Project statistics

There is a host of statistics we love to talk about on our projects. This page explains some of the key terms we use when talking about our projects and sustainable energy.

Key stats

Certain key statistics are common across most of our sites, with some slight variation between different technologies like wind or hydro.

Site capacity

The maximum output of electricity which could be generated by the project at any moment in time with the right conditions.  It is usually stated in megawatts (MW) except solar projects which are usually stated in megawatt peak (MWp).

Annual forecast output

Like any generating station (fossil fuelled, nuclear or renewable), we will not be generating at the site's maximum capacity all year round.  The annual forecast output describes how much electricity we expect to generate and export in a "normal" calendar year.

With a variable resource such as wind or rainfall the actual output may be higher than this in some years and lower in others.  Our pre-construction studies model what an average year should generate based on historical data recorded at site, wider meteorological information and certain informed technical assumptions.  The relationship between the actual output and the theoretical maximum output is known as the "capacity factor".

The forecast output is presented in gigawatt hours (GWh) where 1GWh = 1,000 MWh (megawatt hours) or 1,000,000 kWh (kilowatt hours).  i.e. 1GWh is equivalent to a million electrical units recorded on an electricity meter like we have in our homes.

UK homes equivalent

To help understand the scale of these commercial projects we also show how many UK homes this annual forecast production could supply for the whole year.  The conversion is calculated using the latest figures published by the Department for Business, Energy and Industrial Strategy, currently 3,781kWh per UK home per annum.

Maximum tip height (wind farms only)

All of our wind farms comply with specific planning permissions which, importantly, take into account the visual impact of a single turbine and the cumulative impact of multiple turbines in one geographical area.  This is usually set according to the maximum tip height which is the highest point above ground level which any part of the wind turbine blade will reach during a full rotation.

In most cases a greater tip height will allow for longer blades and benefit from higher wind speeds further above the ground, so a more efficient and cost effective conversion of wind into electricity.

Operational since

The date on which the project first became operational and started exporting renewable electricity.

Live stats

For some of our project sites we are also able to show "live" data - how windy it is on site and how much we are producing from that site right now.  The stats are updated every 10 minutes or so with the time of the last update shown in a date and time stamp next to them.

The variety of ways we connect to our turbines and the format of the data we access means it is not possible to show live stats for every project.

Wind speed

Wind speed is measured in metres per second (m/s) from anemometers at the top of the turbine tower.  Wind turbines usually reach their optimum generating capacity in winds of around 10 to 15 m/s (roughly 22 to 33 miles per hour).


Production is a snapshot of how much electricity is being generated at this given point in time.  It is displayed in the standard kilowatt (kW) units.

So far today / this month / this year

Our live statistics show a cumulative total of how many units of electricity (in kilowatt hours) have been generated from the site today, since the start of the current month and since the start of the calendar year.  The kilowatt hours (kWh) are the same units as measured by a domestic electricity meter.

To put this in context we then convert these kilowatt hours into homes equivalent - i.e. how many UK homes this amount of electricity could power for an entire year.  The conversion is calculated using the latest figures published by the Department for Business, Energy and Industrial Strategy, currently 3,781kWh per UK home per annum.