Parhelion
The digital twin of your plant
A physics-based model that knows what the plant should be producing. In blind tests it found 91% of faults and identified the correct string for 98.6% of its findings.
Solar asset management from A to Z
We watch the output and handle faults, claims and repairs. For you.
What we do
Monitoring
We know what the plant should be producing
We compare actual output with the digital twin. You see the loss in kWh and in euros before it reaches the invoice.
Diagnostics
We find where and why the plant loses output
Parhelion shows the affected string and estimates both the likely cause and how the loss will develop over 30 to 180 days.
Claims and warranties
We help you claim on the warranty in time
Measured data and technical documentation serve as evidence in dealings with the manufacturer, the installer and the insurer.
Service
We order the repair and verify the result
We coordinate the service companies and, after each job, measure that the output has really come back. You just approve.
Independent data from more than 125 GW of plants
Underperformance is the rule, not the exception
Plants routinely produce less than they could. Losses from faults are rising fast, and routine inspections miss some defects altogether.
-
5%
of output lost by a typical plant compared with the model. For 750 kWp at €0.17/kWh, that is roughly €6,600 a year.
NREL PV Fleet 2024 · 1,128 systems, 8.5 GW
-
+115%
rise in losses from equipment faults between 2021 and 2025, from 2.36% to 5.08% of output.
Raptor Maps, Global Solar Report 2026
-
79%
of high-risk connector faults have no thermal signature, so a thermal camera won't pick them up.
kWh Analytics, Solar Risk Assessment 2026
Plants that are watched lose less
Plants inspected once a year lose around 7% of their output. With five inspections a year, it is roughly 3%.
Raptor Maps, Global Solar Report 2026. This is a correlation, not a proven cause.
Read the study
The Sunalytiq platform
Meet Parhelion
A parhelion is a rare phenomenon in which a faithful image of the sun appears beside it. That is exactly what we do with your plant.
Parhelion is the digital twin of your plant. Using the documentation and actual weather, it calculates what the plant should be producing and compares every string with its neighbours and with the model. Every difference is turned into a location, a loss in euros and a likely cause.
1,558modules
693 kWpinstalled capacity
15skylights and obstacles
Sample visualisation: a real warehouse and its model. Move the divider or rotate the model.
- Data
What the plant already collects
String-level power data from the inverters and public satellite weather data. Nothing is installed and no rooftop sensor is needed.
- Model
A physics-based twin
It takes the tilt, orientation and size from the documentation, or works them out directly from the production record. Then it calculates, hour by hour, what the plant should produce.
- Comparison
Every string under watch
Every hour, each string is checked against its neighbours and against the twin. The gap becomes kilowatt-hours and money.
- Results
Finding, forecast, outlook
Which string, since when, how many kWh and the likely cause. A neural network adds tomorrow's output forecast and how the loss will grow over the next 30 to 180 days.
- 91%
- of faults found in blind tests
- 98.6%
- of findings point to the correct string
- 4.8%
- false alarms, compared with 100% for the conventional method
- 2×
- more accurate next-day output forecast than an estimate based on the day before
Verified in blind tests on 1,500 pre-registered simulated plants under real measured skies; the forecast was also tested on a real plant. Validation results
What you get
Fewer losses, lower operating costs and decisions that are calculated before you pay for them.
- 7 days
- median time from the onset of a sudden fault to its detection
- 96 of 96
- sudden losses of 2% or more detected
- 0
- false findings over 69 days of operation
- 11%
- error in the next-day output forecast, against 24% for an estimate based on the day before
Results from the first real plant: 10 kW, two strings, 400 faults injected into the actual production record. We are now verifying real faults in the pilot programme.
Output and stability
Fewer losses, more output
We find faults, soiling and shading before they add up to lost years.
The problem caught early
A slow decline that triggers no alarm shows up as a deviation from the model.
Fault outlook
We estimate how a detected loss will develop over 30, 90 and 180 days if nothing is done about it.
An operating limit is not a fault
We recognise an export limit, zero-export operation or an overheated inverter and don't raise needless alerts.
Losses that clear on their own
We distinguish snow, soiling that washes off or a brief outage from a fault that persists.
Post-event check
After a hailstorm or a gale, we compare output with the twin and show what has changed.
Costs and service
Lower operating costs
You pay for service when it is genuinely needed, not by the calendar.
Fewer pointless site visits
The technician knows in advance where to go and what to bring. The repair is faster.
Predictive maintenance
Cleaning, inspections and replacements are planned from data, not blindly.
Less risk of expensive repairs
We fix a small defect before it turns into an expensive repair.
Validation after repair
After every job, we measure that output has really come back.
Coordination handled for you
We handle service, claims and insurance cases. You just approve.
Decisions and investment
Automatic loss calculations
Finding problems, calculating losses and proposing fixes all run without any work on your part.
Payback known in advance
The software calculates the cost of the repair and its payback before you order anything.
Losses with a trend, not a snapshot
The model calculates how the loss will grow over the next 30 to 180 days.
Output forecast
You know what the plant will produce tomorrow, hour by hour, with an uncertainty band.
