Vaisala Validates Accuracy of Wind Assessment Methodology

Study demonstrates calibration of Vaisala's wind due diligence approach with operational wind farm production data

Vaisala, a global leader in environmental and industrial measurement, has performed an extensive validation, confirming the accuracy of its unique, state-of-the-art energy assessment methodology. The results of this assessment validation process have revealed that, on average, the wind projects in the validation study performed within 0.1% of Vaisala's pre-construction estimates during the years analyzed.

Vaisala Wind Assessment Validation Histogram

This statistic is based on a comprehensive analysis of 30 operational wind farms, totaling 127 wind farm years. Of the years encompassed by the study, 90% were between 2010 and 2015, providing a significant sample size while still ensuring that projects' measurement techniques were up to modern standards. The result confirms that Vaisala's calculations are calibrated and in line with P50 wind energy estimates.

For the last decade, underperformance has been a key concern of the wind industry and investigations have revealed that more sophisticated assessment methods are required to improve pre-construction energy estimates during the due diligence phase.

While Vaisala's approach to energy assessment follows many standard best practices familiar to the industry, it has also introduced several new innovations. For example, Vaisala pioneered the broad integration of NWP (numerical weather prediction) models into the wind resource assessment process and works with ensembles of all the leading global reanalysis datasets to more accurately characterize the impacts of climate and weather at a project.

The company also relies on full time series data rather than averaged quantities to more realistically show the influence of unusual weather patterns. In addition, it has developed a next generation uncertainty model known as the Energy Risk Framework, which captures risk at every step in the assessment process, incorporating complex dependencies ignored in classical approaches.

"Our techniques move the industry forward by addressing shortfalls in the standard approach. The advantage of using next generation methods like NWP modeling has already been demonstrated in recent industry validation studies," said Matthew Hendrickson, Global Manager of Energy Assessment at Vaisala. "The transparency of our method and how we communicate risk makes our science accessible to clients, building confidence and trust. As a responsible player in the industry, we felt it critical to validate our methods and answer the simple question: how well did we predict actual plant production?"

With advantages in both modeling technique and risk characterization, Vaisala has gained respect with a number of global banks and investors, increasingly becoming their preferred choice. Today, the company is in regular outreach with key investors, and is working towards universal acceptance of its approach.

Hendrickson added, "While these results are encouraging, this study is only the first cycle of a perpetual feedback loop. As technology evolves and greater sophistication is required, this ongoing validation process ensures Vaisala continues to lead the industry with cutting edge science while maintaining an accurate and calibrated wind assessment process."

Vaisala is an expert in wind measurement, project assessment, and energy forecasting. For more information on the range of services offered by Vaisala to the renewable energy sector, visit

Featured Product



The addition of energy storage to an existing or new utility-scale PV installation allows system owners and operators the opportunity to capture additional revenues. Traditional storage plus solar applications have involved the coupling of independent storage and PV inverters at an AC bus or the use of multi-input hybrid inverters. An alternative approach - coupling energy storage to PV arrays with a DC-to-DC converter - can help maximize production and profits for existing and new utility-scale installations. DC-Coupled Utility-Scale Solar Plus Storage leads to higher round-trip efficiencies and lower cost of integration with existing PV arrays and at the same time, opens up new revenue streams not possible with traditional AC-coupled storage, including clipping recapture and low voltage harvesting, while being eligible for valuable tax incentives.