Solar & Battery Performance Modelling

Reliable, powerful performance engine

SolarPlus has been the industry-standard, best-practice design solution to meet solar requirements since introduction in 2012 by Solaris Pty Ltd in partnership with the Smart Energy Council.

In 2017, SolarPlus introduced an advanced performance algorithm which provides best-in-class modelling across a broad range of design configuration options including grid-connect, hybrid/backup battery storage, off-grid, system upgrades and supporting a wide range of load profile and tariff analysis options.

 

Weather and Irradiance Data

SolarPlus utilises the world recognised leader in irradiance data, Meteonorm, for reliable weather data including radiation data at an 8km resolution and generated using 20 years of recorded data.

Meteonorm was initiated by the Swiss Federal Office of Energy in 1985 and has developed to provide a global climate database based on ground measurement and satellite weather data and using state-of-the-art interpolation models to produce the Typical Meteorological Year data analysed by SolarPlus.

Download PDF for more information about Meteonorm.

Meteonorm Current Version 9 (as of 07/08/2026)

These are the main changes from Meteonorm 8 to Meteonorm 9:

• Complete overhaul of the algorithmic core and the API (previously called "web service"), including many bug fixes and improvements. Forecast and observation APIs are now integrated into the Meteonorm API. 
• 2001–2020 is now the default climate period for radiation, temperature, and other meteorological parameters.
• New station data from newly accessible open data sources (primarily from national meteorological services adopting open data policies).
• Enhanced quality and quality control mechanisms for surface observations.
• New satellite data: MSG 2008–2023, IODC, Himawari and GOES-E: 2018–2023.
• Improved algorithms for blending surface observations with satellite data.
• Introduction of new IPCC AR6 scenarios SSP1-2.6, SSP2-4.5, and SSP3-7.0. Our future TMY are based on the averages of 15 global climate models from the CMIP6.
• Topographical data is now based on the Copernicus GLO-30 digital elevation model, which is globally available and has a higher spatial resolution (30m) than the previously used SRTM dataset (90m resolution).
• Aerosol and Linke turbidity information has been updated. New climatologies based on Merra2¹ and the reference period of 2001–2020 are used instead of the blended dataset (Aeronet ground data, Merra2 and MODIS) in Meteonorm 8.

Solar Performance Simulation

SolarPlus performs an analysis of solar power generation using a module-level simulation that generates the expected module output for any orientation at each hour of the year (8760 hours). The components of direct, diffuse and ground-reflected radiation data from the sun are derated using the Perez model, and factoring shading, glass reflectance, and soiling to arrive at the irradiance impinging on the panel front, and if a bifacial module, adjusted for on the rear surface. Adjustments for temperature and wind for each hour, and accounting for proximity to the mounting surface, provide the derating of the cell according to its manufacturers specifications.

According to the system electrical configuration, module and string voltages and current are modelled with allowance for the variability due to module mismatch, manufacturing tolerances, and cabling losses at each stage of the power transmission. Inverter losses due to tracker and output stage current and power limiting are calculated and inverter efficiency and AC derating factored into the usable energy potential to the site switchboard.

Energy and Savings Simulation

SolarPlus supports energy simulation down to 10 minute resolution in order to simulate performance of battery storage systems, consumption power flows, grid interaction and, for off-grid systems, generator runtime.

Battery system performance is modelled according to the specifications of the manufacturing and factoring roundtrip efficiency, configuration set-point limits, depth of discharge limits, and accounting for battery chemistry characteristics.

Grid interactivity levels are controlled with export limits, set-points for any battery grid charge or battery export and all energy flows accounted according to the electricity tariff structure set for the site including time-of-use, tiered tariffs and demand charge rate.

Lifetime Return on Investment​

SolarPlus conducts an assessment of potential payback on investment factoring solar panel degradation, tariff escalation rates, reinvestment amounts in future years, maintenance costs.

More detailed return on investment analysis of lifetime savings can be generated including depreciation, costs of finance, subsidies. Discount rates are applied to estimate an Internal Rate of Return and Net Present Values of the system over the lifetime period.

Carbon emissions reduction is calculated based on grid energy reductions using the state emissions reduction coefficient published by the local governments.