy could meet nearly all demand by 2060. One key finding was that curtailment should no longer be viewed as wasteful – rather, “VRE curtailment should not be avoided but promoted if it is proactively managed”. Embracing some curtailment was identified as a “paradigm shift” required to reach 92% renewable share in Italy without major cost penalties (Pierro et al., 2021). In summary, the IEA PVPS research compendium concludes that overbuilding plus curtailment is increasingly acknowledged as a cornerstone strategy for ultra-high renewable grids, providing firm power at lower cost than a zero-curtailment approach.
• Cost-Optimal Curtailment in California (Wang et al., 2021): As noted earlier, Wang et al. analyzed a 100% clean electricity scenario for California by 2045. Their model endogenously optimized the mix of wind, solar, and various storage technologies. The result was a clear endorsement of overbuild: the least-cost solution involved significant oversizing of solar and wind such that roughly 25–43% of potential generation was curtailed annually. This level of overbuild slashed the required storage build-out (especially long-duration storage) and brought down total costs dramatically. Conversely, a scenario forced to use all renewable energy (0% curtailment) saw exorbitant costs due to huge storage investments. The authors note that allowing some oversupply and curtailment cut the cost of decarbonizing California’s grid by a factor of three (Wang et al., 2021).
• Other Studies and Models: The general principle holds across many analyses. Modeling for the U.S. Midcontinent (MISO) region similarly found that a combination of overbuilt PV/wind and storage could meet 100% of electricity demand by 2050 at an average cost around $40/MWh – about the same as today’s fossil-heavy grid (Perez, 2020). In fact, achieving 95% renewable supply was calculated to be even cheaper than current costs, indicating diminishing returns only when approaching the last few percent of replacement for dispatchable plants suggests that pushing from 95% to 100% may incur some cost premium, but that large majority renewables are economically advantageous. Other researchers have pointed out that if a small amount of firm low-carbon capacity (e.g. geothermal, biomass, or gas with carbon capture) is available, it can cover infrequent shortfalls and thereby halve the cost of achieving 100% renewables compared to a purist approach with no thermal backup. However, even in studies that include firm resources, the bulk of energy still comes from overbuilt wind and solar, because they are the cheapest sources – the firm capacity sits idle most of the time and runs only when absolutely needed. The Royal Society in the UK, examining deep decarbonization, likewise recommended on the order of 20–30% renewable overbuild for the UK grid, to ensure reliability during rare weather extremes (Gaster, 2024). Across 37 years of simulated meteorological data, they found occasional “wind drought” seasons; building 30% extra wind/solar and interconnecting with neighboring grids would minimize those deficits. The surplus energy in good years could be used to charge storage or exported, essentially at near-zero marginal cost (Gaster, 2024).
• Similarly, a study by Oxford University's Institute for New Economic Thinking found that renewables offered both the least cost system, and one that would produce more energy than today. Their “Fast Transition” scenario – which resembles RethinkX’s trajectory in aiming for near-total decarbonization by 2050 – would “provide 55% more energy services globally than today” by mid-century. Crucially, they concluded this path would save at least $12 trillion compared to business-as-usual, thanks to learning-curve cost declines. In other words, a win-win-win: more energy, lower cost, and climate stability. The Oxford team emphasised that faster deployment drives faster cost reduction – a virtuous circle: “scaling up key green technologies will continue to drive their costs down – and the faster we go, the more we will save.” (Way et. al, 2022)

Collectively, these studies strongly support RethinkX’s analysis that enormous quantities of clean electricity can be provided affordably by embracing oversupply. The literature validates the concept of a renewable energy “superpower” system (to use RethinkX’s term SWB Superpower) whereby solar and wind capacity well above the yearly average demand is built, ensuring that even during unfavorable periods the system can meet loads with minimal help from storage or backup. When conditions are favorable (sunny/windy), the extra generation simply goes unused or – as RethinkX in particular emphasise – gets diverted into new productive uses – for example, making hydrogen fuel, desalinating water, or charging electric vehicles – which can further improve economic returns. The net result is an energy system characterized by abundance rather than scarcity, with plenty of clean power available at near-zero marginal cost during large portions of the year (Dorr et al., 2025).

