Fuel-agnostic and suitable for newbuilds and retrofit, Organic Rankine Cycle waste heat recovery systems are making headway as an energy-efficiency measure.
Market prospects are looking so good for waste heat recovery systems that Orcan Energy recently expanded its industry relationships by partnering with Goltens on installations.
Andreas Sichert, CEO of Orcan Energy, said: “Waste heat recovery is one of the most powerful and underutilized tools for improving energy efficiency. In shipping alone, over 100 TWhth of waste heat could be harnessed.” This is equivalent to the power consumed by more than 6.3 million people.
Over half of the energy from fuel consumed by ships’ combustion engines is lost as waste heat via exhaust gases or cooling circuits such as jacket cooling, scavenge air, or lubrication oil. Around 50% of this waste heat is available as low-temperature heat (below 100°C), which can be captured by Organic Rankine Cycle (ORC) waste heat recovery systems. These systems use organic fluids to drive turbines that convert low-temperature thermal energy into electricity. This offers a simpler and more compact solution that the steam turbines used in other waste heat recovery systems.
Image courtesy of Orcan Energy
Jonah van Sluijs, Marine Sales and Business Development Manager at Orcan Energy, says retrofits are gaining momentum and newbuilds are increasingly being designed with waste heat recovery in mind. Standardized interfaces and reserved space at the shipyard level make integration simpler from day one.
He highlights some of the company’s recent technology developments:
Modular ORC-based waste heat recovery packages have been introduced designed for retrofit in constrained engine rooms with skid or split-skid options.
Multi-source heat harvesting is now possible, combining exhaust economizers, high- and low-temperature jacket water, steam systems via economizers, and thermal oil systems into a single power module.
Hybrid integration blocks with shaft generators or batteries allow operators to prioritize recovered energy where it offsets the most expensive kWh on board.
Image courtesy Climeon
Together with higher-temperature modules, the Orcan Energy ePM200 XR enables the recovery of energy across a wide temperature range and operational profile, capturing value both at high-load cruising and lower-load conditions. The ePM200 XR is a new lower-temperature waste heat recovery unit optimized for moderate-temperature sources, such as jacket water or auxiliary cooling loops (80–120°C). It delivers up to ~200 kW net electrical output, ideal for vessels with limited exhaust heat or those operating at part load or slow steaming.Yes, slow steaming does impact shipowners’ decisions on adopting waste heat recovery, says van Sluijs. “At reduced engine loads, there is less exhaust and system heat available, so the net output from traditional waste heat recovery modules is lower than at full load. To address this, shipowners are increasingly adopting a portfolio approach: combining high-temperature recovery modules on the exhaust, steam, or thermal oil side with lower-temperature units, like the ePM200 XR, on hot water loops. This ensures meaningful energy recovery even at partial loads.”
Modern ORC controls further optimize performance dynamically, keeping modules online and efficient across varying operating conditions. As a result, owners can maintain compliance with efficiency and emissions regulations, capture OPEX and CO₂ savings, and reduce reliance on slow steaming without sacrificing operational flexibility, says van Sluijs.
Waste heat recovery partners well with new fuels such as methanol. System manufacturer Climeon foresees the already favorable payback period for its ORC waste heat recovery system as potentially being cut in half by 2030.
Image courtesy of Orcan Energy
“Vessels operating on alternative marine fuels typically offer a more favorable waste heat profile for ORC systems compared to those running on HFO,” says Fredrik Thoren, executive vice president, head of marine sales at Climeon. “For example, methanol-fueled vessels often require less auxiliary heating, such as tank heating, which means more waste heat is available for recovery. In many cases, this allows the Climeon HeatPower 300 to generate more electricity.
“Additionally, methanol engines often produce lower exhaust gas temperatures. HeatPower 300 can operate effectively using only the jacket water or high-temperature cooling water, without the need for an added steam boost, making it particularly well-suited for vessels without excess steam.”
In June, Climeon received a repeat order from NovaAlgoma Cement Carriers (NACC) to supply its HeatPower 300 waste heat recovery system for a second cement carrier. The new 38,000-ton vessel will be the world’s largest cement carrier powered by renewable methanol and is expected to reduce CO₂ emissions by more than 60% compared to conventional vessels due to the green technologies it features.
And in September, Jiangsu New Yangzi Shipbuilding selected Climeon’s HeatPower 300 system for a new series of methanol dual-fuel container ships. Climeon’s HeatPower 300 units are already operational on three of six 17,200 TEU methanol-fueled container ships being built by HD Hyundai Heavy Industries for Maersk, Climeon’s first large-scale newbuild project.
Vessels that operate on higher speed/higher engine load and with fewer other heat consumers on board will have more available waste heat and will benefit the most from an ORC retrofit installation. Operation in colder sea water temperatures will also increase power output from the ORC.
Whether multiple Climeon units are installed depends on the ship’s design and operational profile. An example case would be a RoPax vessel with a 4-stroke engine having total engine capacity around 30MW, operating primarily in colder climates and at high speeds — maintaining an average main engine load above 60%. Under these conditions, a significant and consistent amount of waste heat is available, making the installation of multiple HeatPower 300 units a practical way to maximize energy recovery and cost savings, says Thoren.
In the case of a 180,000 GT cruise ship with a main engine power of 85MW and two HeatPower 300 units, fuel savings could be 480 tonnes/year if the ship is in operation 6,500 hours primarily in seawater temperatures between 20 and 30oC.
Thoren says that the system is best suited for retrofit on vessels younger than 15 years, but there is no technical limit related to the age of the ship. Based on the current product portfolio, Climeon’s addressable market includes approximately 30% of the 1,500–1,800 new vessels built each year. In addition, an estimated 8 to 10% of the roughly 110,000 vessels over 100 gross tons in the existing global fleet are considered suitable, based on age and size, for retrofit of Climeon’s technology.