How much energy will a wind farm produce?

Estimating how much energy a planned wind farm will produce – the so-called resource assessment – with as much accuracy as possible is vital to gaining financing for that project, but forecasting energy output is fraught with difficulty.

We spoke to Mike Anderson, Technical Director at RES, to unpick the issues.

What exactly is resource assessment?

Resource assessment is all about working out how much energy a site selected for a wind farm will produce. It is the process of using available climatological and topographical data to calculate, with minimised uncertainty, the potential energy produced within a site considered for development. The process of undertaking a resource assessment is complex and involves skill and judgement coupled with a firm understanding of numerical models.

Why is it important and who is interested in it?

The economics of a wind farm project are crucially dependent on the wind resource at a site. A robust estimate of the energy production of a prospective wind farm based on a wind and energy assessment is essential in supporting investment and financing decisions for both developers and investors. The more accurate the resource assessment, the more trust financiers will have in wind energy and therefore the greater the likelihood is of gaining finance for a project. Conversely, if assessments made by wind farm project developers differ greatly from the reality, financiers are likely to ask questions. That is why it’s important to work together as an industry to try and improve resource assessment as much as we can – essentially good techniques can improve our access to finance. In June EWEA is holding a technology workshop tasked with delving deeper in to resource assessment, if you’d like to know more, click here.

EWEA has launched a new exercise on resource assessment, what’s it all about?

Participants are invited to analyse and report the net energy yield for a 22 turbine wind farm. All the input information required for the assessment – from wind patterns to land relief on the actual site -, including instructions and guidelines on how to report results, are provided in a data pack which can be downloaded from the EWEA website.  The exercise is expected to attract a high number of participants, whose results will form the basis for an insightful analysis into the range and variation of site assessment results obtained from the wide spread of organisations involved. Click here to download the exercise.

In 2011, a similar exercise based on a theoretical wind farm attracted participants from 36 organisations. This year the exercise builds on its predecessor by providing a wider range of inputs, including roughness and obstacle information, and it is based on a real wind farm. Participants will be able to see just how accurate their resource assessments are.

Why might I be interested in attending the workshop?

This is a unique opportunity to compare your own resource assessment techniques against those of others from across the industry, as well as to discuss ways of improving resource assessment. Results from the assessment are analysed independently and compared anonymously. What is more, the workshop is taking place in the prestigious setting of Trinity College, Dublin, and includes a tour and tasting at the Old Jameson Distillery, Dublin!

Find out more on the workshop here.



By Zoë Casey,