Technical requirements for lifting equipment in power generation applications have changed little over the decades. Safe and secure movement of heavyweight items has always been key to assembly and well as maintenance in such an environment. However, new technologies are nonetheless having an impact on safety and reliability, writes David Appleyard
Power stations are replete with equipment built on a massive scale.
The huge boiler feedwater pumps, enormous steam turbines and gigantic generators found within a typical coal-fired or nuclear power station all require lifting into position during construction, as well as partial disassembly for maintenance and even removal for major refurbishment.
Undertaking such a challenge, where items are bulky, could weigh hundreds of tonnes and are often awkwardly shaped, asymmetrical and off balance, is just that – a challenge. But it’s a challenge that any power station must address many, many times over a 30- or even 50-year lifespan. Indeed, large hydropower installations may have a lifespan measured not in decades, but centuries.
With heavy lifting a relatively frequent operation in such an environment, it’s not surprising to see a suitably robust gantry crane stretching across the turbine hall of many power plants. However, not all installations have the necessary lifting equipment and, even where they do, the crane is often at least as old as the equipment it is used to maintain.
Crane maintenance is therefore a critical element in ensuring overall plant reliability.
“The industry will tell you they barely use the cranes, and then they’re waking up and realizing that this equipment is 80 years old,” says Mike Brown, Director of Business Development for Finland-headquartered Konecranes, which last year announced an all stock merger with Terex Corp.
“Over their lifespan, we’re finding fatigue-like cracks. After 80 years of intermittent use it’s accumulated. The parts are not on the shelf, they have to be reverse-engineered, and we have to bring them up to today’s standards.”
Such an endeavour is naturally costly and time-consuming and may warrant complete replacement of the lifting equipment. However, this may not be economically or technically achievable. “We look at the feasibility. In a lot of the hydro plants it’s difficult to replace the crane, they’re in remote areas,” notes Brown.
But he nonetheless sees a clear trend for refurbishment of existing hydropower assets and, with it, increasing demands on lifting equipment.
“We’re seeing a trend in the hydro plants first off, because of the green energy. A lot of companies have to make sure that their hydro plants are up to speed, there’s a lot of retrofitting of equipment in the hydro facilities, so companies want to make sure that those cranes are up to speed because they’re re-building the turbines or re-building the equipment at these hydro plants.
“The industry trend is that they’re going with more technologically advanced [lifting] equipment,” Brown continues. “A lot of power plants in the Americas and Canada are very old, and the cranes that were there at the time have very antiquated technologies in them. They go up, down, left and right. Today what customers want and need is precision loading of the technology that allows anti-sway, so that there is no swinging of the load. There’s very precise load scale on the cranes now so that they can measure the load, and there are positioning tools that allow operators to put the hook directly centre in a very precise spot over the turbine.”
“There may be some upgrading of the electrical controls, to give more precision. Mechanically it’s the same crane, but electrically we put the latest technologies on it for that precise spotting.”
While, with the older cranes, this type of operation was done by lining up ‘by eye’, Brown explains that the move to more precise load and location assessment has grown significantly.
Lifting for Alstom Power in Karlsruhe, Germany
“It started in the last decade, but it’s really become a standard in the last five years. The value for the client is that it decreases the amount of time for setting up of the crane. It can save a couple of days having this technology, which pays for itself 10 times over.”
“They are going from a very, what I would say, limited technology to state-of-the-art technology almost overnight in these facilities.”
Monitoring and safety
While more accurate monitoring and positioning can save time and therefore money, safety is absolutely critical in the heavy lift environment and new remote monitoring technologies have a role to play here too, as Jeroen Naalden, Director at Enerpac Integrated Solutions, explains: “Safety drives innovation. A safe working environment is very important. We use more wireless controls to not have cables and hoses laying around.”
Naalden adds: “We are not yet working with cameras in our equipment, but I can see that coming as well. You can monitor the loads per leg, what you’re lifting, that’s already what you can read out from our remote control systems and they’re wireless.”
An emphasis on safety is a point echoed by Brown: “Another technology we’re putting on is remote monitoring, so companies can tell if they’re overloading [the crane] and how it’s being used – especially at remote locations, where there is only a handful of people at a power plant. We still have dropped loads and accidents happen with cranes. Remote monitoring systems, retrofitting is the wave of the future. Ten years from now all cranes will have this technology.”
TRUCONNECT, the trade name for Konecranes’ remote monitoring systems, was launched in mid-2011. Based on a remote connection, the system collects usage data from the crane and compiles it into a report with the history data of the crane and important crane-specific key figures in real time. By recording overloads, emergency stops and other issues, safety is improved, the company says.
In North America, safety is a big driver for investment in lifting equipment. “For those markets it’s driving the decision. Anything that can improve safety and reliability is more important than the equipment cost right now,” says Brown.
Smarter, lighter cranes
Where new lifting equipment is being installed in existing power plants, new crane design philosophies and techniques can be explored. As Brown notes: “We’re going with lighter cranes in the system. This helps with building loads and, in some cases, we are able to increase the capacity of the crane. We can reduce the dead load.” That weight difference can be transferred into lifting capacity.
Another example comes from Enerpac. Positioning of heavy loads is frequently carried out using more than one crane, but synchronizing movements between multiple cranes can be difficult and creates an increased risk of damage to the load and support structures.
In a bid to address this problem, in December last year the firm announced the launch of its SHAS-Series Autonomous SyncHoist system for precision load manoeuvring with a single crane. Deployed below-the-hook, SyncHoist comprises four independent, self-contained PLC-controlled hydraulic lifting cylinders with up to a 225-tonne lifting capacity each. In addition to synchronous lifting and lowering, the operator is able to lift and lower each cylinder independently for balancing, tilting and positioning loads.
