Wind Potential - All About the Data

Wed, 2013-05-22 08:27

When it comes to the deployment of wind power, data plays an important role in the design and operations of a wind farm. Is there enough wind? Where should the turbines be placed? How will the placement of turbines impact performance? Are the turbines in need of maintenance? Data collected from technologically advanced monitoring devices answers these questions. Data analysis helps to advance wind power as a renewable energy source.

Met Tower

The initial planning of a wind farm begins with selection of the proper location, not surprisingly, where wind resources are abundant. Wind resource assessment is the process by which a developer estimates future energy production from a wind farm. Research often begins with maps published by government agencies. According to the U.S. Department of Energy, a desirable location will have an average wind speed of at least 9-10 mph. A preliminary site is then selected for on-site data collection. A meteorological tower (met tower) is installed to measure wind speed (with an anemometer), wind direction (using a weather vane), temperature, pressure, and relative humidity. Details, such as elevation and time of day, are factored in as well. Data from the met tower is collected for a minimum of about one year to determine the economic feasibility of a project.

Terrain Analysis and Wind Modeling

An in-depth analysis of the terrain on a possible wind farm site is performed using sophisticated digital elevation data and provides information for planning new infrastructure, calculations for prediction of wind conditions, and helping to minimize contact with bats and bird species. Aerial photography is coupled with digital elevation data to produce 3D visualizations, including line-of-sight perspectives to illustrate what the wind farm will look like from different viewpoints. Terrain data is also a primary input in software used to extrapolate wind climate statistics and create wind flow models to predict wind farm production and efficiency.

Performance Predictions

A recent study published in the Environmental Research Letters journal suggests that generating capacity of large-scale wind farms has historically been overestimated. The findings of the study assert that previous estimates ignored the slowing effect that multiple turbines have on the wind.

NREL scientists look at wind dataThis is not news to scientists at the National Renewable Energy Laboratory (NREL) who are already hard at work, improving the models used to make performance predictions and addressing the underperformance issue that has become an industry-wide concern. Scientists are working to maximize turbine performance, and the performance of the wind farm as a whole, through a better understanding of the impacts of turbulence from the wind, heating and cooling in the atmosphere, and interaction between multiple turbines. Using wind farm control systems, advanced technologies take into account the surrounding turbines and coordinate them to allow for maximum project efficiency.

According to Pat Moriarty of the National Wind Technology Center based at NREL, his team is using new data and tools to look at the wind farm as a total system, rather than just a collection of turbines. "Wind turbines are greedy," Moriarty said. "They will try to extract as much energy from the wind as possible without consideration for anything around them, such as other turbines in a wind farm. This is not necessarily the optimal way to operate a wind farm as a whole." Using wake models and airflow simulation, NREL scientists assert that a control system can be used to reconfigure a turbine’s orientation to let more wind pass through so that a stronger airflow hits downwind turbines.

Scientists at NREL are using data from operating wind farms to validate their new, more sophisticated models and simulations, underscoring the importance of ongoing data monitoring for wind projects.

Monitoring Wind Farm Operations

After the wind farm is constructed, data monitoring continues to be a critical element of the wind farm. The nerve center of the wind farm is the supervisory control and data acquisition (SCADA) system that connects individual turbines, the substation, the met tower, and bird and bat aviation radar to a central computer. The data allows the operator to diagnose problems, manage maintenance schedules, limit power output in response to instructions from grid operators, and take corrective action as needed. When a wind farm is not performing according to predictions and budget, data from the SCADA system is often used to determine if underperformance is due to mechanical problems or lower than expected wind resource.

Better Data, Better Performance

The analysis of data combined with new technological innovations, and a paradigm shift toward wind farm performance as a whole system, equates to growing potential for wind. Manufacturers, developers, operators, and power consumers stand to benefit from wind farms with improved performance, optimized energy capture, and reduced costs.

By Amy Malloy