How Onyx Renewables halved design-to-PVsyst time by building the model once

Onyx Renewables designs in Solesca and exports the shade scene natively to PVsyst, which removed the manual rebuild that used to sit between the two tools. A full production estimate now takes one to two hours instead of two to four. PVsyst calculates electrical losses against the real module layout rather than an approximation of it, so early-stage energy estimates moved from indicative to definitive.

50%

Less design-to-PVsyst time

1–2 hours

Per production estimate, down from 2–⁠4

Zero

External layout requests outsourced during RFPs

A rooftop array designed in Solesca, laid out around HVAC units and skylights

About Onyx Renewables

Onyx Renewables develops, finances, builds, owns and operates onsite clean energy for commercial and industrial businesses. The single-owner model eliminates handoffs, accelerates builds and keeps quality consistent from concept through long-term operations, which means the engineering team lives with every design decision it makes through the operating life of the asset.

Four engineers carry that entire load, owning the full project lifecycle: preliminary design, initial diligence, construction and final completion. There is no separate modeling group. Whatever the design workflow costs in hours, it costs the same four people. That is why design accuracy at the front of a project matters more here than at a developer who sells the asset on.

Onyx Renewables at a glance
Detail	Onyx Renewables
Industry	Onsite clean energy for commercial and industrial businesses
Portfolio	400+ projects in operation; 11+ GW of development experience
Project types	Carport, roof-mount, ground-mount and tracker systems, plus solar and storage
Engineering team	Four engineers, led by the VP of Engineering
Solesca use	Preliminary layouts through construction-stage design, with PVC export to PVsyst

The workflow, before and after

One step changed, and that step was the expensive one. Onyx engineers were building every shade scene twice: once to design the system, once more inside PVsyst to model it. Removing the rebuild did two things at once. It halved the clock, and because the shade scene now transfers natively, PVsyst runs its detailed electrical loss calculations against the actual module layout instead of an approximation of it.

The Onyx workflow before and after Solesca, per project
Step	Before Solesca	With Solesca
Design the system	In a preliminary design tool	In Solesca, about 30 minutes
Confirm diligence	Public software and databases: hosting capacity, wetlands, aerial imagery	Wetland layers generated in place of manual USFWS screenshots
Rebuild the shade scene	Recreate the design inside PVsyst by hand	Removed. The native PVC export carries the design across
Model production	In PVsyst, on approximated geometry	In PVsyst, on the real module layout, about 30 minutes
Total	2–4 hours per project	1–2 hours per project

The challenge

1. Building the same shade scene twice

Before Solesca, an Onyx project moved through a chain of tools that never quite connected. The team designed the system in a preliminary design tool, confirmed site conditions against publicly available software and databases, then modeled production estimates in PVsyst. If a shade scene was required, the engineer manually recreated the design inside PVsyst. Start to finish, that ran two to four hours per project depending on size and complexity. The design already existed. It just could not travel between the two tools.

“Redoing the shade scene and layout of the array, especially for rooftop systems, was a clear pain point for the team and a source of redundancy.”
– Onyx Renewables engineering team

2. Estimates that stayed indicative

The accuracy cost was the part that mattered more. Without a PVC export out of their preliminary design tool, Onyx could not model stringing losses accurately, which left early-stage energy estimates indicative rather than definitive.

Rebuilding the geometry inside PVsyst introduced its own ceiling. PVsyst provides robust shading analysis, but Onyx found that generating detailed rooftop shade scenes, particularly for complex subarray configurations and bifacial modeling, proved challenging. Rooftop systems were the hardest hit, and rooftop is where much of the C&I portfolio lives.

Why Onyx chose Solesca

Onyx evaluated design software on three criteria, and wanted something with features similar to the preliminary design tool the team already knew:

Price
Efficiency of design
Ease of use: flexibility in design and a seamless user experience

What Onyx ultimately appreciated was Solesca’s flexible, web-based approach to solar system design. The native PVC export into PVsyst was the key standout feature, removing the manual rebuild from the workflow and improving modeling accuracy at the same time. The wetland generation tool carries much of the remaining day-to-day weight, replacing a step where the team manually imported and scaled screenshots from the USFWS National Wetlands Inventory for every site.

A fixed-tilt ground-mount layout following the terrain, designed in Solesca

“The integrations with PVsyst and PVC exports have been a game-changer for our team’s workflow, and it seems like new helpful features are released very frequently.”
– Onyx Renewables engineering team

The results

1. Half the time to a PVsyst-ready model

Design and modeling time still depends on project complexity. But a typical Solesca design takes the Onyx team about 30 minutes, with another 30 minutes in PVsyst, putting a full production estimate at one to two hours against the two to four the old workflow required. Both figures cover design plus production modeling for one project.

2. One model, accurate at the module level

Because the shade scene transfers natively, PVsyst’s detailed electrical loss calculations run against the actual module layout. With more accurate shade scene capabilities, Onyx is more confident in both its early-stage and its operational production estimates. For a company that owns and operates what it builds, that confidence compounds across the life of the asset.

“Using Solesca has greatly reduced the redundancies in our engineering design workflows and has improved our confidence in our production estimates throughout the project lifecycle.”
– Onyx Renewables engineering team

3. Capacity without adding headcount

When large RFPs open, design requests arrive in bursts. Under the old workflow, the engineering team had considered supplementing capacity to accommodate that workload. Instead, the faster workflow let Onyx avoid the costs it would otherwise have incurred from outsourcing external layout requests, and freed the team to spend more of its time on higher-value work.

“Without Solesca in our workflow, we would spend less time completing higher-value tasks for our organization. Previously, the Engineering team had considered supplementing capacity to accommodate our workload, especially when design requests for large RFPs were opened.”
– Onyx Renewables engineering team

4. A faster handoff to Originations

The internal effect is clearest downstream. Faster design-request timelines mean early-stage results reach the Originations and Pre-Construction teams at a much higher throughput, which lets Onyx complete RFPs with greater efficiency and accuracy, reducing bottlenecks between departments. Asked to pick the one metric that captures Solesca’s impact, the Onyx engineering team chose a single word: efficiency.

5. A design that stays in the project

The change with the longest tail is quieter. Onyx had used its previous tool primarily for preliminary design, useful at the front of a project, then set aside. Solesca stays in the workflow. The team now updates designs throughout the project lifecycle to ensure it has accurate, detailed shade scenes through project completion.

Final thoughts

Solesca did not replace PVsyst at Onyx and was never meant to. The production model still runs in PVsyst. What changed is that the geometry it runs against is the design Onyx already built. Any team evaluating this should read the result as removing a handoff, not removing a tool. The timings on this page are Onyx’s own measurements of their own projects rather than a Solesca benchmark, and design time depends on the size and complexity of the system in front of you.

Moving tools also came with friction. Onyx reports struggles around differences in the interface and design features during onboarding. What made the move work was the response on the other side. Solesca stayed responsive to questions and to feature requests throughout onboarding, and Onyx credits the openness of the working relationship: collaborating with the team, sharing future plans, and being transparent about decision-making on feature implementation.

“Working with the Solesca team has been great. They are a smart team that has brought some much-needed high-quality competition to the solar design software space. I really appreciate their responsiveness, not just for quick issues but for questions on their methodology. The software is very easy to pick up, and I appreciate the constant updates the team is working on behind the scenes!”
– Onyx Renewables engineering team

Improve accuracy, reduce rework, and streamline project evaluation with Solesca.

Book a 30-minute demo with our U.S.-based engineering team. No CAD setup required.

Book a demo