Ratios

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

Ratio

Units

How calculated

Notes

Design performance ratio (photovoltaic projects)  

%

Rated output capacity in MWAC ÷ Solar array capacity in MWP

Actual performance ratio varies with temperature & other factors

Annual energy yield  

hours

Design output in MWh ÷

Rated output capacity in MWAC

Assuming standard irradiance levels

Equivalent households  

homes/MWAC

Annual energy yield ÷ average house electricity consumption

Varies with energy intensity of local households

Emissions saving  

tCO2/

MWAC

Annual energy yield ÷ average carbon intensity of electricity

Varies depending on regional fuel mix for electricity generation

Equivalent cars  

cars/ MWAC

Emissions saving ÷ average annual emissions per vehicle

Varies with regional fuel economy of vehicle fleet

Land area  

Ha/

MWP

Solar array (fenced) area ÷

Solar array capacity in MWP

Varies with latitude and type of mounting structure / tracking

Capital cost  

$m/

MWAC

Capital cost of project ÷

Rated output capacity in MWAC

Based on build or resale cost - not always comparable

Financial gearing  

%

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

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  below), or the 'Supra' version of a Project Report (ratios shown or § below).