RPS enters a new era of support for our sustainable energy future

Floating LiDAR: the modern standard for wind resource measurement

Driven by the growing global demand for renewable energy, over the past decade, we’ve seen a steep rise in the deployments of floating LiDAR to support offshore wind farm development. This technology, which was a game changer when first introduced, provides robust data on the vertical wind speed and direction profile using light detection and ranging technology deployed on a moored buoy.

Traditionally, these measurements were made from meteorological (met) masts that were fixed to the ocean floor equipped with instruments called cup anemometers to measure wind profiles at sea. With the increasing uptake of floating LiDAR, there’s been a massive shift away from using met masts for the measurement of wind resource data.

According to RPS’ MetOcean Australian General Manager, Greg Bush, this shift towards floating LiDAR is driven partly by cost, the increasing height of turbines requiring higher wind data that is difficult for mast based measurements, and increased demand for accurate, reliable data from the burgeoning offshore wind farm industry.

“An upward facing laser can measure wind speed characteristics up to 300 metres above the instrument. Whereas met masts are limited to capturing data at around 120 metres. Erecting a met mast offshore is also much more costly, especially as wind turbines are getting higher and higher. Offshore met masts can cost tens of millions to install, whereas you can deploy a buoy for around 10-20% of the cost. Unlike met masts, LiDAR buoys can easily be moved to different locations.”

“Floating LiDAR assists wind farm developers by providing them with a wind profile by measuring the mean wind speed and direction every ten minutes for an entire year. This enables them to do wind energy return calculations before they have spent millions of dollars putting turbines in the air. It also helps them capture the shear in the wind, which is a measure that compares the strength of the wind, at say, 30 metres versus 100 metres.” 

New trends and improvements in floating LiDAR

Since RPS launched its fleet of floating LiDAR in 2018, there’s been major improvements in satellite communication systems to enable the extraction of large volumes of data in real time. Within about a minute, the buoys are now able to report a collection of metocean data from wherever they are deployed in the world.

Greg says RPS is continuously modernising their data communications through technology upgrades and field proofing.

“Our job is to provide the LiDAR with a steady offshore platform, dependable power supply, consistent data logging, and robust satellite communications to get all that valuable data out of it.”

“Our LiDAR buoys have proven highly reliable, in part due to a split system that provides redundancy in data logger, communications, and power systems. It means if we have a failure on one system, we’ve still got the other one as a back-up.”

In addition to those changes, RPS’ LiDAR Survey Manager, Michael Wiegele says the buoys are now also easier to maintain.

“We’re always across the latest technologies, so we’ve reduced in field maintenance times that might be required.”

“We’ve got a good reputation for producing robust buoys that supports the sensor. You are out in the ocean with big waves, and you can have panels getting crashed, wind generators falling over, and boats running into the buoy – despite all of that, RPS is able to capture great data. That comes back to our decades of experience of metocean buoy manufacturing and deployment. We build robust buoys and have an effective mooring design.”

“Our designs have been successful in withstanding some of the toughest conditions. In fact, we’ve weathered some incredible storms, including nearly 20 m high waves in the North Sea and freezing temperatures well below zero Celsius off the coast of New York,” he adds. 

While the primary purpose of the buoys is to measure the wind profile, Greg says the technology is also used to measure and monitor other factors.

“Because the engineers involved in developing wind farms require a range of data, we’ve been integrating other sensors into the buoys. So, we’re also measuring waves, currents, tides, temperatures, solar radiation, barometric atmospheric pressure, rainfall, and so on. We’ve done extensive validation on these.”

“We’ve even had requests to monitor birds and bats, and other environmental observations. And some companies have asked us to trial a 360-degree buoy camera to monitor fishing boats that get too close to a buoy at times.  And while we do not measure underwater noise from the buoys, we can install separate moorings to acquire this important environmental data.”

Reaching stage 3 maturity: the highest commercial maturity level

Another significant change has been the achievement of stage 3 certification of the RPS LiDAR buoys. This recognition means that when it comes to accuracy, reliability, and quality of the data collected, RPS LiDAR buoys have met or exceeded key performance indicators (KPIs) that have been set out in the Carbon Trust roadmap. This is the pinnacle industry standard devised by a conglomeration of industry players to ensure bankable data is collected for offshore wind projects.

According to Michael, RPS was able to reach this level of certification at an impressive rate.

“We started building custom-designed LiDAR buoys around 2018, so it only took us five years to gather the required data and project experience, which means RPS achieved this industry standard really rapidly.”

One of the major milestones to become stage 3 certified, says Michael, came down to the number of deployments.

“In our first four years, we’d completed the five 12-month commercial campaigns with great data returns, required to meet the Carbon Trust roadmap KPIs for stage 3.”

Aside from being a clear stamp of approval for accuracy and reliability, Greg says this certification is what financial institutions are now looking to when greenlighting the funding of wind farm projects.

“Banks take a great deal of interest in the wind energy measurements because basically the source of that energy is going to pay for everything. So, it’s becoming critical for wind farm developers to work with a certified company like RPS.”

“We have reached the point where we are now starting to see the very first tenders where you are only qualified to bid on the project if you have been granted a stage 3 certification.” 

