How to scale yield forecasting when your PV portfolio is growing?

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June 30, 2025

As the commercial and industrial (C&I) solar sector matures, developers and asset managers are facing a new challenge: scale.

Managing a handful of PV sites is one thing. But managing 30, 100, or even 300 distributed sites across geographies? That’s a different game entirely, especially when it comes to forecasting long-term energy yield.

Traditional methods for Long-Term Yield Assessments (LTYAs) were never designed for this scale. They are manual, slow, expensive, and often provide incomplete or misleading insights when extrapolated across portfolios.

That’s why 3E built Mass LTYA: a scalable, automated and high-precision approach to yield forecasting, purpose-built for large PV portfolios.

Why traditional LTYA methods break down in large portfolios

If you're a solar developer or asset manager, you already know that accurate long-term yield forecasts are essential for:

• Securing financing and ensuring bankability

• Modelling revenue and ROI

• Assessing and managing risk

• Optimising asset performance

But here is where traditional approaches fall short:

Why traditional yield assessment methods fall short at scale.

The more assets you have, the harder and more expensive it gets to generate actionable insights across the board.

Introducing Mass LTYA: a digital twin-driven breakthrough

3E’s Mass LTYA changes the game by combining 25+ years of high-resolution irradiance data, cutting-edge data science, with SynaptiQ, our asset management performance SaaS digital twin platform.

Instead of modelling a few ‘representative’ sites, you simulate every single asset, quickly, consistently and accurately.

Here’s what makes it different:

• 100% asset coverage: simulate all assets in your portfolio, not just a sample, and generate P50/P90 profiles with confidence.

• Digital twin technology: each site is modelled as a digital twin within SynaptiQ, ensuring high fidelity to real-world configuration.

• Loss breakdown analysis: understand what’s driving yield with detailed breakdowns by soiling, shading, inverter clipping, temperature and more.

• Speed + scale: go from request to results in weeks, not months and at a fraction of the cost.

Key features of Mass LTYA

Mass LTYA starts with 3E’s expert configuration of each site: system layout, technologies, electrical and mechanical parameters. From there: •	Input assumptions are auto-adjusted using 3E’s loss factor library •	TMY weather data is applied per site •	A dynamic simulation (comparable to PVsyst) is run using digital twins •	Quality control is integrated throughout to avoid data errors or manipulation The result? Reliable, bankable energy yield estimates you can trust, portfolio-wide.
Mass LTYA combines 3E’s expert site configuration with automated assumptions, weather data, digital twin simulations and built-in QA, delivering reliable, bankable yield estimates across your entire portfolio.

Proven accuracy, fast delivery & cost efficiency

We benchmarked Mass LTYA against detailed, traditional assessments across ~30projects. The results? An average deviation of less than 1.6%, with some as low as 0.1%. That’s well within investment-grade thresholds, and all delivered in a fraction of the time and cost!

High accuracy, full portfolio visibility, faster timelines and 10x cost efficiency: Mass LTYA redefines what’s possible in PV forecasting.

Where Mass LTYA delivers the most value

• Financing large portfolios: provide banks and investors with standardised, high-confidence P90 reports, at scale.

• M&A due diligence: quickly evaluate acquisition targets, even across fragmented asset sets.

• Asset management & reporting: update internal forecasts and investor dashboards with accurate portfolio-wide AEP figures.

Case study: €49M in financing secured with Mass LTYA

Read more about how 3E’s mass LTYA approach helped GreenYellow secure €49 million in financing for their GROW portfolio comprising over 2,318 rooftop PV self-consumption plants.

What’s included in our Mass LTYA

Every Mass LTYA engagement includes:

• P50/P90 energy yield estimates per site

• Detailed loss diagrams per asset

• Executive summaries + portfolio roll-ups

• Optional integration into the SynaptiQ platform for monitoring and performance tracking

Take control of PV forecasting at scale

Mass LTYA gives you back control at scale

Whether you're seeking financing, managing performance, or evaluating acquisitions, Mass LTYA delivers the speed, consistency and accuracy you need — portfolio-wide.

Say goodbye to spreadsheets, sampling and site-by-site bottlenecks. Say hello to scalable solar intelligence.

Ready to assess your portfolio at scale?

Reach out to us through this contact form.

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