Observation technology
•Data logger: Vaisala QML201L •Temperature sensor: Pentronic Pt-100•Humidity sensor:Vaisala HMP35/45 humidity probes•Pressure sensor: Vaisala PTB220 barometers•Cup anemometer: Vaisala WAA151, 251 and 252 •Vind Vane: Vaisala WAV151, 251 and 252•Thies Ultrasonic 2D wind sensors•Data transfer: TC543 telecontroller GSM/GPRS
Wind: Energy measurement and analysis services in FMI
by Jenni Latikka, Jani Gustafsson
Email: [email protected], [email protected]
Introduction
The Finnish Meteorological Institute has long-standing and internationally recognized experience in studies related to wind energy, e.g. definition of local windiness and icing and effects of global climate change to wind energy production.
The Finnish Meteorological Institute performs wind measurement and analysis services from the clients' desired sites. Measurements and analyses draw from the vast research & development expertise of the FMI. The FMI has holistic know-how on wind studies, thus enabling turnkey projects.
Wind measurements
The standard measurement system for wind energy predictions are for example 90 m high measuring mast. The mast is equipped with five ore more wind sensors installed in three different heights (30m-60m-90m) on the mast.
Temperature, pressure and humidity measurements are also needed when calculating wind energy predictions.
Measurement data is recorded for each sensor with a ten minute averaging period.
The system measures:
•Mean wind speed, direction and deviation
•Wind gust
•Air Temperature and pressure
•Relative humidity
•The measurement data is collected from data logger in 10 min using GPRS connection.
•The quality of the data is controlled with FMI´s quality control system.
Production system
A typical delivery contains the inspection of technical and meteorological properties of the measurement site, delivery of measurement equipment with installation including support structures, commissioning of the measurement system, quality control of measurements, maintenance, wind observation data relay and analysis to the customer and disassembly of the equipment at the end of the measurement campaign
Analysis
Local wind field analyses can be derived from wind measurements, from Finnish Wind Atlas (2009), from numerical weather prediction models or wind measurements from the upper atmosphere. The height of the boundary layer and stability of the air mass is taken into consideration in the wind analyses.
Data correction
Measured data have to check before local wind field analysis to minimize errors due to used raw data. Data checking and correction includes e.g. accuracy definition, inacccuraties removing, time-series unifying, calculation of basic quantities and filling in the missing values.
Representativeness of measuring period can be rated by wind index which based on correlation of short and long time series.
Comparison to Wind Atlas
Measured wind speed and direction as well as results of local wind analyses can be compared to Finnish Wind Atlas (2009).
In Finnish Wind Atlas (2009) you can find amog others annual mean wind speed for grid point with 2.5 km horizontal resolution. Wind Atlas results can be focused with micro-scale model and produced detailed wind resource map.
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