To achieve increasing emission requirements, the cruise ship industry is working to develop higher efficiency ships. Cruise ships are different from other ship types in their relatively higher consumption of electrical power, steam and hot water. Several novel high-efficiency system concepts are possible for on-board electrical power generation and other utility services, each with differing impacts and first costs. Low-emission concepts novel to the cruise ship industry include combinations of exhaust gas heat recovery, heat pumps, steam turbines and organic Rankine cycles (ORCs). Yet, evaluation of these concepts is difficult given the different operating modes of cruises, and overall efficiency is dependent on the dynamic operational sequences. In this paper, we compare alternative energy efficiency concepts for cruise ships through simulation studies of the ship operations when equipped with different novel power generation systems. We find that the dual pressure steam systems and ORC offer the greatest potential for energy efficiency improvements in the cruise ship industry. We also find that relatively conventional technologies enable cruise ships to comply with planned upcoming higher ship energy efficiency requirements.

This paper contributes to existing research on energy flexibility by introducing centralised and decentralised model-predictive control (MPC) strategies designed to deliver demand reductions over specific time periods for demand response based on real-time demand projections. The MPC strategies were evaluated with co-simulations of an English community fitted with heat pumps over three afternoons in January, March and November with a demand response event. Effects of dynamic and static electricity pricing on delivery of DR were analysed. In line with previous findings factors like seasonality and pricing were found to influence the flexibility potential of the community. Operational differences found between the centralised and decentralised MPC setups highlight importance of the control setup for scalability and delivery of flexibility.