Wind Resource Assessments

Fundamental to any wind development is measuring the available wind resource on site to ensure that the predicted energy production and therefore revenue from the proposed medium-wind project is accurate.  It is good practice to measure the wind at the exact location of the proposed medium-wind turbine and at or close to the proposed turbine hub height.  We can provide masts from 30 to 70 metres high, depending on the size of medium-wind turbine required.

We recommend applying for permission to erect the anemometry mast during the early WP2 planning stage so that the mast can be erected and the data collection started as soon as possible.  The minimum recommended period for monitoring is twelve months, though we provide a quarterly ‘summary’ analysis of the data which can be seasonally adjusted to provide reassurance that the expected wind resource is available at the site.

In addition to the basic measurement of windspeed, we use multiple anemometers at different heights to accurately calculate the wind-shear so that the increase in windspeed with increasing tower height can be accurately estimated.  Wind direction data is recorded to enable optimum positioning of the wind turbine in relation to local geographical features and/or other proposed wind turbines to ensure that wake influences on energy capture are minimised.  We also calculate turbulence intensity which shows how ‘smooth’ the airflow is at the site and is becoming increasingly important to ensure that wind turbine manufacturer’s warranties are valid.  For larger projects we monitor pressure and air temperature so air density corrections can be made.  Rain gauges are also supplied for use during the background noise measurements which are generally required to support the planning application.

We only use the highest-quality calibrated Vector anemometers and wind vanes.  All data is stored on a solar-powered data-logger with battery back-up to ensure that the batteries never run out and valuable data is lost.  We use GSM modem-enabled loggers which email the raw data direct to our offices every night, so unnecessary trips to site to download the data are avoided.

The masts use concreteless ground anchors to hold the guy-wires in position and are normally installed in a single day.  Once removed a year later and there is no permanent trace left.  Masts also come with lightning protection to ensure that damage is minimised in the event of a strike.

Masts are rented on a quarterly basis with a fixed installation and decommissioning charge.  The quarterly charge includes all of the data processing and analysis.

The data is presented as an industry-standard Weibull distribution and wind rose and calculations to show the annual mean windspeed, turbulence intensity and wind shear parameters.  Further analysis can be done, including Measure-Correlate-Predict (MCP) and siting optimisation, which is particularly important for multiple-turbine projects.