Written by: Olivier Lam, Physical AI Team, Jua.ai AG
Key Takeaways for European Power Traders
- European wind and solar now exceed 30% of electricity output, which creates correlated imbalance exposure that traditional 2–4× daily NWP updates cannot resolve fast enough.
- EPT-2 outperforms ECMWF HRES on every lead time (0–240 h) for 10 m wind, 100 m wind, 2 m temperature, and surface solar radiation; EPT-2e beats the 50-member ECMWF ENS mean on both RMSE and CRPS.
- Jua for Energy delivers up to 24 updates per day, 15-minute actual-generation refreshes, and ~5 km native resolution over Europe, at a fraction of the cost of HPC-based NWP.
- Forecast accuracy gains translate directly to P&L: a 1 GW wind portfolio can save ~€1.5 M/year and a 1 GW solar portfolio ~€3 M/year with a four-percentage-point accuracy improvement.
- Run live benchmarks on your region before the next market move.
How Europe’s Wind & Solar Mix Drives Correlated Risk
Europe closed 2025 with 304 GW of installed wind capacity — 265 GW onshore and 39 GW offshore. WindEurope projects that figure will reach 439 GW by 2030, with 151 GW of new additions between 2026 and 2030 alone. Combined with utility-scale solar, wind and solar generation already exceed 30% of continental electricity supply, and several countries now source at least 30% of national demand from wind.
This buildout creates a structural forecasting problem for traders. Research into renewable energy forecast errors indicates that wind and solar forecast errors can become uncorrelated at larger site separations for intraday to two-days-ahead lead times, where spatial aggregation smooths individual site errors at day-ahead horizons. However, below those geographic and temporal scales, errors remain correlated and directional. A single poorly resolved frontal system can mis-forecast output across Germany, the Netherlands, and northern France at the same time. The result is correlated imbalance exposure across the very markets where intraday liquidity is deepest, which current workflows struggle to manage in real time.
Why Traditional Day-Ahead Workflows Fall Behind
The standard workflow on a European power desk begins before 7 a.m. A trader downloads overnight ECMWF and GFS runs as raw grib files (the binary format in which numerical weather prediction, or NWP, models distribute gridded atmospheric data), processes them through an in-house pipeline, consults an internal meteorology team or a consultancy, and then stitches together a coherent view of the day from spreadsheets, terminal screens, and vendor dashboards. By the time that view exists, the market has usually priced the consensus.
NWP, which decomposes the atmosphere into three-dimensional grid cells and solves differential equations inside each one, runs at most four times per 24 hours on the supercomputers that power ECMWF and NOAA. Between those runs, numbers are stale. When a model revises its output mid-cycle, the trader typically notices because someone else has already traded on it. In Europe’s weather-driven energy markets, traders now turn to AI and machine-learning tools designed to forecast the forecast itself. These tools anticipate revisions in the ECMWF two-week outlook before those revisions reprice the market.
Several metrics matter when evaluating forecast quality. RMSE (root mean square error) measures the average magnitude of forecast deviation from observed values. CRPS (continuous ranked probability score) measures probabilistic forecast skill and rewards both accuracy and calibrated uncertainty. Ensemble forecasts, which are sets of multiple model runs initialized with slightly perturbed conditions, quantify uncertainty around a central forecast. Lead time is the number of hours between forecast issuance and the valid time being predicted. These concepts frame the benchmark comparison below.
Live Model Benchmarks: EPT-2 vs ECMWF HRES, ENS, Aurora, and GraphCast
The relationship between Jua and Jua for Energy mirrors the relationship between Anthropic and Claude Code: a foundation model and agent company with a flagship vertical product. EPT-2 and EPT-2e are documented in the peer-reviewed technical report arXiv:2507.09703. Every benchmark claim in the table below comes directly from that report.