Scenario modelling
Add modules, a battery or a fault in the virtual environment and see the impact straight away.
Protecting the investment
A better return on the plant and technical documentation for the bank, the insurer and the manufacturer.
You know what to fix, what it costs and when it pays for itself.
For every finding, the software calculates the loss, the cost of the fix and the payback. The decision then takes a single click.
- Losses with a trend
- Not today's figure multiplied by years. The model calculates how the fault will spread.
- Ranked by money
- What pays back fastest comes first.
- Paperwork handled
- We prepare the costings and the technical reports.
Array C is producing 6% less
High priorityMost likely module soiling
Loss if nothing is done12,690 €growing 8% a year
- Cleaning cost
- €560
- Payback
- 8 months
Order cleaningDetails
Parhelion
Every module.
Every module.
Exactly where it belongs.
A sample model of a logistics warehouse: 1,558 modules, each one in its place.
- 1,558modules in the model
- 24 houtput forecast with an uncertainty band
- 30–180 daysoutlook for how a detected fault develops
portal.sunalytiq.com
ParhelionPlantsFindingsServiceReportsPortfolio · 4 plants
Prague South Logistics ParkHall D2 · 693 kWp
DayWeekMonth
Output today2,184 kWh
Per the model2,312 kWh
Loss today−€24
Array C · −9%
6:0010:0014:0018:00
Finding #219 · High priority
Array C is producing 9% less
Requires a thermal drone inspection
- Loss
- €2,590/year
- Inspection
- €516
- Payback
- < 3 months
Not just software. We handle all of it for you.
The portal shows where your plants are losing output and what it is costing the business. Our team then sees the repair, the claim and the insurance case through to the end. One partner, one point of responsibility.
- The software findsThe cause, the location and the cost of the repair.
- You approveIn one click, with the price known in advance.
- We arrange itThe service work and proof that output is back.
No new hardware · Your data stays yours · Outputs for audits, banks and insurers
From detecting the fault to a verified repair
What is typically available today for 30–500 kWp plants without a service contract, and what we take on.
StepCommon practiceSunalytiq
Record of actual outputFree, basicYes
Model of expected outputUsually notYes
Loss in kWh and in moneyNoYes
Likely causeNoYes
Repairs ranked by paybackNoYes
Thermal and drone inspectionRarelyThrough partners
Ordering and managing the repairNoYes
Pursuing warranty claimsNoYes
Proof that the repair workedNoYes
Source: Solar PV Underperformance 2026, sections 17 and 20.
The measurement that returned 4,500 modules
In its third year of operation, a 30 MWp plant discovered that 15% of its modules were degrading at 2.5% a year, while the warranty allowed no more than 0.7%. The claim covered 4,500 modules and the manufacturer replaced them. The lost output was worth roughly €200,000.
Without measured data, nobody would have noticed. That is why we collect evidence continuously, handle claims with manufacturers and installers, and keep track of the deadlines.
Book a consultationA documented industry case: PV-Maps, January 2026. Manufacturers also reject claims if you cannot provide evidence of maintenance and measurements.
How much your plant is losing
A quick estimate based on the model from the Solar PV Underperformance 2026 study. Enter your own figures.
This year you are likely losing
lei
- Energy lost this year
- Already lost since commissioning
- Loss over the rest of the 30-year lifetime
- With active management you save (conservatively)
Explore the live demo
Explore Parhelion
Fully integrated software
From connecting the data through diagnostics to the verified repair, everything runs in one system. Parhelion tracks every string against the digital twin, converts deviations into euros and prepares the service brief, the claim documentation and the report for the bank by itself. With every plant and every repair, it becomes more accurate.
Built for commercial and industrial plants
The digital twin can handle a plant of any size. But we start where losses hurt most and where nobody is dealing with them yet.
Nobody measures them in detail
Large solar farms have a control room, homes have the manufacturer's app. Commercial roofs fall in between.
Their numbers are growing fast
After the boom of recent years, thousands of plants sit on industrial and commercial buildings, and they are now ageing.
Nobody actively manages them
The company has no energy manager, and nobody keeps an eye on the plant until something obviously goes wrong.
The losses are worth fixing
From roughly 75–100 kWp, the recovered output reliably outweighs the cost of management.
Manufacturing and logistics
Overheated roofs, difficult access and no technician on site.
Commercial buildings
The plant is running, but nobody is accountable for its output.
Farms and agribusiness
Dust and pollen increase soiling. Service is often far away.
Plant portfolios
Several sites, one overview and one partner.
A smaller plant, a solar farm or an installer? Write to us and we will tell you what makes sense.
20.6%
of the energy over 30 years is lost by a plant that nobody watches
A fifth of all output over the lifetime, once the losses from every year are added together. With occasional checks it is 11.9%, with active management 4.7%.
- 8 → 31%
- the loss grows as the plant ages. In the first year, about 8% of annual output is missing against the investment model; by the thirtieth year, it is 30.8%.Study model, section 6
- €54k
- the difference between active and neglected management per 100 kWp over the lifetime, roughly €540 for every kWpStudy calculation, section 6.2
- 2.36 → 5.08%
- the output loss from equipment faults has more than doubled in five yearsRaptor Maps, Global Solar Report 2026
We will publish our own case study from the pilot programme as soon as the results are verified.
