Data analysis
The Wiki-Solar Database holds many different parameters
Ratios and derived parameters - how they are calculated
The data we hold on each project enables us to calculate a number of key parameters related to the design and intended performance of utility-scale solar power plants. These are based on the published data for the project (often at the time of design or installation) so actual operational ratios may differ.
These ratios are available to Wiki-Solar customers, when they buy a Market Overview (ratios show Ო below), or the 'Supra' version of a Project Report (ratios shown Ო or § below).
Ratio | Units | How calculated | Notes |
Design performance ratio (photovoltaic projects) Ო | % | Rated output capacity in MWAC ÷ Solar array capacity in MWP | Actual performance ratio varies with temperature & other factors |
Annual energy yield Ო | hours | Design output in MWh ÷ Rated output capacity in MWAC | Assuming standard irradiance levels |
Equivalent households Ო | homes/MWAC | Annual energy yield ÷ average house electricity consumption | Varies with energy intensity of local households |
Emissions saving Ო | tCO2/ MWAC | Annual energy yield ÷ average carbon intensity of electricity | Varies depending on regional fuel mix for electricity generation |
Equivalent cars Ო | cars/ MWAC | Emissions saving ÷ average annual emissions per vehicle | Varies with regional fuel economy of vehicle fleet |
Land area Ო | Ha/ MWP | Solar array (fenced) area ÷ Solar array capacity in MWP | Varies with latitude and type of mounting structure / tracking |
Capital cost Ო | $m/ MWAC | Capital cost of project ÷ Rated output capacity in MWAC | Based on build or resale cost - not always comparable |
Financial gearing Ო | % | Non-equity finance ÷ Capital cost of project | Proportion of the cost not met by the owner's equity |
Construction period § | Days | Coming online date (CoD) - Construction start (groundbreak) | |
Lifetime § | Years | Decommissioning date - Coming online date (CoD) | Decommissioning dates may sometimes be extended |
Average solar module capacity § | MWP | Total rated solar array capacity ÷ number of solar modules | |
Average inverter capacity § | kVA | Rated system output capacity ÷ Number of inverters | |
Average storage period § | Hours | Rated battery capacity MWh ÷ Battery power rating MW | Time a fully charged battery can deliver power at rated output |
Storage ratio § | Hours | Rated battery capacity MWh ÷ Solar array capacity MWP | The period the solar array would need to fully charge the battery |
Tariff / power purchase price § | $/MWh | Price or tariff obtained / MWh exported | May alternatively be quoted in ¢/kWh (10¢/kWh = $100/MWh) |
Annual system income § | $m/ year | Export tariff/price (above) x Rated system output MWh/year | |
Simple payback § | Years | Annual income (above) ÷ Capital cost of plant | Does not take account of operating or finance costs |
Average project size § | MW | Total project capacity ÷ Number of projects | Typically calculated on a regional basis |
Worldwide average ratios
The following table shows indicative worldwide averages as of mid 2020.
We also calculate these ratios on a regional basis for continents, countries and provinces, and derive year-by-year values.
Ratio | Average | Notes |
Performance ratio | 80.1% | 84% in Europe (cooler); 77% N. & C. America |
Energy yield | 2,045 hrs | 1,525 in Europe; 2,535 in South America |
Equivalent households | 914 homes | ~800 in N America; ~2,100 in Africa |
Emissions saving | 685 tonnes | 550 in North America; 800 in Asia |
Equivalent cars | ~200 cars | Data mostly from North America |
Land area | 2.1 Ha | Median is lower. Reducing with time |
Capital cost | $4.2m/MW | Decreasing: ~$11m in 2011; ~$3m in 2018 |
Gearing | 60-70% | Variable, and data relatively sparse |
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