"High confidence in the `climatological' wind patterns can dramatically reduce economical risks"

Wind Energy Performance Optimisation Special

For a company, which has worked on an advanced research and modelling community with a focus on extremely high resolution, Storm Weather Center says it can offer the end-user operational model runs down to a resolution of 25 metres.

Storm runs its MM5 model on a daily basis for over 30 different regions around the world.According to the company, wind prognoses with higher resolutions give improved accuracy compared with traditional prognoses from resolutions between 4 and 20 km.
Storms modelling group also focuses on extreme high resolutions down to 25 m in addition to the operational applications. Such high resolutions are normally utilised in numerical modelling, but also in mathematical/statistical post- and pre-processing of high-resolution model-data. Caliberation and post-processing of model-data can give considerably improved quality to wind, temperature, precipitation prognoses.

Overall, the industry is witnessing progress on several counts. For instance, in terms of forecasting the wind power production, a major focus has been on actual meteorological wind prediction, with efforts largely based on precipitation and temperature, with a lower resolution than one relevant for wind power.

On how this has changed, Dr. Gard Hauge, modelling manager, Storm Weather Centre, says: "The last decade has seen tremendous development in increased `computerpower'. This has lead to a rapid development on the forecasting systems used by weather companies and governmental institutions. The real-time prediction systems are now focusing on horizontal scales down to a few hundred meters with a targeted time window specified uniquely for a given wind farm. In my opinion, the way to go is targeted model set-ups at 1km resolution which are specially adjusted and designed for maximum performance of a given park."

Dr. Hauge, who is scheduled to speak during windenergyupdate.com's Wind Energy Performance Optimisation Summit (to be held on 11th - 12th February 2009 in Hamburg, Germany), spoke about use of detailed wind predictions for more accurate short term energy trading, the role of meteorological services and much more.

Excerpts:
windenergyupdate.com: Can you provide an insight into how to use detailed wind predictions for more accurate short term energy trading?

Dr. Gard Hauge: Wind predictions are very challenging in complex terrain due to large variations between land, sea and topographic variations. By increasing the horizontal and vertical resolution in a weather prediction model, these variations are much better resolved by the modelling systems. Running operational numerical weather prediction models several times a day, worked from global scale models to 1 km resolution, gives the best possible wind predictions on the 0-48 hour time window.

Limited area models such as the Weather Research and Forecast model, WRF, used by Storm is a model designed for these purposes. This and other similar models strongly depend on the quality of the boundary data used and the large scale weather phenomenas are accurately described by the global scale models. Inaccuracy in the boundaries represents one of the biggest challenges for accurate wind predictions in the short term.

Accurate high resolution wind forecasts can be extensively used to create unique predictions for each wind turbine within a wind park. This gives much higher skill on the total energy production estimates than just by applying a single point when calculating the energy production.

Model results can be dramatically improved in the short term, i.e. from 0-12 hours ahead based on real-time statistical corrections of the model results. This is done by real-time correction of estimated winds every hour with a coupled system between observations from each turbine within a wind park and the model data presented.
Such improved skill will of course maximise the profit possible to gain within a wind park.

windenergyupdate.com: The role of meteorological services is increasingly gaining significance in the wind energy industry. Such information is being used  during the various stages of wind farm projects, be it for site evaluation, construction or operations. Meteorologists have several techniques in their arsenal. How do you think such services are being used as of today?

Dr. Gard Hauge: To my knowledge the meteorological services play a cruical role in the planning of wind farm projects. High confidence in the `climatological' wind patterns for each site can dramatically reduce economical risks when building a wind park.

windenergyupdate.com: What according to you is critical when it comes to analysing wind data, ocean currents and patterns from  meteorological departments? How do you think companies need to related wind resource and the economic viability of the project from meteorological department perspective?

Dr. Gard Hauge: I think it is critical to look at the background model and data used from the meteorological departments and have a strong focus on verification of the results they are presenting. It is also of vital improtance to look at case specific events and not only on averaged values over time.

windenergyupdate.com: From an operational perspective, planners and managers of wind farms need a continuous feed of reliable information concerning forthcoming conditions. How do you assess the availability of a detailed site specific hazard alerts for lightning, heavy rain, icy access roads, fog, snow and heavy rain to safeguard turbines, to assist with maintenance planning and repair work, and fulfil health and safety requirements?

Dr. Gard Hauge: By using weather prediction models in combination with meteorologists, hazardous weather could be reasonably well predicted. Some of this can be made automatically but has to be controlled by trained meteorologists for the best possible result.

windenergyupdate.com: Both weather and risk are a numbers game and by marrying the two, the level of risk can be brought down significantly. Just about all aspects of a weather forecast can be given a numerical value which makes it a very useful tool when considering risk. Warning thresholds can be set on all of our forecast parameters allowing assessors to assign a level of risk to any particular part of a project. Do you agree with this?

Dr. Gard Hauge: To some extent yes, but numerical models all have their deficiencies. The uncertainty of situations is always useful to have in combination with "absolutes".

Wind Energy Performance Optimisation Summit

Dr. Gard Hauge, modelling manager, Storm Weather Centre is scheduled to speak during windenergyupdate.com's Wind Energy Performance Optimisation Summit (to be held on 11th - 12th February 2009 in Hamburg, Germany).

For more information, click here: http://www.windenergyupdate.com/performance09/programme.shtml

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contact Tom Evans by email: tom@windenergyupdate.com