Having undertaken many successful lifts for both the construction and maintenance of wind farm projects in the country, the company was recently appointed by Azari Wind (Azari) as cranage contractor on Enel Green Power’s 111 MW Gibson Bay Wind Farm in the Eastern Cape, South Africa. Azari is the crane and installation contractor appointed by Nordex Energy South Africa (Nordex), the EPC contractor on this €190-million project.
Lifting the tower section
Johnson Crane Hire’s Brandon Grange considers this contract to be a significant milestone for the company in its growing reference in wind farm projects.
Before being awarded the contract, Johnson Crane Hire underwent a two day internal audit by Nordex and Azari. “Our compliance with ISO 9001 certification standards played a very big role in us being awarded this contract,” he says.
Tower section installation underway.
“Our working policies were put to the test. Nordex and Azari wanted to ensure that we comply with their exacting standards in every way possible, including being in line with Azari’s ISO 9001, ISO 14001 and OHSAS 18001 requirements. As a major player in international wind farm projects, we knew that their approval of our processes would only further cement our progress in this specialised heavy lifting market,” Grange says.
Installation of the nacelle.
The lifts started early in May, following a three month preparation period that included the involvement of all of the engineers working on the project. Here, the details of the lift including assessments of the wind speeds and ground-pressure bearings, were finalized.
Lifting the blade.
“Every site comes with its own very complex set of challenges which is why we spend so much time preparing for each lift. It is one of the key differentiators Johnson Crane Hire brings to this industry,” says Grange.
Over a five month period, Johnson Crane Hire will lift the various components of the 37 wind generators making up this wind farm. Having already supplied lifting services for about 80 wind turbines, Johnson Crane Hire has a solid understanding of the complexities of these super lifts.
The lifts for each wind turbine include four tower sections (50 to 60 tons each), a nacelle (55 tons), drive train (62.3 tons), hub (35 tons) and three blades (11.2 tons and 57 metres in length each).
Johnson Crane Hire undertook the lifts in accordance with Nordex and Azari’s predetermined schedule, and while all components had to be handled with extreme care, Grange says the enormous blades are extremely sensitive. A damaged component could delay the successful delivery of the project and impact on its cost.
One of the challenges is the very windy conditions in which the lifts are being undertaken. This project is situated close to the coast and, as such, the construction site experiences significant wind speeds. At about 06h00, wind speeds range from between three to five metres per second and up to nine metres per second by midday. By the time Johnson Crane Hire lifts the hub and blades, wind speeds could have reached 15 metres per second or more resulting in unwanted difficulties.
This is the first time that Johnson Crane Hire will be undertaking tandem lifts for the blades. On earlier projects, these were all done in single lifts.
He says that the professional team considers the extra crane a major boon in areas with high wind speeds where lifting schedules are accelerated as it does save costs. “Those extra hours saved make all the difference,” says Grange.
Again, this lifting project will feature a strong Liebherr fleet of cranes. One of Johnson Crane Hire’s competitive edges is its massive fleet of new cranes from this German original equipment manufacturer.
“Not only do they design and manufacture the best cranes on the market, we receive excellent back-up service from them,” he says.
On this project, the lifting specialist is using an Liebherr 750-ton LG 1750 crawler crane fitted with 245 t of counterweights. Once the hub is in place, this lead crane is joined by an Liebherr 400-ton LTM 1400-7.1 mobile crane to help lift the blades. The LTM 1400-7.1 is fitted with a 42 metre Fixed Fly extension to boost its 60 metre reach.
One of the company’s ongoing success stories is its skilled crane operators. The LG 1750 and LTM 1400-7.1 will be operated by Johnson Crane Hire personnel with a combined experience of almost 40 years in super lifts.
They are joined by Johnson Crane Hire’s experienced crane crew. “Members of these teams are extremely knowledgeable about both the machines and the environments in which they are performing. Their first consideration is safety, and they will never allow a lift to proceed unless this mandate has been met,” Grange tells Plant Equipment & Hire.
The cranes are kept in immaculate condition by Johnson Crane Hire’s facility in Cape Town and national workshop. They are serviced every 500 hours. At these intervals, the booms and ropes are greased and the safe-load indicators on all of its cranes calibrated.
The LTM 1400-7.1 is also used to assemble and erect the LG 1750. For the stripping and installation of the cranes, Johnson Crane Hire is using a Liebherr LTM 1095-5.1 crane.
Depending on the terrain, it takes between one to three days to relocate the cranes to the different pads where the lifts are being undertaken in line with Azari’s policy on this project which is to minimise transport and maximise lifting movements on site. This project site spans at least four private farms, with each pad located about 400 metre from the next.
The LG 1750 was bought specifically by Johnson Crane Hire for lifting wind turbine components, and it has been involved in many of the these projects under the South African government’s very successful Renewable Energy Independent Power Producer Procurement (REIPPP) programme.
“An advantage offered by this machine is that it is narrow and travels on tyres, as opposed to tracks. It is also fitted with folding outriggers, improving its mobility on roads,” says Grange.
All of the other cranes were mobilised from Johnson Crane Hire’s yard in Johannesburg, travelling between 50 km to 60 km an hour to the site. One of the biggest challenges here was working around the embargoes during the March/April holiday period.
Johnson Crane Hire’s knowledge also helped save costs on the project by eliminating the use of crusher run for the construction of some of the 37 auxiliary pads for the LG 1750. Here, excavation and compaction methods were deployed to achieve the 20 ton per square metre ground-pressure bearings needed to support the lead crane, saving Nordex and Azari in costs associated with backfilling with aggregates.
This was the case on four of these 12 metre by 15 metre pads which were located on steep inclines, and needed to be aligned with the others.
Meanwhile, Johnson Crane Hire was awarded a contract for two cranes by Absolute Rigging, which has been sub-contracted by Nordex and is under Azari’s installation management.
Johnson Crane Hire’s Liebherr LTM 1160-2 and LTM 1095-5.1 place the various components in the storage areas when they arrive on site. They are deployed again when they lift and place these components in the laydown areas around the LG 1750 before it starts lifting. They are transported by two multi-axle trailers to the various pads. The entire process is co-ordinated with Azari’s lifting schedule.
Increased local participation in government’s REIPPP programme is growing. Johnson Crane Hire is proving that it is able to compete against the best the world has to offer when it comes to complex super lifts!
