In order to calculate the potential power output, return on investment, and payback period of a wind generator for your home, you will need to know the average wind speed in your area.
You can of course measure this yourself, however, a quicker and easier way is to access a wind speed database.
In this guide, we present several options of freely available online wind speed databases which cover the US, UK, and the rest of the world.
By understanding these tools, their features, and their limitations, you can find the best wind speed database for your location and individual requirements.
In the US, an interactive wind speed map is available from NOAA Climate.gov which offers data about average monthly speed and wind direction, covering the lower 48 states.
The data goes back to 1979 which allows you to check whether the wind speeds are changing in your location. Usually, the more recent years are most useful in determining suitability for a home wind turbine.
The limitations of this tool are that graphs are static, and lack the functionality of an interactive tool, meaning you cannot zoom in to find wind speeds at a specific location.
Also, maps are only available for wind speeds at 10m above surface level. If you live in an area where higher turbines are permitted then this database may not give you the information you need.
This is a free online tool that, as the name suggests, displays average wind speeds for virtually any location in the world.
You can quickly and easily zoom in the map to any area you like, or select a predefined area such as a state or country.
In the example above, I selected mean wind speeds at 10m above ground level throughout Texas. It works with any state, country, or even major road. There is also a search facility in case your geography isn’t the best and you’re not sure where to find a location on the map.
The raw data is downloadable with a few clicks. I also really like the fact that you can quickly switch to display wind speeds at different heights above surface level.
Tutorials are available to guide new users through the various features of this tool. I’m including the first one below so you can get a quick idea of what it looks like.
I find this to be the most useful wind speed database, and it’s completely free. So if you are considering a home wind turbine project I would recommend you take a look to get an idea of whether your location is suitable.
For the UK, there is an archived national wind speed database (known as NOABL - Numerical Objective Analysis Boundary Layer. The original source has been taken down but an archived version is available from the Department of Energy and Climate Change.
NOABL gives estimates of wind speeds at heights above the ground of 10, 20, and 45 meters It is based on the Ordnance Survey grid system and gives speed estimates at grid points 1 kilometer apart.
A postcode or any location on the UK map can also be converted to the nearest Ordnance Survey grid code using the conversion tool below. The resulting OS grid code was used directly as the position input to the windspeed database program (now superseded by the online wind speed database tools described on this page).
There is also an interactive real-time UK wind map provided by the MET Office. This gives current wind speeds and forecasts for the next 6 days.
The main limitation of the NOABL database is that its data was calculated on the basis of replacing the whole of the United Kingdom with a surface roughly equivalent to grassland and low hedgerow terrain.
In consequence, the wind estimates can be significantly in error in urban areas or rural areas with woods, high hedgerows, and numerous farm buildings.
It is important to stress that the calculations on which the database is constructed make use of the large-scale geographical topography of the area but not the detailed topography - particularly the man-made contribution to the topography.
In particular, it is difficult to get reliable estimates of wind speeds in urban areas because there is such variability in wind speed depending on the local building layout.
Speed estimates from the database are likely to greatly over-estimate the wind speeds in urban areas which are generally so low (i.e. typically 3 to 4 meters/second) that they are entirely unsuitable for wind turbine installations.
The flow of the natural wind over areas of high aerodynamic roughness is difficult to calculate but the Microgeneration Certificate Scheme provides a method for doing so, which gives a useful guide to the effect of local roughness.
After TheRoundup acquired the wind speed program website, we received several requests from readers who were disappointed that the authors were no longer selling and supporting the program and asking what alternatives were available.
Fortunately, time and technology have moved on, and the functionality that was once only available in a downloadable program can now be accessed freely online through your browser. Furthermore, the data now covers virtually the entire world, making it easy to access the vital data you need when deciding where (and whether) to position a new wind turbine.
The above suggestions serve as a starting point, but I fully recognize that the list is not exhaustive. If you know of any more good wind speed databases that deserve to be on this list, please get in touch and I will be pleased to review them.