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"[Errno 13] Permission denied: '/home/micro/.marchwarden/costs.jsonl'", "event": "cost_ledger_write_failed", "researcher": "web", "trace_id": "e3fa81c3-eaff-4f76-9b50-d61e70e54540", "logger": "marchwarden.researcher.web", "level": "warning", "timestamp": "2026-04-09T02:02:55.648701Z"} {"event": "Processing request of type ListToolsRequest", "logger": "mcp.server.lowlevel.server", "level": "info", "timestamp": "2026-04-09T02:02:55.654584Z"} {"trace_id": "e3fa81c3-eaff-4f76-9b50-d61e70e54540", "confidence": 0.88, "citations": 10, "tokens_used": 48230, "wall_time_sec": 95.80813455581665, "event": "ask_completed", "logger": "marchwarden.cli", "level": "info", "timestamp": "2026-04-09T02:02:55.883067Z"} ╭─────────────────────────────────── Answer ───────────────────────────────────╮ │ Wind and solar capacity factors in the continental United States differ │ │ notably, with wind generally outperforming utility-scale solar on an annual │ │ average basis, though both vary significantly by location and season. │ │ │ │ **Wind Capacity Factors:** In 2023, the U.S. wind turbine fleet had an │ │ average capacity factor of 33.5%, which was an eight-year low driven by │ │ weaker-than-normal wind speeds (down from the 2022 all-time high of 35.9%). │ │ Wind capacity factors are highest in spring (March–April) and lowest in │ │ summer. In April 2024, wind generation hit a record 47.7 TWh, exceeding coal │ │ generation for the second consecutive month. The NREL wind resource │ │ assessment identifies areas with capacity factors ≥30% (generally mean │ │ annual wind speeds ≥6.4 m/s) as suitable for development, with the │ │ highest-potential zones in the central Great Plains. The U.S. total │ │ installed wind capacity reached ~150,500 MW by end of 2023. │ │ │ │ **Solar (Utility-Scale PV) Capacity Factors:** The weighted average U.S. │ │ utility-scale solar capacity factor was 23.5% in 2023, down 0.7 percentage │ │ points from 24.2% in 2022. NREL's Annual Technology Baseline categorizes │ │ utility-scale PV capacity factors into 10 resource classes based on mean │ │ global horizontal irradiance (GHI); the desert Southwest achieves the │ │ highest factors, while northern states achieve at least ~70% of the │ │ Southwest's value. Solar generation is highest in summer and lowest in │ │ winter, opposite to wind seasonality. │ │ │ │ **Comparison Summary:** On an annual fleet-wide average, wind capacity │ │ factors (~33–36%) are materially higher than utility-scale solar capacity │ │ factors (~23–24%). However, the two resources are complementary seasonally: │ │ wind peaks in spring, solar peaks in summer. Both are intermittent │ │ resources. In 2025, wind and solar together generated a record 17% of U.S. │ │ electricity (wind: 464,000 GWh; utility-scale solar: 296,000 GWh), │ │ reflecting wind's larger current installed base despite solar's faster │ │ recent capacity growth. │ ╰──────────────────────────────────────────────────────────────────────────────╯ Citations ┏━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━┓ ┃ # ┃ Title / Locator ┃ Excerpt ┃ Conf ┃ ┡━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━┩ │ 1 │ Wind generation declined in │ Last year, the average │ 0.98 │ │ │ 2023 for the first time since │ utilization rate, or capacity │ │ │ │ the 1990s - EIA │ factor, of the wind turbine │ │ │ │ https://www.eia.gov/todayinen │ fleet fell to an eight-year │ │ │ │ ergy/detail.php?id=61943 │ low of 33.5% (compared with │ │ │ │ │ 35.9% in 2022, the all-time │ │ │ │ │ high). │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 2 │ US solar capacity factors │ The weighted average US solar │ 0.95 │ │ │ retreat in 2023, break │ capacity factor came in at a │ │ │ │ multiyear streak above 24% │ calculated 23.5% annually in │ │ │ │ https://www.spglobal.com/mark │ 2023, down 0.7 percentage │ │ │ │ et-intelligence/en/news-insig │ point from 24.2% in 2022. │ │ │ │ hts/research/us-solar-capacit │ │ │ │ │ y-factors-retreat-in-2023-bre │ │ │ │ │ ak-multiyear-streak-above-24p │ │ │ │ │ erc │ │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 3 │ U.S. wind generation hit │ Wind generation, meanwhile, │ 0.97 │ │ │ record in April 2024, │ increased to a record 47.7 │ │ │ │ exceeding coal-fired │ TWh. However, during the first │ │ │ │ generation - EIA │ four months of 2024, │ │ │ │ https://www.eia.gov/todayinen │ coal-fired generation was 15% │ │ │ │ ergy/detail.php?id=62784 │ higher than wind generation in │ │ │ │ │ the United States. Installed │ │ │ │ │ wind power generating capacity │ │ │ │ │ has increased substantially in │ │ │ │ │ the United States over the │ │ │ │ │ last 25 years, growing from │ │ │ │ │ 2.4 gigawatts (GW) in 2000 to │ │ │ │ │ 150.1 GW in April 2024. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 4 │ Land-Based Wind Market Report │ The U.S. wind industry │ 0.97 │ │ │ 2024: Edition | Department of │ installed 6,474 megawatts (MW) │ │ │ │ Energy │ of new land-based wind │ │ │ │ https://www.energy.gov/cmei/s │ capacity in 2023, bringing the │ │ │ │ ystems/land-based-wind-market │ cumulative total to nearly │ │ │ │ -report-2024-edition │ 150,500 MW. Also, $10.8 │ │ │ │ │ billion was invested in 2023 │ │ │ │ │ in land-based wind energy │ │ │ │ │ expansion. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 5 │ Utility-Scale PV | │ The 2024 ATB provides the │ 0.93 │ │ │ Electricity | 2024 | ATB | │ average capacity factor for 10 │ │ │ │ NREL │ resource categories in the │ │ │ │ https://atb.nrel.gov/electric │ United States, binned by mean │ │ │ │ ity/2024/utility-scale_pv │ GHI. Average capacity factors │ │ │ │ │ are calculated using │ │ │ │ │ county-level capacity factor │ │ │ │ │ averages from the Renewable │ │ │ │ │ Energy Potential (reV) model │ │ │ │ │ for 1998–2021. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 6 │ NREL projects solar │ In the latest update, zones │ 0.85 │ │ │ generation and costs for 10 │ 2-8, representing all but the │ │ │ │ U.S. zones – pv magazine USA │ northernmost states in the │ │ │ │ https://pv-magazine-usa.com/2 │ continental U.S., solar │ │ │ │ 021/07/22/nrel-projects-solar │ installations have a capacity │ │ │ │ -generation-and-costs-for-10- │ factor that is at least 70% of │ │ │ │ u-s-zones/ │ that in the desert Southwest's │ │ │ │ │ zone 1, the data show. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 7 │ Wind and solar generated a │ In 2025, wind power generated │ 0.96 │ │ │ record 17% of U.S. │ 464,000 GWh of electricity, 3% │ │ │ │ electricity in 2025 - EIA │ more than in 2024. In 2025, │ │ │ │ https://www.eia.gov/todayinen │ utility-scale solar power │ │ │ │ ergy/detail.php?id=67367 │ generation totaled 296,000 │ │ │ │ │ GWh, 34% more than in 2024. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 8 │ 80 and 100 Meter Wind Energy │ Windy land defined as areas │ 0.82 │ │ │ Resource Potential for the │ with >= 30% CF*, generally │ │ │ │ United States - NREL │ mean annual wind speeds >= 6.4 │ │ │ │ https://docs.nrel.gov/docs/fy │ m/s... U.S. wind potential │ │ │ │ 10osti/48036.pdf │ from areas with CF*>=30% is │ │ │ │ │ enormous, with almost 10,500 │ │ │ │ │ GW capacity at 80 m and 12,000 │ │ │ │ │ GW capacity at 100 m. