User:Trobomono/sandbox

= Executive summary =

Wind Energy in Cold Climates (CC) refers to sites that may experience frequent icing events, temperatures below the operational limits of standard wind turbines (WT), or both. Apart from lower energy production, which directly influences a wind farm’s cash flow, liability issues, such as ice throw and increased noise, may raise development risks. Additionally, one needs to consider fatigue loading and operation and maintenance (O&#x26;M) aspects particular to CC. WT operating in cold climates are located around the world, including sites in Asia, North and South America, Europe and even in Africa.

 Resource assessment with respect to icing  – Icing maps are useful as first source of information for assessing icing related risks. More detailed, site specific meteorological modelling can reveal more information about site icing conditions and related safety and financial risks but model validation is critically important. CC sites also have additional requirements for wind resource measurements and often require special sensors. The influence of ice on or near the sensors will decrease data coverage and increase the uncertainty of measurements.

 Ice detection  - Dedicated and reliable ice detectors are useful for measuring ice effects for a planned wind farm on safety (ice throw) and potentially reduced energy yield and for turbine control purposes in operational wind farms. For ice effects to safety and energy yield, the occurrence of ice (yes/no), icing intensity (kg/m/h), type of ice (rime, glace) and ice load (kg/m) are useful inputs for analyses. Specific turbine ice detection solutions are available for turbine control and controlling active ice protection systems.

 Ice models  – Modelling of ice accretion is important to estimate the impacts of ice on objects. Advanced models are used for detailed assessment of ice type and shape for aerodynamic analyses whereas simplified ice accretion models are used to estimate icing rate and mass on objects typically in weather model applications. Ice removal models are very important for wind energy but are relatively immature compared to ice accretion knowledge.

 Cold Climate adaptations for wind turbines  – Special low temperature adaptions are needed for turbine materials, lubricants, heating etc. to ensure safe and efficient operation. Ice accumulation on turbine blades can be mitigated with blade ice protection systems and many technological solutions exist on the market from both turbine manufacturers and independent 3rd party system providers. Dedicated turbine control features for turbines with ice are also needed.

 Assessment of ice throw and ice fall  – During the approval phase of a project, the risk of ice throw and ice fall has to be assessed. In some areas, the use of empiric formulas that give a rough indication of the maximum throw distance is sufficient. However, in many cases, authorities may demand detailed risk assessments that take into account the local icing conditions and the likelihood of people in the danger zone. Mitigation measures like warning signs and flashing lights are widely used to lower the actual risk levels.

 Operation and maintenance  – The risk of ice injuring service staff or the general public must be taken very seriously in icing climates. Road and turbine access for maintenance staff in areas with significant snow fall can prove to be a challenge. Icing forecasts can improve O&#x26;M planning.

 Standards and certification  – Standards are needed to have the same baseline and minimum requirements for all actors in the industry from turbine design to site ice assessment. Icing and cold climate related standards exist for modelling ice, defining ice induced loads for turbines, and characterizing offshore sea ice effects. Certification practices typically follow existing standards.

 Testing  – The testing of new designs and innovations for cold climate regions is an essential part of a product development cycle. Dedicated test facilities have been set-up for CC with climate chambers and icing wind tunnels for testing small products like sensors, and large components like gearboxes or even fully installed wind turbine assemblies.

''' Further needs for technology research and innovation ''' – Low temperature and icing introduces special challenges for wind energy and many technology areas need further research and new innovations (R&#x26;I). In order to streamline and focus new R&#x26;I efforts nationally and internationally, Task 19 proposes a prioritized list of research and innovation needs for the cold climate wind energy community. Top 3 topics for near future R&#x26;I are:

'' Standards, certification and recommended practices ''

'' Assessment of reduced production prior to deployment, financial risks and uncertainties ''

'' Ice protection systems, equipment and procedures ''

