Unnecessary loss of yield
The outcome of Autarco’s study shows that, even when using high quality products, in many cases this loss of efficiency can be prevented with good maintenance, supporting software and accurate use of (historical) weather data. After all, based on this, we are able to issue our high insured kWh guarantee.
What sets Autarco apart
During the design phase of a solar power system, Autarco makes a ‘Digital Twin’, or a digital copy, of the physical system design. Before we issue a kWh guarantee, every new system is verified against this Digital Twin. For example, we check the installation plan and the complete installation of the inverter and solar panels. This ensures that the system is installed safely and according to the correct specifications.
Even after installation and issuance of the kWh guarantee, Autarco continues to monitor each system. If a solar power system performs less than 95% of what it should deliver according to the ‘Digital Twin’, we will contact the installer so that he can check the installation again and solve any problems. Autarco only provides this aftercare for solar power systems with a kWh guarantee.
The Netherlands has had a higher irradiance in recent years compared to the historical average. Therefore, it is more likely that underperformance of a solar power system will remain undiscovered. The system can achieve the expected yield stated in the quotation, but if it was an extremely sunny year, the system could still underperform by up to 15%.
At Autarco, we allow for some natural variation in modeling and data accuracy, and define any system that performs less than 95% of its weather-adjusted forecast as under-performing.
Autarco bases its conclusion on data from 2679 solar power systems, of which 1638 have a kWh guarantee and 1041 do not. The systems without a kWh guarantee have not received a professional check after installation. These systems also lack corrected performance monitoring based on current weather data. The investigated solar power systems consist of Tier-1 quality solar panels and inverters.
These systems are using identical hardware with a common set of installers. The only material difference is whether the system has received the special care and attention that Autarco gives to systems with a performance guarantee.
Our findings are also supported by an expanded 2020 Energy Validation Study completed by DNV GL, a leading energy consultant and engineering firm, that demonstrate that the median performance of commercial projects below 50kW is only 94.6%.