| Capability | EPT-2 / EPT-2e (Jua for Energy) | ECMWF HRES / ENS | Aurora / GraphCast |
|---|---|---|---|
| Deterministic accuracy (0–240 h, 10 m wind, 100 m wind, 2 m temp, SSRD) | EPT-2 beats HRES on every lead time across all four variables | ECMWF HRES: the 40-year benchmark for deterministic NWP | Aurora loses to EPT-2 on 10 m and 100 m wind across full range; Aurora has no SSRD output |
| Ensemble / probabilistic forecasting | EPT-2e beats the 50-member ECMWF ENS mean on RMSE and CRPS at virtually every lead time | ECMWF ENS: 50-member gold standard for probabilistic NWP | No productised ensemble equivalent from Aurora or GraphCast |
| Update frequency | Up to 24×/day (EPT-2 RR); EPT-2e updates 4×/day; actual-generation power forecasts refresh every 15 minutes | 2–4×/day on HPC supercomputer | Typically 4×/day in research mode; no productised operational schedule |
| Inference cost per simulation | ~0.25 kWh, ~$0.20–$15 on a single GPU, in minutes | ~8,400 kWh, €1,000–€20,000 on HPC, 1–2 hours | Similar order of magnitude to EPT-2 for inference |
EPT-2 is trained on 5+ petabytes of observational data from 120+ sources and benchmarked against more than 10,000 real ground stations on open-source StationBench, with no post-processing or station fine-tuning. That training scale enables a native spatial resolution of ~5 km over Europe, compared with the ~25 km resolution at which Aurora and most AI peers are published. The resolution advantage compounds over time because EPT-2 forecasts at native any-Δt and does not use the fixed 6-hour roll-forward step that causes competing models to accumulate error at longer lead times.
Run EPT-2 head-to-head against your current provider on your own region and variable.
Country-Level Trading Examples: Germany, Great Britain, France
Jua for Energy delivers live power forecasts for solar, wind onshore, wind offshore, total wind, total renewables, load, and residual load across Germany, Great Britain, France, the Netherlands, and Belgium. Two complementary models run on the same surface. A Fundamental Model combines EPT weather forecasts with installed-capacity data and runs out to 20 days. An Actual Generation Model refreshes every 15 minutes with a 48-hour horizon and lower near-term error.
Germany installed over 5 GW of new wind capacity in 2025, which brings its total to a scale where a single poorly resolved frontal passage can shift generation by several gigawatts within an hour. Divergence alerts on the Jua platform fire the moment EPT-2 and ECMWF ENS disagree on 100 m wind over northern Germany. The trade window opens with a notification, not a missed move.
Great Britain sourced 29.7% of its electricity from wind in 2025. Intraday imbalance pricing in the GB market is particularly sensitive to offshore wind ramps in the North Sea. Correction alerts on Jua for Energy fire the moment a model revises its own output between runs, which gives traders a chance to react before the market reprices.
France combines significant nuclear baseload with growing solar capacity, which makes residual load forecasting, the net demand after renewables, the critical variable for day-ahead positioning. Jua for Energy’s Fundamental Model runs residual load forecasts, with full cross-model comparison, deltas, and disagreement heatmaps available in the same workspace.
Price Impact and Programmatic Access
Forecast accuracy translates directly to P&L. Jua’s forecasts carry an estimated $1.5 million P&L impact per gigawatt annually in European energy markets. In the market-sizing terms Jua uses for procurement conversations, a 1 GW wind portfolio that gains four percentage points of forecast accuracy saves approximately €1.5 M per year under typical hedging and imbalance-penalty structures. A 1 GW solar portfolio at the same accuracy gain saves approximately €3 M per year. Multi-GW portfolios scale these economics linearly.
Programmatic access starts with a single command: pip install jua. That command unlocks a REST API exposing 25+ models, including 10 proprietary AI models from the EPT family and 15 third-party NWP and AI models such as ECMWF HRES, ENS, AIFS, NOAA GFS, DWD ICON, Microsoft Aurora, and GFS GraphCast, through a unified schema with Apache Arrow support for large payloads. The same API integrates ENTSO-E grid data directly, which gives traders actual-generation and capacity figures alongside forecast data in a single call. Hindcast data across multiple Jua and third-party models is also available through the API, which enables backtests of systematic strategies without stitching together multiple vendor feeds.
Athena, Jua’s AI agent instrumented with the Jua for Energy tool surface, answers natural-language queries such as “what is the 100 m wind forecast spread across models for northern Germany tonight?” and returns a briefing, a benchmark, or a custom widget in approximately 90 seconds. Athena turns raw physics predictions from EPT-2 into actionable trading context by reading market conditions and modeling forecast divergence. Trading houses and quant desks describe Athena as another headcount, for free.
See Athena generate a live briefing on your market in under 90 seconds.
