The lidar concepts come from the fact that in the 80s riders were quite bulky and difficult to operate. And because they were emerging market for measuring atmospheric environment, we thought that it was possible to compact the lidars and make it easy to use. On the compass there are a lot of research centers dedicated to environmental monitoring and scientific studies, such as CEA Litmus, L MD ONERA. So all the ingredients were there to build a new technology, a new scientific point of view on lidars. And at this time the telecom markets were blooming. A lot of companies were developing lasers, detectors, fibers and putting all these together. It was possible to build a new product based on these telecom components. The chance we had is that the lasers used in telecoms can be pursed and so could be used for lidars. And the other chance was that the wavelengths that is currently used in fiber transmissions Is 1.5 is exactly a good wave length to be transmitted in the atmosphere. And so we had the technology we ask the scientific background and we could build a new lidar family. In the late 90s I hired two PhD students, one working on the hardware of the lighter and one working on the software and together they built the first lidar based on telecom technology. It was quite huge. A room was needed to close the lidar. But we had the first results at this time. Then we decided to compact the lidars and to put the lasers and detectors, the telescope into racks. And lidar was about one meter cube of size. But it was the first time that we put the outside, Leo Sphere was founded in 2004 by Alexander and Lauren Savage. Their first idea was to develop lie thus for aerosol monitoring. And in 2006 ONERA transferred the technology of client wind lidars and because of the quick growth of wind energy, we were able to develop and build and sell our first writers within two years. So in 2007 we sold our first lighters and in 2010 and with lidars were operating around the world. The sliders, the windcube lidars were used to assists the wind on new sites for new wind farms and because the leaders were able to replace the mast, a lot of customers used them and in 2016, more than $750 are now operating around the world. Here is the wind cube, the star doppler wind lidar of aero sphere. Thanks to its five laser beams. These virtual met math measures the recent tool on vertical wind speed and direction from 40 meters to 290 meters. Once the turbines are installed, a national leader can be an attractive alternative. Here is our wind iris based on the same measurement principles but looking horizontally. The wind iris unfavorably replace the wind cube offshore farms or on onshore complexity rain to get more information from different wind directions. The lidar can be used at any stage of the wind farm life for reducing uncertainties through accurate wind and turbulence measurements. First for wind resource assessment, during the project development, then for power performance testing during the commissioning and finally during operation, through performance monitoring and optimization of wind turbines. Wind cube is an accurate as mast with a cub or sonic animators provides wind data at 10 attitudes simultaneously and ensures more than 95% of data availability at 150 m. What the valves, a whistle. The lidar can withstand harsh conditions from minus 30° to plus 45° and can actually be installed anywhere here, for example, is an installation in Sweden by areas UK, renewable energy provider. The wind cube demonstrates low consumption of only 45 watts. Allowing the lidar to being supplied by fuel cell or solar panel for at least three months. Here is the image of a wind cube that was deployed by The Danish Consultant Alpha Wind in the desert of Saudi Arabia for 12 months period in Europe. So in CUBA is used mainly by wind developers and consultants to measure the wind profile at different places on the future wind farm of a full season and to derive the wind speed statistics in other markets like USA and China we see a stronger focus on performance testing in an oppression or used by asset managers. For example, as you can see on the top graphic horizontal wind speed is measured at a given height and plotted versus time during three hours showing the different time scales. The statistic analysis of this time series confirm the weber distribution of the wind speed instagram. Let me explain the interests of lidar in wind resource assessment. Amid mass is usually 60 or 80 meters high corresponding to smart turbines up height. So consultants need to extrapolate vertical horizontal wind to estimate it over the full disk of the rotor. As turbines grow higher and bigger, it's even worse and the wind up right cannot be measured directly. The exasperation leads to more uncertainty in AEP estimation. The lidar range covers the full disk of next generation been turbines either future six to ten MW. Moreover, the lidar doesn't need any collaboration while cup enumerators on the veins need a yearly calibration. Of course the trust ability to current practices is often required. That is why lighthouse unmasked are currently used together. But what is AEP? The AEP is Annual Energy Production, assuming 100 present to buy availability. It represents an estimate of the total energy production of a wind turbine during a one year period. As calculated by applying the measure turbine power curve to a rally frequency distribution at the specified bite annual average wind speed. With again of 40% on AEP uncertainty and by the advantage of instrument mobility, the return on investment of lidar is only 1.5 years. It also brings strong reduction of total cost of ownership. The mast is fixed, lidar is light, small and can be easily deployed on site, especially on complexer range. On the large future wind farm has sewn on the right then possible to move the lidar collecting data at different points and during different seasons and finally, to reduce the uncertainty due to the horizontal exasperation of the wind profile. The lidar is not the only remote sensor used for wind energy. So sodar is an alternative using sonic waves instead of light waves. Even though cheaper and more energy efficient. The sodar is less accurate than the lidar, bigger in size, more sensitive to ambient noise and so cannot be installed close to mass or buildings because of its large beams. Moreover, so there needs a temperature correction on the post processing filtering. Lidar signal relies on back scatter on natural aerosols and it is then proportional to the concentration of particles, but the extinction is also proportional to this concentration. So when fog occurs, maximum range is then limited because of aerosol extinction. On the contrary, that availability can be reduced in very clear air conditions such as arctic atmosphere. Because of the low aerosol concentration, fortunately 95% of atmospheric conditions give good wind speed measurements. The lidar availability is totally insensitive to bright sunshine to distant clouds and rainy conditions don't affect horizontal wind measurements. On the top figure lidar wind data and kept data are plotted together and time series are very close to each other. This good coalition is unchanged during the reign periods. However, concerning vertical wind speeds, the bottom plot shows large vertical speed during the winter period coming from echoes on falling droplets. And flat terrains the wind flow is assumed to be parallel to the ground above 40 meters. So when reconstruction is accurate and the bias between the lighter on the mass is lower than 1%. As you can see with these graphics, the comparison plot between wind speed measured by capital meters on by leaders at 99 meters height is a perfect straight line, which unitary slope. And complexity terrains such in Greece the flow lines are not reasonable and simple reconstruction algorithms don't perform well with the bias from 3-7%. However, assumptions on terrain profile and roughness can be taken into account in efficient embedded algorithms. To finally strongly reduce the velocity uncertainty from 6% down to 1% as you can see on the figure on the bottom right. Thank you for your attention. [MUSIC]
