Blog

Articles about solar energy, PV forecasting, and solar physics

Too Much Sun? Curtailment, Negative Prices, and Your Summer Surplus

Too much sun in summer? Clipping, curtailment, negative prices, and how to turn your midday surplus into real savings.

June 16, 2026

Why Your Solar Panels Produce Less on the Hottest Days

Heat is the enemy of solar output. Here is the physics of temperature derating, and why a cool spring day can beat a scorching one in July.

Jun 9, 2026 · 3 min read

Why New Installations Don't Need Training Data With Physics-Based Models

Most forecast tools need months of history before they work. Physics-based forecasting works from day one. Here's why — and what that means for new PV owners.

May 26, 2026 · 5 min read

Nowcasting vs Day-Ahead vs Weekly — Accuracy at Every Time Horizon

A 15-minute forecast and a 7-day forecast are fundamentally different problems. Here's what each time horizon can realistically deliver and where accuracy breaks down.

May 19, 2026 · 5 min read

Transposition Models: How Volcast Calculates What Hits Your Tilted Panel

Weather data tells us what reaches a horizontal surface. Your panels are tilted. The mathematical bridge between the two is called transposition — and the choice of model matters.

May 12, 2026 · 5 min read

The Irradiance Journey: From Space to Your Solar Panel in 8 Steps

Follow a beam of sunlight from the edge of Earth's atmosphere through scattering, absorption, clouds, and reflection until it reaches your tilted panel and becomes electricity.

May 5, 2026 · 5 min read

Why Cloud Cover Is the Hardest Variable in Solar Prediction

Temperature is predictable. Sun position is calculable. But clouds? Clouds are chaos theory in action — and the single biggest source of solar forecast error.

Apr 28, 2026 · 5 min read

Where Weather Forecasts Come From: NWP Models Explained for PV Owners

Your solar forecast is only as good as its weather input. Here's how numerical weather prediction models work, what they get right, and where they fall short for solar energy.

Apr 21, 2026 · 5 min read

Physics-Based vs ML-Based Solar Forecasting — Why the Approach Matters

Two fundamentally different approaches to predicting solar production. One models the physics, the other learns from data. Here's why the distinction matters for your forecast.

Apr 14, 2026 · 6 min read

What Tilt and Azimuth Actually Do to Your Annual Yield

Two angles define how much energy your solar panels capture. Learn why they matter and why real-world results are more forgiving than you'd think.

Apr 7, 2026 · 4 min read

Direct vs Diffuse Sunlight — Why Cloudy Days Still Generate Power

Not all solar radiation is the same. Understanding the three components of sunlight explains why overcast days still produce electricity.

Mar 31, 2026 · 4 min read

How Solar Panels Actually Convert Sunlight to Electricity

A clear, jargon-free explanation of the photovoltaic effect — from photons hitting silicon to usable AC power in your home.

Mar 24, 2026 · 4 min read

The Three Numbers That Define Your PV Setup (And Why Volcast Only Needs Them)

Tilt, azimuth, and rated power — these three parameters are all a physics-based forecast needs to predict your solar production.

Mar 24, 2026 · 5 min read

Why Your Solar Panels Produce More in Spring Than Summer

The temperature coefficient explained — why cooler sunny days in March and April often outperform the scorching heat of July and August.

Mar 24, 2026 · 4 min read