Methodology and data sources
GreenPie is a screening tool built on modelled, historical data. This page describes what the calculations actually use and where their limits are.
Check your locationData sources
Wind and solar resource data come from the Open-Meteo archive. Long-term wind uses the ERA5 climate reanalysis (Copernicus/ECMWF); solar uses modelled radiation. Terrain elevation is an approximate grid-cell value.
Wind methodology
Wind is analysed at a 10 m reference height from hourly ERA5 data. GreenPie reports average, median, percentiles, the seasonal profile and year-to-year variation over 2, 5 or 10 years. Hub-height estimates use a simple power-law shear, not a micrositing model.
Solar and PV methodology
Solar uses global, direct, diffuse and tilted irradiation. PV output is estimated from a reference system (5 kWp, south, 30°) with a generic performance factor of 0.80 — an aggregate allowance, not a component-by-component loss model.
Turbine power curves and AEP
Turbine energy combines a documented power curve with hourly wind transformed to hub height, plus a dry-air density adjustment. Annual energy is the mean of eligible complete calendar years.
Seasonality, complementarity and consumption
Seasonal profiles are observed monthly statistics. Complementarity measures whether wind strengthens when solar is seasonally weak. Household consumption is compared monthly with the modelled resource.
Limitations and beta status
ERA5 describes a grid cell (about 0.25°), not the exact property. Results are modelled, not measured, and are not an engineering certification, a site survey, investment advice or a guaranteed production forecast. GreenPie is in free public beta.