The importance of local validation sites

Under the Carbon Trust roadmap, the commercial acceptance of floating LiDAR is dependent on every buoy built having a validation deployment. That means to ensure trust in data from floating LiDAR, there needs to be a comparison to another trusted reference source such as a compliant met mast or a fixed LiDAR. Essentially, it’s an independent assessment and analysis of how accurate your data is compared to the trusted reference.

Greg says that most wind energy experts prefer the validations to be conducted local to the wind farm area.

“If you’re going to measure in Australia, its preferable to validate buoys in Australian waters rather than overseas where the atmospheric conditions can be very different.”

In line with this, RPS has a fixed LiDAR installed on a platform located in the Gippsland wind farm declared area, which extends from Melbourne’s eastern suburbs to the New South Wales border. Data from here can be used to complete a unit validation of LiDAR buoys to be deployed in South-eastern Australia.

“We’re hoping to leave the LiDAR at this location for up to 10 years to create a long data set; to quantify interannual variability. This will capture one of the uncertainties in the wind recourse assessment for the Gippsland area,” explains Greg.

The fixed LiDAR will be used to measure wind turbulence intensity (TI), which is the measure of variation of wind calculated at 10-minute intervals.

“Our clients require TI data to assist in specifying wind generators and predicting maintenance. Wind farm developers prefer steady wind and low turbulence intensity, as variable winds accelerate fatigue.” 

“Essentially, we’re offering a validation site in the Gippsland region, open to all operators and buoy suppliers.”

Australian-made: the benefits of local LiDAR buoy production

RPS’ custom-designed floating LiDAR buoys have led the way in a new era of precision and dependability when it comes to capturing accurate and reliable wind speed data. This Australian-made and engineered design has been manufactured using high standards set out by Australia’s health and safety, environmental, and labour laws. 

There are further advantages to an engineered design that is associated with the green and gold. Greg says the local support model is an undeniable benefit.

“Our buoys are built in Perth – all our welding, electronic components, and the entire build is done locally in Western Australia. So, if there are any problems within Australian shores, we've got a whole team of technical, logistical, and manufacturing experts who can jump in and fix anything that happens to a buoy. RPS builds the only LiDAR buoy manufactured in Australia, and from a government perspective this gives us an additional tick of approval, as they are very keen on locally produced content.”

“The other advantage with us being in Australia is rapid mobilisation. We can transport a buoy on a train to Gippsland within a week.” 

Since 1974, RPS has provided highly specialised commercial metocean services to all major offshore industries worldwide. So, 50 years of experience and an outstanding track record in safety and quality has helped shape RPS’ LiDAR buoy designs.

“We’ve poured all the lessons that we’ve learnt over five decades into this design, to be able to increase reliability and accuracy of data.”

An indispensable tool for wind farm development

Accurate wind resource assessments are the cornerstone of wind farm development, which makes RPS’ floating LiDAR an essential instrument. Greg says data from floating LiDAR is critical to the assessment of offshore wind farm viability.

“You don’t want to build a wind farm and discover the winds aren’t very strong. RPS’ floating LiDAR measurements allows wind farms to be developed with confidence. That’s the key, and it’s allowing reliable, cost-effective, and high-quality measurements anywhere.”

As the attention on wanting to meet ambitious net zero targets becomes laser-focussed, Greg says another new trend is emerging, which presents an opportunity for RPS floating LiDAR.

“What we’re seeing now is a strong push towards floating wind farms. Originally, wind farms were in less than 50 metres of water, and they were piled into the seabed. Essentially, that’s just a tower sitting in the seabed that supports the wind generators and turbines.”

“Now, there’s a push towards floating technology, where dozens of different designs are proposed to support the wind turbines in deeper water. That means wind developers are now also needing wind measurements in 1,000 metres or more of water. Floating LiDAR is the only feasible solution in these water depths, where our deep-water metocean experience is also vital.”   

RPS floating LiDAR: a snapshot of key features

RPS’ commercial deployments of floating LiDAR so far span the UK, Korea, Netherlands, USA, Poland, and Australia.

Some key features of RPS’ sophisticated LiDAR buoy design include: 

•    Positioning of the LiDAR unit – our LiDAR equipment is positioned high off the water (3 m) and protected from all sides and underneath.
•    Simple and renewable power – the power system we designed is all renewable. This is not only good from an environmental perspective, but makes permitting much simpler, particularly in countries like the United States.
•    Data protection – one of the risks when you deploy buoys offshore is that of data loss when connection to the satellite or power source is disrupted in some way. Our buoys have redundancy mechanisms in place for power and satellite communications and all raw data is stored locally and exported daily, meaning the risk of data loss is significantly reduced.
•    Increased stability – a lot of thought went into the physical design of the buoys to enhance stability. The buoys are large (weighing 4T) and have a toroidal (donut) shape, which provides a very stable platform for housing the LiDAR and other metocean sensors.
•    Environmentally friendly moorings –the fully recoverable mooring system we’ve designed also supports high quality wave measurement and does not drag chains on the seabed. This means that the risk of environmental damage is minimised.