Solar PV Underperformance 2026
49 pages on how much solar loses, why, and what it costs. Based on data from NREL, IEA PVPS, Raptor Maps and kWh Analytics.
Pilot programme
Be among the first to sign up your plant
Parhelion will monitor your plant free of charge. You get the findings and the output forecast; we get real data and your feedback.
- €0for Parhelion and our work for the entire pilot
- 0 deviceson the roof. The data your inverter already collects is enough.
- Any timeyou can end the pilot. An email is all it takes.
Frequently asked questions
What the service includes, how we connect to your plants and what happens to your data.
What we do for you
What is a digital twin of a plant?
A physics-based model of your plant that uses the documentation and actual weather to calculate what the plant should be producing. If the documentation is missing, it works out the tilt, orientation and size directly from the production record. Every difference from reality is a lead to a problem: Parhelion shows the affected string, the loss in kWh and the likely cause.
What size of plant is the service for?
For commercial and industrial plants. According to our study, the service makes the most economic sense from roughly 75–100 kWp, because only then does the recovered output reliably outweigh the cost of management. For smaller systems, we will gladly tell you whether it pays off.
What exactly do you do for us?
We compare actual output with what the plant should have produced and look for the cause of the difference. When we find a fault, we describe it, propose a fix and arrange the repair with a service company. Afterwards, we check in the data that output has really come back.
In parallel, we track warranties and deadlines so that you can claim the defect with the manufacturer before the warranty runs out.
Will you replace our service technician?
No. You still need your service company. We provide what is usually missing between monitoring and service: data analysis, prioritisation, the work order and the check on the result. If you have your own service provider, we work with them.
Who handles the claim with the manufacturer?
We prepare the documentation: measured data, a description of the defect and proof that the plant was properly operated and maintained. Without it, manufacturers routinely reject claims. The claim is filed by the plant owner; we manage it and keep track of the deadlines.
What if the plant is already out of warranty?
It still makes sense. Most lost output comes not from defects covered by the warranty but from operational issues: soiled modules, unresolved inverter errors, switched-off strings and outages dealt with too late. We handle those regardless of the warranty.
Connection and go-live
Which inverters and monitoring systems can you connect to?
We start with the data your plant already collects: from the inverter manufacturer's portal, a datalogger or your existing monitoring. We confirm the specific brands and the connection method at the first consultation.
What if we already have monitoring?
That is an advantage, because it gives us something to start with. Monitoring shows what the plant produces. We add what it should have produced, why there is a gap and who should fix it. You keep your existing portal.
Do we have to install anything?
In most cases, no. We work with the data the plant already collects. If data is missing or too coarse, we will tell you upfront and suggest what to add, whether string-level measurement or a one-off thermographic inspection.
How long does go-live take?
It depends mainly on how quickly we get access to the data. Once access is granted, we build the expected-output model and a first loss overview, which we go through together.
Pilot programme and pricing
How does the pilot programme work?
We always begin with a pilot on your real plants, not on demo data. We connect to the production data, build the expected-output model, show you where and how much you are losing, and resolve the first losses together.
You pay nothing for the software or for our work during the pilot. In return, we ask for your feedback and real cases from operation, which guide how we develop the product.
How long does the pilot last?
It has no fixed duration or end date. It runs until you can see the result in the data, meaning the difference between what the plant produced before and after the fixes. For some faults that takes weeks; for seasonal issues, a whole season.
What do you need from us at the start?
Access to the production data, the basic technical details of the plant (capacity, module and inverter types, year of commissioning) and the contact details of the person who looks after the plant on your side. If you have inspection reports, design documentation or warranty certificates, they will help us with claims.
Who pays for repairs, parts and travel?
You pay for the service companies' work, spare parts and travel, because the work is done on your property. We always price it first, though, and place the order only after you approve the quote. If the defect is covered by a warranty, we try to pass the costs on to the manufacturer or the installer.
Can we end the collaboration at any time?
Yes. The pilot does not commit you to anything, and either side can end it at any time. We will propose the price of any further collaboration in advance, and you do not have to continue. The data about your plant remains yours, and we will hand it over to you.
Your data
Who has access to our data?
The data is visible only to authorised members of the Sunalytiq team and to the people you grant portal access to yourself. We do not sell the data or use it for any purpose other than analysing performance and handling service for your plants.
Do you share data with service companies?
Only to the extent the job requires, and only after your approval. The service company receives the fault description and its location, not access to your whole plant or its production history.
Where is the data stored and how is it protected?
The website and the client portal run on servers in the European Union and communicate over encrypted HTTPS. Only signed-in users can access the portal, and accounts can be protected with two-factor authentication.
What happens to the data when the collaboration ends?
We hand the data over to you and delete it on request, unless we are required by law to keep it. You will find the details in our privacy policy.
Book a consultation
Tell us a little about your plant. We will show you where it is losing output and what we will do about it.