The competing technologies both distinct advantages and limitations, renewable energy consultancy Dulas claimed in its Enhanced Data and Enhanced Returns report.
Accurately assessing a site’s available wind resource is crucial to maximising the performance and profits of a wind farm.
Historically, met masts fitted with measurement devices have been used to collect this information.
But with the emergence of remote sensing technology such as Lidar (light detection and ranging) and Sodar (sonic detection and ranging), some OEMs are looking to completely replace the use of met masts with remote sensing devices.
However, Dulas argued specific conditions pertaining to a site, such as accessibility or ground conditions, must be considered when choosing which technology to deploy.
Strengths and weaknesses
The consultancy also argued each technology has its own strengths and weaknesses.
Met masts are seen as the industry standard and many lenders unfamiliar with remote sensing devices will only accept data from the former, Dulas claimed. Maintenance is also quicker and easier, the consultancy added.
However, they also capture less data overall than remote sensing devices, are less easily deployed, often require planning permission, are not particularly versatile and can be expensive.
Remote sensing units, meanwhile, are becoming gradually more accepted.
They can measure data at greater heights, offer a wide range and depth of measurement data, can account for wind shear, giving a more comprehensive understanding of wind conditions, are verdsatile, and can be installed quickly and easily without need for permits, Dulas argued.
However, many lenders will not accept data from remote sensing devices, threatening the financial viability of a project.
Remote sensing devises also may require security solutions to ensure they are not tampered with, stolen or damaged, their data readings can be affected by severe weather and atmospheric factors, and they require a power source to run.
Specific site conditions
Selecting and deploying the correct wind monitoring technology for a specific site will reduce the margin for error and enhance project returns, Dulas argued.
The consultancy added the height for which measurements are required, site accessibility, ground conditions and the local environment must be considered.
Using met masts for a project with hub heights that greatly exceed the height of the met masts will force developers to extrapolate the data collected, for example.
It might also be difficult to deploy met masts at sites that are harder to access, Dulas argued.
However, in complex terrain, airflow distortion can make it difficult to guarantee the accuracy of data collected by remote sensing devices, the consultancy suggested.
Dulas’ commercial director Alistair Marsden, said: "Too often the decision to favour either met masts or remote sensing devices is made in isolation, far from the sites where they will actually be deployed.
"As a result, it’s easy to overlook issues such as the site’s accessibility, ground conditions, or difficult terrain — all of which can cause a project to incur additional and unforeseen costs and delays.
"Developers and investors must therefore bear in mind that the choice between met masts and remote sensing units is not a zero-sum game.
"Both have a role to play in an integrated approach to wind resource assessment that factors the technology, site conditions and project timeline and resource budgets into the decision-making process."
The UK-based consultancy suggested that, if technically and financially viable, using both technology types may help to eliminate uncertainty.