As solar energy continues to grow as a sustainable power source, the tools used for designing solar projects play a critical role in optimizing both the efficiency and accuracy of these systems. Two of the most widely used software tools in the commercial solar industry are HelioScope and PVsyst. Each offers unique capabilities, but understanding their differences and how to align their outputs is essential for solar professionals seeking to maximize project outcomes.
This was the topic of our recent webinar — watch it here after reading through the blog below to get even more details.
HelioScope vs. PVsyst: key differences and functionalities
PVsyst is the gold standard for detailed and highly accurate simulations. It requires more detailed input, making it complex and time-consuming. However, the depth of its analysis provides a high confidence level in the simulation outcomes, which is crucial for the final stages of project design and securing financing.
HelioScope is an innovative tool for modeling the performance of PV systems, even under non-ideal solar conditions. It aligns closely with PVsyst results, showing a less than 1% difference when assumptions are aligned between the two tools. HelioScope effectively also combines multiple shading effects, such as row-to-row and nearby object shading, to achieve consistent outcomes, and accurately reflects the expected shade response improvements and the minor insertion loss from optimizers.
HelioScope is renowned for its user-friendly interface and rapid output capabilities. With HelioScope, solar professionals — even those without deep engineering expertise — can quickly generate accurate, efficient commercial solar project designs, saving time and money.
Key features and comparison
Near-shade profile
- PVsyst includes support for estimating near-shading impact but requires experience to choose the appropriate desensitizing factor for accurate modeling. This factor is crucial for simulating the performance of crystalline silicon modules.
- HelioScope generates a shading profile, creating geolocated bitmap images that show shading throughout the year. This detailed visual representation aids in estimating shading accurately.
Transposition model (Perez or Hay)
- PVsyst uses the Perez model for accurate diffuse irradiance data and the Hay model for robust performance when diffuse data is approximate.
- HelioScope similarly allows users to choose between the Perez and Hay models, ensuring flexibility in how irradiance data is transposed to the plane-of-array (POA).
Mismatch estimation
- HelioScope models the effect of irradiance and temperature variability within the array, considering cloud cover and module orientation variations. It uses IV curve mismatch to accurately simulate these variations.
- PVsyst applies adjustments to irradiance and power conversion stages but does not model from the module level up for intermediate PVsyst designs. It accounts for common module-level effects through these adjustments.
Diode modeling
- PVsyst models individual bypass diodes within a module, providing detailed insights into module performance under various shading conditions.
- HelioScope represents module performance with a single-diode IV curve driven by effective irradiance, simplifying the modeling process while maintaining accuracy.
Aligning outputs for accuracy and efficiency
Aligning the outputs of HelioScope and PVsyst ensures that projects initially designed with HelioScope can meet the rigorous standards required during the final analysis with PVsyst. Key to this alignment are:
Consistent project inputs: This ensures both tools use identical project details such as location, orientation, and mechanical configurations.
Weather data and environmental factors: It’s crucial to choose the same weather dataset and adjust for environmental losses, such as soiling. HelioScope users can adjust soiling losses to account for local conditions like snow in northern regions.
Equipment specifications: Matching the specifications and settings of PV modules and inverters across both platforms ensures consistency in performance estimates.
Practical implementation in HelioScope
In a recent webinar, we discussed how to ensure that HelioScope’s outputs closely align with PVsyst’s. This includes adjusting settings for array configurations, inverter specifications, and even the specific environmental conditions reflected in the weather data used. For instance, ensuring that the ground coverage ratio and the tracking strategies in HelioScope match those in PVsyst can significantly affect the accuracy of the output data.
To align HelioScope with PVsyst, users can create a condition set within their profile, which is particularly useful for standardizing assumptions across different projects and regions. The process involves several steps:
Creating project location & details:
- Navigate to the library section in HelioScope, click on “profiles,” and select “new profile.”
- For example, you can create a profile for a specific region, such as the northeast.
Setting soiling losses:
- Enter soiling losses by month. This parameter can also be adjusted to reflect light-induced degradation (LID) or bifacial module efficiency gains. For instance, add 1.5% for LID across all months or subtract 3% for bifacial gains.
Adjusting cell temperature:
- Switch to the diffusion model, equivalent to what’s used in PVsyst, to ensure consistency in temperature-related performance impacts.
Managing mismatch and AC losses:
- Set the mismatch percentage based on historical data and scientific studies to model real-world output variances.
- Enter any AC losses, including transformer and wiring losses, to ensure all potential losses are accounted for.
Selecting the transposition model:
- Choose the Perez or Hay model, depending on the standard used in PVsyst.
Configuring Tracking and Backtracking:
- Adjust the tracking settings to match those used in PVsyst and enable backtracking if applicable.
By following these steps, solar professionals can build standardized profiles in HelioScope that align closely with PVsyst’s assumptions and settings, ensuring consistent and accurate output predictions.
HelioScope’s accurate system designs produce reliable production numbers you can stand behind. With features like module-level array modeling, real-time cloud computing, and integration with user-friendly mapping and structural design tools, HelioScope stands out as a significant technical advancement in PV system performance modeling.
For solar professionals, understanding how to utilize and align HelioScope with PVsyst can be crucial for streamlining the design process without compromising on the accuracy needed for project approval and financing. By effectively using both tools, designers can optimize their workflows, improve project turnaround times, and ensure high accuracy in solar production estimates, making the most of both rapid design capabilities and detailed analytical precision.
Now that we understand the basics, our next post looks at some HelioScope and PVsyst frequently asked questions we’ve been hearing in the field. Stay tuned!
