Air Pressure Sensors
Air pressure sensors (barometers) measure the air pressure. Air pressure and air temperature should be evaluated for an accurate wind site assessment, although this data could be obtained from nearby weather stations and thus they are not considered an essential part of a measuring system.
However, air pressure sensors are worth consideration, taking into account the savings made on the expense of supply, analysis and incorporation of external data over the course of a measuring campaign (at least 12 months).
Impact of Measurement Errors on AEP Calculation
Air pressure as well as air temperature significantly affect the AEP (Annual Energy Production). According to IEC 61400-12-1 air pressure has to be measured in a wind measurement campaign.
Wind power is linear proportional to air pressure. A measurement error of 1% in air pressure induces 1% error on AEP. IEC 61400-12-1 specifies the relations where the sensitivity factor for air pressure in the energy calculation is cB,i ≈ Pi / 1013 hPa.