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 9 │ Wind power in the United │ In 2025, 464.4 terawatt-hours │ 0.88 │ │ │ States - Wikipedia │ were generated by wind power, │ │ │ │ https://en.wikipedia.org/wiki │ or 10.48% of electricity in │ │ │ │ /Wind_power_in_the_United_Sta │ the United States. In March │ │ │ │ tes │ and April of 2024, electricity │ │ │ │ │ generation from wind exceeded │ │ │ │ │ generation from coal, once the │ │ │ │ │ dominant source of U.S. │ │ │ │ │ electricity, for an extended │ │ │ │ │ period for the first time. │ │ ├─────┼───────────────────────────────┼────────────────────────────────┼───────┤ │ 10 │ Utility-scale U.S. solar │ In August 2024, a total of │ 0.94 │ │ │ electricity generation │ 107.4 gigawatts (GW) of solar │ │ │ │ continues to grow in 2024 - │ electricity generating │ │ │ │ EIA │ capacity was operating in the │ │ │ │ https://www.eia.gov/todayinen │ Lower 48 states compared with │ │ │ │ ergy/detail.php?id=63324 │ 81.9 GW in August 2023... In │ │ │ │ │ the final five months of 2024, │ │ │ │ │ we expect new U.S. solar │ │ │ │ │ electricity generating │ │ │ │ │ capacity will make up 63%, or │ │ │ │ │ nearly two-thirds, of all new │ │ │ │ │ electricity generating │ │ │ │ │ capacity to come online. │ │ └─────┴───────────────────────────────┴────────────────────────────────┴───────┘ Gaps ┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ Category ┃ Topic ┃ Detail ┃ ┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩ │ scope_exceeded │ Offshore wind capacity │ The evidence gathered │ │ │ factors │ focuses on land-based wind. │ │ │ │ Offshore wind typically has │ │ │ │ higher capacity factors │ │ │ │ (40–50%+) than land-based │ │ │ │ wind but was not the │ │ │ │ primary focus of the │ │ │ │ sources retrieved. │ ├──────────────────┼─────────────────────────────┼─────────────────────────────┤ │ source_not_found │ Most recent 2024 annual │ The 2023 annual wind │ │ │ average wind capacity │ capacity factor (33.5%) is │ │ │ factor │ confirmed, but a final 2024 │ │ │ │ annual figure was not found │ │ │ │ in the sources; only │ │ │ │ monthly records for April │ │ │ │ 2024 were available. │ ├──────────────────┼─────────────────────────────┼─────────────────────────────┤ │ source_not_found │ Regional breakdown of wind │ State- or region-level │ │ │ vs. solar capacity factors │ direct comparisons of wind │ │ │ within the continental U.S. │ vs. solar capacity factors │ │ │ │ within the continental U.S. │ │ │ │ were not available in the │ │ │ │ retrieved sources. │ ├──────────────────┼─────────────────────────────┼─────────────────────────────┤ │ scope_exceeded │ Small-scale/rooftop solar │ The 23.5% solar capacity │ │ │ capacity factors │ factor applies to │ │ │ │ utility-scale solar. │ │ │ │ Distributed/rooftop solar │ │ │ │ typically has lower │ │ │ │ capacity factors due to │ │ │ │ suboptimal orientation; │ │ │ │ this was not quantified in │ │ │ │ the retrieved evidence. │ └──────────────────┴─────────────────────────────┴─────────────────────────────┘ Discovery Events ┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓ ┃ ┃ Suggested ┃ ┃ ┃ ┃ Type ┃ Researcher ┃ Query ┃ Reason ┃ ┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩ │ related_research │ database │ U.S. offshore │ Offshore wind has │ │ │ │ wind capacity │ substantially │ │ │ │ factors 2023 2024 │ higher capacity │ │ │ │ compared to │ factors than │ │ │ │ land-based wind │ land-based wind │ │ │ │ and solar │ and solar, which │ │ │ │ │ would complete │ │ │ │ │ the renewable │ │ │ │ │ capacity factor │ │ │ │ │ comparison │ │ │ │ │ picture. │ ├──────────────────┼───────────────────┼───────────────────┼───────────────────┤ │ related_research │ database │ NREL ATB 2024 │ NREL ATB provides │ │ │ │ utility-scale │ wind capacity │ │ │ │ wind capacity │ factors by │ │ │ │ factor by │ resource class │ │ │ │ resource class │ similar to solar, │ │ │ │ continental US │ enabling direct │ │ │ │ │ apples-to-apples │ │ │ │ │ regional │ │ │ │ │ comparison with │ │ │ │ │ solar CF data. │ ├──────────────────┼───────────────────┼───────────────────┼───────────────────┤ │ related_research │ database │ seasonal wind vs │ Wind peaks in │ │ │ │ solar capacity │ spring, solar in │ │ │ │ factor │ summer—understand │ │ │ │ complementarity │ ing this │ │ │ │ United States │ complementarity │ │ │ │ grid balancing │ is critical for │ │ │ │ │ grid