Implications and Challenges of Clean Energy Superabundance

If overbuilding renewables is so advantageous technically and economically, one might wonder why it isn’t already standard practice. There are a few important challenges and considerations to address when moving to this new paradigm:

Market Design and Investment Signals

Our current electricity markets are not well-suited to a world of deliberate oversupply. In a heavily overbuilt grid, there will be many hours when electricity is plentiful and effectively free. In the current paradigm, one can expect prolonged periods of zero or negative prices when excess solar or wind is being curtailed. While this is great for consumers and society, it poses a revenue problem for project developers under traditional market structures.

As one analysis noted, “longer periods with zero market revenues make VRE projects much less bankable” in today’s market environment (Gaster, 2024). Investors might be unwilling to finance generation capacity that is expected to be curtailed a significant portion of the time, unless new revenue mechanisms exist (for example, contracts that reward capacity or environmental value rather than only energy delivered).

That’s why RethinkX’s vision of superpower – producing useful surplus electricity harnessed for a vast new range of applications (including, for instance, powering a circular materials economy), is critical to realise the counterintuitive new economic opportunities and models that will emerge from this design. Achieving superabundance may require restructuring market incentives – for instance, paying renewables for available capacity or resiliency services, as well as developing alternative offtake uses for surplus energy (such as green hydrogen production) to monetize the excess.

Fortunately, many regions are already experimenting with such ideas (e.g. Denmark’s planned “energy hubs” to export surplus wind power). As ‘superpower’ is increasingly an emergent feature of renewable energy systems that are already being built (as they are build to meet peak demand during difficult periods, they tend to produce surplus at most other times of the year), it will soon become clear that these new energy systems have created a whole new system possibility space for innovation premised on abundant surplus electricity.

Global Equity and Affordability

Another concern is whether deliberate overbuilding is affordable for lower-income countries or regions where investment capital is scarce. Critics argue that telling developing nations to install 30% more solar panels than they “need” could be a tough sell when budgets are tight (Gaster, 2024). The counterargument, supported by the data above, is that the alternative (trying to avoid curtailment via huge storage or fossil backup) is even more expensive in the long run. Nevertheless, it will be important to ensure financing models (possibly with international support) that enable poorer countries to reap the long-term cost savings of an overbuild approach.

As renewable costs continue to fall, the additional upfront expense of, say, 20% overbuild may be marginal – especially if innovative uses of excess power can generate revenue. Still, policymakers will need to be convinced to plan for “extra” capacity. This may require reframing the conversation: instead of viewing it as wasted investment, emphasize that overbuilding is an insurance policy and a means to foster and power new industries at minimum energy cost (just as maintaining some spare power plant capacity for reliability is standard practice). When presented with the stark choice – expensive overbuild and cheap energy for new industrial innovation vs. even more expensive storage, or else risk blackouts – the politics may shift in favor of overcapacity (Gaster, 2024).

Last 5–10% to 100%

Many studies show that getting to roughly 90–95% renewable electricity can be done at low cost, but achieving a full 100% all the time can sharply increase marginal costs. Overbuilding helps mitigate this by shrinking the gaps, yet extremely rare events (e.g. an unusually sunless, windless week) could still necessitate enormous capacity especially in particular localities if you truly want zero load loss with only wind, solar, and batteries.

In practical terms, some combination of long-duration storage (VLDES), demand flexibility, or a small amount of carbon-neutral fuel backup (like renewable gas or hydrogen turbines) might be used to cover these tail-end events more economically. RethinkX’s vision leans heavily on batteries and oversupply, assuming further improvements in storage cost and performance. The literature suggests this is plausible, especially as battery costs decline, but also indicates diminishing returns beyond a certain overbuild level.

A possible real-world outcome is that grids achieve superabundant cheap energy for 95% of hours, with a few percent of hours handled by either drawing down long-term storage or firing up some form of dispatchable generator (which could be a renewable-fueled gas plant kept for insurance). Notably, even very high renewable scenarios by mid-century often retain a role for existing gas plants as “capacity insurance” – used rarely, but valuable for reliability (Gaster, 2024). Over time, as technology advances, even those rare gaps could be filled by solutions like seasonal storage (e.g. power-to-hydrogen and back) or by simply further oversizing and interconnecting geographically diverse resources.

Infrastructure and Land

Achieving an overbuilt renewable system at scale will require large amounts of solar panels, wind turbines, and associated infrastructure. While the land and material needs are considered manageable in most analyses (especially since solar’s footprint is small relative to its output, and there are vast rooftop/urban spaces for PV), local impacts must be managed. Overbuilding by 30% means 30% more turbines or panels than a minimum scenario – a significant increase, though still far less land-intensive than the status quo of fossil fuel extraction.

