In an article for Renewable Energy Focus Stuart Thomas discusses how Unmanned Aerial Vehicles (UAV) are helping wind farm operators dramatically lower their costs and improve the safety of workers.
“A step improvement in the planning and maintenance of on- and off-shore wind farms is happening with the aid of technology led services by specialist operators. This is particularly evident with the rapid evolution of Unmanned Aerial Vehicles (UAV) and Remotely Operated Aerial Vehicles (ROAV). The services provided by experienced land surveyors and inspection engineers combined with skilled pilots and these small flying vehicles is providing dramatic cost savings and improvements in safety to the renewables industry.
This article covers land surveying services using UAVs to improve the planning and monitoring of the construction of new projects and inspection services using ROAVs to improve the maintenance of assets once operational.
The quality of geospatial information is at the heart of all planning and design for any new renewables development. Accurate and reliable topographic survey information is vital – from scoping right through to design and construction. Good visual data of a location can really improve not only the project team’s understanding of the site, but also the team’s decision-making process.
Traditional land surveying methods are very labour intensive, requiring the surveyor to cover every inch of a site in order to take observations using GPS or total station instruments. This process can be very time-consuming, with a surveyor covering 5-10 hectares in a day depending on site conditions — which can be highly challenging. Renewable projects and their related infrastructure are often situated in hostile environments (hilltops, moorlands, remote valleys, cliffs and tidal areas), so when a survey lasts for several weeks, the exposure to risk at such sites can be significant and protracted.
In the last few years, UAVs have been developed to acquire high-resolution aerial imagery. Recent advances in battery technology, miniature autopilot systems and digital cameras have allowed the development of robust and compact unmanned systems suitable to acquire commercial-quality aerial imagery.
In the renewables sector, UAVs are used to acquire high-resolution aerial imagery and process the results using advanced photogrammetry software to generate accurate topographic survey information, orthophotos and oblique panoramic images. This advanced technology has revolutionised the acquisition of site data at these often remote sites.
UAV-acquired information is highly beneficial for assessing potential site locations, designing site layouts, generating 3D visualisations, assessing site visibility, calculating earthworks volumes, monitoring construction progress and producing as-built records.
Benefits of UAV surveys
Small UAVs, operated by experienced and skilled professionals, can provide a step improvement in survey data collection. The accuracy of the survey information derived by UAV is in the region of 100mm vertically and 50mm horizontally, depending on the required resolution of the images and the number of ground control points. This resolution is sufficient for most renewable projects.
Up-to-date UAV digital images are also beneficial to a project because online resources such as Google Maps are, typically, out of date and of very low resolution at the remote sites where renewable projects are frequently situated.
A UAV can easily survey more than 100 hectares in a single day. This means that the survey can be much more cost-effective than traditional land surveying, with the additional benefit of high-resolution imagery. A UAV survey team needs only limited ground access during the survey, which reduces the exposure to risk and the ability to survey hostile environments.
Following are some of the main benefits of a UAV survey when compared to a traditional land survey:
- UAVs are more cost-effective
- The site work can be carried out more quickly
- There is reduced exposure to risk for surveyors
- Limited ground access is required on site
- Inaccessible/hazardous areas can be surveyed remotely
- UAVs offer in improved data – topographical information plus high-resolution aerial imagery
Inspection using ROAV
ROAVs have been utilised for onshore and offshore inspection services in the oil and gas and utility industries in the UK, Europe, Asia and the Middle East. With more than 200 flare inspections and over 1500 transmission tower inspections completed over the last few years, this inspection solution is now becoming established as best practice in these industries. This technique is now being applied in the renewables industry with the inspection of structures such as wind turbine blades and met masts.”
For the full article click here.