Publishers version - DTU Orbit

7. A recent study by Rogers et al. (2012) analysed a variety of scenarios that could be
addressed by turbine mounted lidar, including retrofitting lidar to existing turbines, larger
rotors and taller towers. Benefits of turbine mounted lidar included a 6 year life extension
and 30% increase in total energy production (when a lidar was retrofitted to a 2.5 MW
turbine); an increase in permitted rotor area of 6% and an associated energy output
increase of 4% (larger rotor on 5 MW turbine); a 3% energy output increase from a
greater allowable tower height, achieved through reduced fatigue loads (again on a 5
MW turbine). The same study also estimated an achievable increase in energy output
due to optimisation of lidar control alone to be just 0.6%.
Clearly, turbine mounted lidars have an important role to play in reducing costs of energy
generated by wind turbines. This application is discussed in more detail and in broader scope
in other lectures.
Acknowledgements
The authors are grateful for the support and enthusiasm of their colleagues and collaborators.
Without them, wind power lidar technology could not have evolved to its current advanced
state.
Notation
a floating parameter for the fit of the line-of-sight velocity
A beam radius at the output lens
ADC analogue-to-digital converter
b floating parameter for the fit of the line-of-sight velocity
B wind bearing
c speed of light
floating parameter for the fit of the line-of-sight velocity
CFD computational fluid dynamics
CLR coherent laser radar
CNR carrier-to-noise ratio
CW continuous wave
DFT digital Fourier transform
D(ν) power spectral density from dark noise
ELO LO field
Es stable signal field
FFT fast Fourier transform
FPGA field-programmable gate array
h Planck constant
i fluctuating detector power output
IR infrared
LO local oscillator
m slope of the linear regression
Ps time-average optical signal power
PT transmitted laser power
R distance of the beam focus from the lidar output lens
R2 coefficient of determination
RIN laser relative intensive noise
D(ν power spectral density from RIN
SNR signal-to-noise ratio
t time variable
TI turbulence intensity
TKE turbulent kinetic energy
u wind speed component in the x-direction
v wind speed component in the y-direction
VAD velocity-azimuth-display
VH horizontal wind speed
VLOS line-of-sight wind speed
w wind speed component in the z-direction
100 DTU Wind Energy-E-Report-0029(EN)