Smart planning (such as using already disturbed land, offshore wind, etc.) can minimize environmental footprint even with the higher capacity. Additionally, transmission expansion is often critical to an overbuild strategy: moving surplus energy from where the wind is blowing to where it’s needed. Strong grid interconnections effectively allow regions to share overcapacity, reducing the total overbuild required. Studies find that a well-connected grid can lower the cost of variability management by spreading resource diversity (Gaster, 2024). Hence, investment in transmission and grid flexibility complements the overbuilding approach.

In sum, none of these challenges are insurmountable – they represent evolutionary changes in policy and grid operation that can accompany the revolutionary drop in renewable energy costs. Historical precedent exists: electric systems have long maintained reserve margins (excess capacity) for reliability; the difference now is merely one of degree and purpose. With appropriate market reforms, support mechanisms, and sector coupling (using surplus power in other economic sectors), the transition to an overbuilt renewable paradigm can be managed to benefit all stakeholders.

Conclusion

The scientific literature reviewed above provides strong evidence that the core premise of RethinkX’s Stellar Energy analysis – the viability and desirability of overbuilding renewables to achieve clean energy superabundance – is well-founded. Across modeling studies and real-world scenarios, the same message echoes: a certain level of oversupply and curtailment is not only viable but in fact optimal to meet demand at lowest cost. By leveraging the ultra-low cost of modern solar and wind technology, we can afford to install more capacity than needed and thereby ensure reliability even in unfavorable conditions, without massive expenditures on storage or backup fuel. This strategy turns the old logic of “minimize waste” on its head, heralding a new paradigm where excess green energy is a feature, not a bug – an abundant resource to be harnessed or simply spilled with minimal regret.

All told, the literature supports a future where electricity is superabundant and cheap, enabling profound economic and social benefits. RethinkX’s vision of near-zero marginal cost clean energy – available to drive new industries and uplift global living standards – is not a fanciful utopia but increasingly a realistic projection grounded in data (Dorr et al., 2025).

Achieving this future will require proactive policy and planning: retooling market structures, investing in grids and storage, and overcoming ingrained biases against curtailment. Yet the reward is enormous. This is the first time in human history that overbuilding infrastructure makes economic sense – a transformative opportunity to accelerate the transition to 100% renewable energy on a sound economic footing (ASES, 2023). Embracing clean energy superabundance via strategic overbuilding could indeed mark the planetary phase shift that RethinkX describes, launching us into an era where energy is clean, plentiful, and empowering for all.

References

American Solar Energy Society (ASES). (2023, March 4). Feasibility and Requirements of a 100% Transition to Renewable Energy (Firm Power Generation 2023). https://ases.org/firm-power-generation/

Dorr, A., Arbib, J., & Seba, T. (2025). Understanding Stellar Energy: How SWB Superpower will create clean energy superabundance.  https://www.rethinkx.com/publications/understandingstellarenergy2025.en

Gaster, R. (2024). Why Wind and Solar Need Natural Gas: A Realistic Approach to Variability. ITIF Report https://itif.org/publications/2024/09/30/why-wind-and-solar-need-natural-gas-realistic-approach-to-variability/

IEA PVPS Task 16. (2023). Firm Power Generation: IEA PVPS T16-04:2023 Report. International Energy Agency Photovoltaic Power Systems Programme. https://iea-pvps.org/wp-content/uploads/2023/01/Report-IEA-PVPS-T16-04-2023-Firm-Power-generation.pdf

Perez, M., Perez, R., Rábago, K. R., & Putnam, M. (2019). Overbuilding & curtailment: The cost-effective enablers of firm PV generation. Solar Energy, 180, 412–422. https://doi.org/10.1016/j.solener.2018.12.074

Pierro, M., Perez, R., Perez, M., Prina, M. G., Moser, D., & Cornaro, C. (2021). From solar imbalance regulation to firm 24/365 solar generation: An Italian protocol for massive solar integration. Renewable Energy, 169, 425–436. https://doi.org/10.1016/j.renene.2021.01.025

Wang, S., Tarroja, B., Schell, L. S., & Samuelsen, S. (2021). Determining cost-optimal approaches for managing excess renewable electricity in decarbonized electricity systems. Renewable Energy, 178, 1187–1197. https://doi.org/10.1016/j.renene.2021.06.093

Way et al., (2022) Empirically grounded technology forecasts and the energy transition. Joule, 6, 9, 2057-2082,
https://doi.org/10.1016/j.joule.2022.08.009