Good old-fashioned maintenance
New technologies, designs and techniques are evolving, but there is little to substitute a considered maintenance programme for power station lifting equipment and many crane OEM suppliers offer long-term maintenance contracts as part of their service offering.
As Brown explains: “We try and make the entire crane maintenance as minimal as possible, so there’s wheel bearings, automatic adjusting breaks, all things that a power plant would need to do maintenance on – and frankly they’re not very good at it, because the crane is ‘out of sight, out of mind’.”
He adds: “One process we put in place, especially for older cranes, is inspection and repair work six months prior to an outage. We ensure that the crane is inspected and any issues are taken care of, so that when an outage starts they have a well-working crane.
Installing test piles, Wikinger offshore wind farm
Credit: SAL Heavy Lift
“When there’s an engineering lift which is slightly over the crane capacity, that inspection we take even a step further in what’s called a pre-engineering mode inspection. These are quite common now when upgrading the [power plant] equipment, as the new equipment is heavier than the old.”
MTS Vanquish towing a shipment of wind turbine foundations
Naalden argues that operators and owners could reduce the demands on heavy lift equipment by designing power plants with appropriate long-term consideration of the plant layout. “The people who built those plants have not always focused on maintenance needs, especially older facilities,” he says.
He cites an example in which a generator located on the ground floor of a power block had to be lifted over another building on the site for refurbishment. Such an operation may require bespoke equipment to achieve: “We made a lift and skidding system with flexible hydraulic cylinders to move it. The generator weighs 240 tonnes and is approximately six metres high. We moved it over the four metre-high building and positioned it on ground level outside the generator hall for maintenance.”
Offshore heavy lifting
The energy business is a global one and a significant proportion of OEM equipment is transported by sea. Another key driver in offshore heavy lift technology comes from renewable energies such as wind and tidal.
Steve Bendell, Commercial Manager at the MTS Group Ltd, explains: “There are a number of specialist vessel types designed to meet the needs of the power sector. These range from crane and jack-up barges to massive heavy lift ships that can bear the weight of an entire rig or offshore substation.
“In the offshore energy sector, the move into deeper waters has increased the demands placed on vessel operators and their fleets. The further from shore, the harder it is to use jack-up vessels or deploy anchors to maintain position during heavy lift operations. Increasingly, tug and towage operators like MTS are seeing demand from the energy sector for anchor handling work to assist with this challenge.
“Larger barges and vessels are increasingly being fitted with Dynamic Positioning (DP) systems. These enable vessels to automatically hold a position and heading in deeper waters than can be achieved by jack-ups and boats fitted with traditional anchors.”
This is a point echoed by Sune Thorleifsson, Head of Project Department at SAL Heavy Lift GmbH. He says: “We believe that we offer as high a standard of safety as you can get in the industry, but precision as well is a key factor.”
Thorleifsson continues: “We have DP vessels which have proven to be very cost-effective in terms of time in the installation. They can be mobilized within a very short time and, with their operational speed of up to 20 knots, we are able to use even the shortest weather windows.”
Indeed, Bilfinger chose SAL Heavy Lift as subcontractor to transport and install the test piles and equipment with their DP Class 2 vessel MV Lone for the Wikinger offshore wind farm project on the Baltic Sea. MV Lone has 2000 mà‚² of clear main deck, two 1000-tonne SWL cranes and an operational speed of 20 knots.
Looking at the future market for heavy lift equipment, Bendell highlights the offshore renewables sector, particularly in Europe: “Offshore wind will undoubtedly be a key market for European heavy lift businesses in the next few years.
Construction is set to ramp up again in late 2016 and early 2017 as UK Round 3 projects kick off, and there is also movement in the new French sector. Naturally, there is no shortage of applications for heavy lift vessels, jack-ups and cranes on these sites.
“The tidal sector is likewise showing signs of potential growth. Should a project like the Swansea Bay Tidal Lagoon get the go-ahead, transporting and installing tidal turbines will require specialist heavy lift expertise.” Thorleifsson also picks up on this: “The offshore wind sector is one which is interesting.It’s a heavy, big component which needs to be installed, especially in the UK,” he says.
Turning onshore, Bendell sees new nuclear capacity increasing the demand for marine heavy lifting assets. “Large pre-manufactured components such as transformers are difficult to transport via land, and typically are delivered by barge – often necessitating complex beach or riverbank landings. In addition, both the offshore and onshore construction of interconnection and subsea cabling projects generates a lot of business for marine firms involved in heavy lift operations.”
He adds: “MTS recently towed a specialist barge carrying nine transformers from Rotterdam up to Hunterston in Scotland for the Western Link interconnector project and, as these kinds of projects proliferate, it’s set to be a growing market.
“With the aforementioned growth in offshore renewables, Northern Europe is set to remain a core market for specialist vessel operators over the next decade.”
Naalden also sees considerable opportunities in the Middle East and North Africa, as well as elsewhere in the developing world: “A lot of what we sell is going to the emerging markets.” He highlights Nigeria, Egypt, Dubai and India as examples.
Thorleifsson echoes: “Egypt and emerging countries. We can also see prospects in Africa, not only North Africa but also East Africa.”
And Bendell adds: “Another interesting market where we’re increasingly seeing movement is West Africa, where a number of large energy infrastructure projects are in the pipeline.”
Power generation equipment is evidently getting bigger and heavier, whilst changing operational and maintenance requirements are increasing demands on power station heavy lift equipment. While the handling of such substantial items remains largely unchanged from the earliest days of the power generation industry, it’s a whole lot smarter – and therefore safer.
David Appleyard is a freelance journalist and editor focused on the energy and technology sectors