Allseas pioneers in offshore energy market as well as sustainability

Traditional installation design gives way to innovative 2-way system

Allseas is a leading global contractor in the offshore energy market. The company specializes in the design and execution of large and complex offshore projects in four areas: pipeline installation, heavy lifting, deepwater manganese nodule gathering and river waste capture. "Our core business is installing oil and gas pipelines on the seabed," says Sustainability Engineer Taco Straathof. "Ever since our founding in 1985, we have been actively pioneering to enable pioneering changes in the offshore energy market. This started in 1985 with pipelaying with propellers instead of traditional anchors. Eleven years later, we even built the largest pipelaying vessel in the world; with pipelaying records unbroken to this day. In 2015, Pioneering Spirit was launched; a giant ship 382 m long and 124 m wide that can lift offshore platforms in one go. In early July, this lifted a platform weighing more than 31,000 tons in one go! In the future, we even want to lift platforms of up to 60,000 tons. This makes Allseas unique in the market, which also applies to our focus on sustainability."

'Dare to pioneer'. This slogan of Allseas refers not only to the large projects, but also to smaller initiatives such as making its ships more sustainable. "The implementation of the Belimo Energy Valve™ in our climate control systems fits perfectly with this," says Straathof. "Whereas a standard container ship carries 12 to 16 people, our ships employ on average some 200 to 500 people for whom we want to achieve optimal climate conditions. In this context, the Energy Valve had been on my radar for quite some time. Not only because this control device gives control over the amount of water actually flowing through our systems, but also because it collects useful data on plant performance. About 1.5 years ago, this product suddenly became topical in the improvement and sustainability of the air conditioning system on our pipeline vessel Lorelay; a versatile vessel for executing small and medium diameter pipeline projects in unlimited water depths."

Moving away from the traditional setup

"I came into contact with Taco Straathof through one of our account managers," says Dirk Bijlaart, Manager of Technical Advice at Belimo. "Already in our first conversation we went into engineering, with several colleagues joining to share their knowledge. Through a principle diagram, I gained insight into the systems on the ships, based on which the first ideas for efficiency improvements emerged. In particular with regard to the way cold was dispensed. With our RetroFIT+ approach, we moved away from the traditional setup in shipping, where continuity is paramount." Straathof: "In shipping, energy was never an issue. Reliability always prevailed. However, with the climate challenges we face, reliability and sustainability are now aligned."

Sustainability and expansion

"In the old situation, cold water was continuously pumped around at full load," he says. "Moreover, the amount of water was designed for the worst possible conditions. Consider, for example, the high humidity in Malaysia or the high outside air temperature in Australia, which require a lot of cooling. When the same ship is in the North Sea six months later, this wastes (too) much energy. For the new situation, we were happy to see this change. Moreover, a great desire was to expand the air conditioning system on Lorelay by approximately 30%, without having to rigorously tackle the cold water system. Full visibility and control over where the water flows was necessary for this."

From constant to variable flow rate

Lorelay - like Allseas' other ships - until recently had a statically controlled 3-way system with constant flow. "When you want to add more consumers, you have to manually restore the balance," Straathof knows. "In this case you have to measure how much water flows at each consumer and adjust the static balancing valves, bearing in mind that the flows affect each other." In consultation with Allseas, the 3-way system was optimized and adapted to a 2-way system with Belimo Energy Valves™, says Bijlaart. "An important condition for this RetroFIT+ improvement was that the pump that pumps the water around could be controlled using a variable speed drive. This is what Taco and his colleagues did very well and energetically." In the new situation, Lorelay's air conditioning is controlled on a pressure basis, with 2-way Belimo Energy Valves™ controlling the water to the consumers. "The moment the consumers need less water, the pump also has to run less hard," Bijlaart illustrates .  

"Compared to the old full-load situation, this has greatly reduced the pressure differential." Straathof: "We have already gone from 60 to 45 hertz, which is a significant electricity savings." When the pressure differential decreases, power consumption decreases proportionally to the power of 3.

Both 3rd and 4th generation Belimo Energy Valves™ were used at Lorelay. "With the Belimo Energy Valves™, Allseas can specify per consumer the maximum amount of water that can flow to it," Bijlaart said. "In addition, Allseas gains insight into useful data such as power and supply temperature, return temperature and temperature differences, based on which usage and settings can be optimized." This greatly benefits the efficiency of the chillers, according to Straathof. "In addition, the Delta-T has been increased, to a guaranteed Delta-T of 5°C or higher."

RetroFIT+ optimization on Sandpiper

"Thanks to the new 2-way system, Lorelay's crew can now decide which chillers to turn on for each location and circumstance," Straathof says. "If the ship is near the Wadden Sea, a small installation is sufficient, while in Mexico, for example, two large chillers can be switched on." Lorelay's RetroFIT+ optimization will be completed in October 2023. "Parallel to this project, we also tackled Sandpiper; a flat-bottomed anchored barge for shallow-water offshore installation activities, which was purchased and upgraded by us in 2022. Here we stayed away from the traditional 3-way constant flow valves and directly installed a 2-way injection system with Belimo Energy Valves™ at all consumers connected to the cold water system. The cold water system is laid out as a closed ring system, allowing us to easily add and remove consumers now and in the future."

Flow control valves for Pioneering Spirit

Meanwhile, a third (large) project has also begun on Pioneering Spirit, working with a central cooling water system to which numerous devices can transfer their heat. This heat is then cooled away with seawater. "This system is also traditionally designed, based on full load and worst-case conditions," Straathof says. "In the plant there are eight pumps of 150 kW each, with three or four of them running at standard. Regardless of whether heat is being delivered or not. The Belimo Energy Valves™ are deployed here as dynamic flow control valves that - when our Pioneering Spirit is not 100% operational - save some 300 kW of energy per hour. Every day and all year round. We have now received the green light from our management to order 160 Belimo Energy Valves™. This brings the total number of Belimo Energy Valves™ in Pioneering Spirit to 174 for one system."

17 Belimo Energy Valves™ have been installed on Lorelay and 20 on Sandpiper, and Audacia, on which 8 Energy Valves will soon follow, says Straathof. "In addition, 10 Energy Valves are currently being installed on Fortitude."