Frequently Asked Questions
How accurate are current Europe wind and solar forecasts?
Accuracy varies significantly by model, lead time, and region. Traditional NWP models such as ECMWF HRES set the benchmark for deterministic forecasting and have done so for 40 years. Wind and solar forecast errors can become uncorrelated at larger site separations for intraday to two-days-ahead lead times, which means errors at individual sites are not always smoothed away by portfolio aggregation. As documented in the benchmark comparison above, EPT-2 consistently outperforms ECMWF HRES across all lead times on the variables that drive energy P&L. The ensemble variant, EPT-2e, also outperforms the ECMWF ENS mean on both RMSE and CRPS at virtually every lead time, with results documented in arXiv:2507.09703 and validated against more than 10,000 real ground stations with no post-processing.
What is the difference between NWP and foundation-model forecasts?
Numerical weather prediction decomposes the atmosphere into three-dimensional grid cells and solves differential equations inside each one. It is physically rigorous and has been the industry standard for decades. Its constraint is compute: a single NWP simulation consumes approximately 8,400 kWh and costs €1,000–€20,000 on HPC infrastructure, which limits global runs to two to four per day. EPT, the Earth Physics Transformer, is a general spatiotemporal foundation model that learns the governing physics of complex systems directly from observational data, in a latent representation integrated forward in time faster than the physics itself unfolds. A single EPT-2 inference runs on a single GPU in minutes at approximately 0.25 kWh and $0.20–$15. The cost asymmetry is roughly four orders of magnitude, so EPT-2 RR can update up to 24 times per day where traditional NWP updates two to four times. EPT outputs are physically constrained by construction because the model learns conservation laws from data rather than applying them symbolically, which prevents the kind of hallucinations seen when a generic transformer is applied naively to physics.
Can Jua for Energy replace my ECMWF subscription?
Jua for Energy does not replace ECMWF for most customers. Most serious users keep their ECMWF subscription and run Jua for Energy alongside it. ECMWF AIFS, ECMWF’s own AI model, runs natively on the Jua platform in the same workspace as EPT-2 and EPT-2e. Jua for Energy instead displaces the plumbing around the ECMWF feed, including the in-house grib pipeline, the manual benchmarking harness, the morning-briefing analyst, and the dashboard stitching across a dozen vendor screens. The 7–9 a.m. manual prep routine compresses into a single workspace, refreshed up to 24 times a day, where every model, including ECMWF, GFS, AIFS, Aurora, and EPT, appears on the same screen with one schema and one API.
How fast can I run a live benchmark on my region?
A live benchmark on the Jua platform returns results in seconds from first selection. A prospect picks a region and a variable that matters to their book, selects their current provider alongside EPT-2 or EPT-2e, and the platform returns a head-to-head accuracy comparison immediately. Backtests against years of historical forecasts run in approximately 5 minutes via Athena, or directly through the Python SDK for teams that prefer programmatic access. This workflow usually triggers deals for Jua customers because meteorologists who were sceptical of vendor accuracy claims become internal champions the moment they run the benchmark themselves.
Conclusion: Move Before the Market Reprices
Europe’s wind and solar buildout continues to accelerate. WindEurope projects 151 GW of new wind capacity between 2026 and 2030, with renewable electricity generation across the continent rising 60% by the end of the decade. Every gigawatt added increases the sensitivity of intraday prices to forecast error and raises the cost of relying on a stack that updates four times a day and requires two hours of manual assembly before it is tradeable.
Jua is a foundation model and agent company, and Jua for Energy is its first applied product. EPT-2 is the global state of the art in atmospheric prediction, outperforming ECMWF HRES, Microsoft Aurora, and Google DeepMind GraphCast across the lead times and variables that drive energy P&L. EPT-2e outperforms the industry-standard 50-member ensemble on both accuracy metrics at virtually every lead time. Athena resolves natural-language queries into briefings, benchmarks, and backtests in approximately 90 seconds. The platform’s rapid refresh cycle fires divergence and correction alerts the moment models disagree or revise and exposes every model through a single API with pip install jua.
Customers including Axpo, TotalEnergies, Statkraft, EnBW, EDF, and Hydro-Québec already execute daily trading decisions on the platform. The live benchmark is available now, on your region, on your variable, against your current provider.
See EPT-2 benchmarked against your current provider before the next model run lands.
