Water supply in rural islands or coastal areas is a basic task for people's livelihood. The all-pervading reverse osmosis (RO) technology is an energy-intensive process. To achieve sustainability goals, the development of renewable driven power supply system for RO plant is significant. Nowadays, the energy, economic and environmental indicators have rarely simultaneously investigated for the type of renewable power supply system with underwater compressed air energy storage (UW-CAES) for RO plant. In this paper, an energy-economic-environmental trade-off multi-objective optimization for such system is proposed in both grid-connected and off-grid schemes. A bi-level optimization strategy based on MOPSO algorithm and TOPSIS method is adopted to seek the optimal configuration and energy management strategy. A real-world case is implemented to demonstrate this method. The results show that the TPC/COE/EC set in optimal grid-connected scheme system is 3.716 × 10⁶¥/0.814¥kWh⁻¹/795.922 kg with a configuration of 511 PVs, 12 WTs and a 900 m³ bag volume in UW-CAES. Whereas, the TPC/COE/EC in optimal off-grid system is 4.076 × 10⁶¥/2.305 kWh⁻¹/566.254 kg with a 705/8/900 m³ configuration. In energy perspective, both schemes can match the load well. In economic perspective, the grid-connected scheme has a considerable profit, whereas the off-grid has no revenue. In environmental perspective, both schemes can reduce the carbon emission remarkably.

农村海岛或沿海地区供水是民生的基本任务。无孔不入的反渗透 (RO) 技术是一个能源密集型过程。为实现可持续发展目标，开发可再生能源驱动的反渗透设备供电系统意义重大。目前，对于RO装置水下压缩空气储能（UW-CAES）的可再生能源供电系统类型，能源、经济和环境指标很少同时进行研究。在本文中，在并网和离网方案中都提出了针对此类系统的能源-经济-环境权衡多目标优化。采用基于MOPSO算法和TOPSIS方法的双层优化策略寻求最优配置和能量管理策略。实现了一个真实案例来演示此方法。结果表明，最优并网方案系统的TPC/COE/EC集为3.716×10⁶ ¥/0.814¥kWh ⁻¹ /795.922 kg，在 UW-CAES 中配置 511 个 PV、12 个 WT 和 900 m ³袋体积。而最佳离网系统中的 TPC/COE/EC 为 4.076 × 10 ⁶ ¥/ 2.305 kWh ^-1 /566.254 kg，采用 705/8/900 m ³配置。从能源的角度来看，两种方案都可以很好地匹配负载。从经济角度看，并网方案有可观的利润，而离网方案没有收益。在环境方面，这两种方案都可以显着减少碳排放。