planning and │ │ │ │ │ storage │ │ │ │ │ requirements. │ ├──────────────────┼───────────────────┼───────────────────┼───────────────────┤ │ new_source │ database │ EIA Electric │ The 2024 │ │ │ │ Power Monthly │ full-year wind │ │ │ │ 2024 annual wind │ capacity factor │ │ │ │ capacity factor │ would allow │ │ │ │ final │ updated │ │ │ │ │ comparison with │ │ │ │ │ the 2023 solar │ │ │ │ │ capacity factor │ │ │ │ │ of 23.5%. │ └──────────────────┴───────────────────┴───────────────────┴───────────────────┘ Open Questions ┏━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ Priority ┃ Question ┃ Context ┃ ┡━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩ │ high │ How do wind and solar capacity │ Texas led wind capacity │ │ │ factors compare on a regional │ additions in 2023 (1,323 MW) │ │ │ basis within the continental │ and is the second-largest │ │ │ U.S., particularly in states │ utility-scale solar state (18.8 │ │ │ like Texas and California that │ GW). California leads solar. │ │ │ have significant installations │ Regional comparisons would │ │ │ of both? │ clarify where each resource is │ │ │ │ most competitive. │ ├──────────┼─────────────────────────────────┼─────────────────────────────────┤ │ high │ What is the projected │ NREL's ATB provides │ │ │ trajectory of utility-scale │ Advanced/Moderate/Conservative │ │ │ solar capacity factors as │ scenarios for solar CF │ │ │ technology improves, and will │ improvements through 2050, and │ │ │ solar eventually close the gap │ solar capacity additions are │ │ │ with wind on a fleet-wide │ now outpacing wind. The │ │ │ average basis? │ convergence timeline is │ │ │ │ unclear. │ ├──────────┼─────────────────────────────────┼─────────────────────────────────┤ │ medium │ How did the 2023 wind │ Wind generation fell 2.1% in │ │ │ generation decline (due to low │ 2023 to an eight-year-low │ │ │ wind speeds) affect investment │ capacity factor of 33.5%, while │ │ │ decisions for new wind vs. │ solar continued growing. This │ │ │ solar projects? │ may have influenced utility │ │ │ │ procurement decisions. │ ├──────────┼─────────────────────────────────┼─────────────────────────────────┤ │ medium │ What is the capacity factor of │ The DOE Wind Market Reports │ │ │ offshore wind installations in │ cover offshore wind separately, │ │ │ the U.S., and how does it │ and offshore wind typically │ │ │ compare to both land-based wind │ achieves materially higher │ │ │ and utility-scale solar? │ capacity factors than │ │ │ │ land-based wind (~40–50%), but │ │ │ │ this was not quantified in the │ │ │ │ retrieved sources. │ ├──────────┼─────────────────────────────────┼─────────────────────────────────┤ │ low │ How does the Inflation │ The IRA led to significant │ │ │ Reduction Act's impact on wind │ near-term wind deployment │ │ │ and solar deployment affect │ forecast increases and billions │ │ │ future capacity factor trends, │ in domestic supply chain │ │ │ given that larger, more │ investment. Average wind │ │ │ efficient turbines and │ turbine capacity grew to 3.4 MW │ │ │ better-sited projects may │ in 2023, up 375% since │ │ │ improve wind CFs? │ 1998–1999. │ └──────────┴─────────────────────────────────┴─────────────────────────────────┘ ╭───────────────────────────────── Confidence ─────────────────────────────────╮ │ Overall: 0.88 │ │ Corroborating sources: 10 │ │ Source authority: high │ │ Contradiction detected: False │ │ Query specificity match: 0.85 │ │ Budget status: spent │ │ Recency: current │ ╰──────────────────────────────────────────────────────────────────────────────╯ ╭──────────────────────────────────── Cost ────────────────────────────────────╮ │ Tokens: 48230 │ │ Iterations: 3 │ │ Wall time: 95.81s │ │ Model: claude-sonnet-4-6 │ ╰──────────────────────────────────────────────────────────────────────────────╯ trace_id: e3fa81c3-eaff-4f76-9b50-d61e70e54540