One of the more expensive costs associated with adding a wind turbine to your home is the installation of the home wind turbine itself. It is therefore vital that you get its placement right first time. The cost implications of having to relocate it are going to impact heavily on the savings that you are expecting to gain from the project.
How Do the Experts Choose Where to Place a Wind Turbine?
The professionals when choosing the individual locations for each turbine on a wind farm spend huge sums on establishing whether or not a particular spot is optimal by creating wind maps over an extended period covering the entire area of the farm.
They do this by locating multiple anemometers (wind speed measurement devices) at various spots and various elevations around the wind farm location. The larger wind farm projects will use wind profile devices which can measure wind speeds simultaneously at multiple heights.
A typical wind profiler (a little on the large side for your back garden)
The data from each sensor is logged over a period of months. The sensors are then moved to other locations and the logging repeated. This process is repeated until the ideal placement and elevations for wind energy generation have been established.
Does this Matter for My Small Wind Generator?
Absolutely it does. You are looking to gain a long-term return from your generator in terms of reduced fuel bills over the coming years, over that sort of time scale the smallest change in average wind speed at one site over another will be significant.
What help is Available for the Home Wind Energy Turbine User?
You will doubtless have a number of possible sites and elevations in mind for the location of your generator but you need to choose the best spot and then the best height above that spot. You of course start with your prevailing wind direction, in the UK generally the prevailing wind direction is a south westerly but a further investigation of the Meteorlogical Office resources online is a good starting place . For example the wind data reported for here for the West of Scotland. Remember of course that wind direction reports the direction from which the wind is coming.
This is only the first step, the local effect on wind of landforms and structures (even distant ones) is something that is impossible to calculate it can only be discovered by trial and error. But when it comes to installing your wind turbine you want to get it right first time.
Ideally what you need is a means of measuring the wind speed without spending a great deal of money. This will pay dividends over the long term and also save the costly business of potentially relocating the turbine.
The cost of home weather stations has dropped over the years, they will provide a small easily mountable wind speed and direction sensor which connects to a central weather station display unit to give wind speed and direction displays.
Here are some of the characteristics to look for in a weather station for your home that will be ideal for the purposes of identifying the optimum location and elevation for your home wind energy generator:
- The wind speed and direction sensor should be wireless (all you have to do is mount the small and light sensor on a temporary pole, no hassle of running cables) and the sensor will communicate via a radio link with the central display.
- The display station should have the facility to download the recorded data to a computer (usually via a USB port). This will then allow you to analyse the data. Most home weather station manufacturers supply easy to use software to analyse the collected wind data.
The station that I used for the job was the Oregon WMR88.
The sensors supplied as standard with the WMR88 home weather station
It was not expensive and fulfilled the requirements listed above. Having said that there are plenty of others with similar specifications at around the same price.
I had three possible sites in mind and put the wind speed and direction sensor at each for a couple of weeks on a light plastic pole (which I simply tied with rope and tie-wraps to various local structures) . The sensor weighed a little over 100g and so was easy to place almost anywhere. Of course the longer that you can leave the sensor at each site the more representative of the overall exposure the data logged will be.
In the end this testing firmly demonstrated that one of my possible sites was not reliable, there was not much to choose between the other two.
Why Use a Home Wind Speed and Direction Sensor to Choose Your Home Wind Turbine Location?
A site that looks open and exposed may be subject to unexpected shading or funnelling from the local landform or structures a long way away. The only way to be sure is to measure the wind there objectively.
The cost and ease of carrying out this task make buying an inexpensive home weather station the ideal first step when planning to buy a home wind turbine.
