Abstract
Salinity gradient power (SGP), also known as blue energy, represents a promising renewable energy (RE) source that can diversify global RE portfolios and address energy security challenges. The Philippines, with its extensive network of estuaries where river outflows meet the sea, offers a strategic opportunity for deploying SGP technologies like the pressure retarded osmosis (PRO). PRO utilizes the osmotic energy produced when freshwater diffuses through a semi permeable membrane into seawater, generating pressurized flow that can drive turbines for electricity generation. This paper explores the energetic and economic feasibility of stand-alone PRO-based power generation in the Philippines, highlighting its potential to support the country’s transition to RE. The work employed a process simulation that integrates unit operation models with mass and energy streams. Key economic indicators were evaluated, including net present value (NPV) for total project feasibility, internal rate of return (IRR) for the annualized return rate, and discounted payback period (DPP) for the time needed to recover investments. The levelized cost of PRO energy (LCOE), reflecting the lifetime cost per kWh produced, was compared against benchmarks from other RE sources. Results indicate the viability of PRO, demonstrating a positive NPV at a 10% discount rate, with a 7-year DPP and an IRR of 12.16%. The study found that the LCOE value of $0.17 per kWh, using cellulose triacetate membranes with approximately 90% efficiency, is cost-competitive with other RE sources. However, advancements in membrane properties, particularly durability and water permeability, are essential to improving both cost-effectiveness and scalability of PRO power plants. This investigation emphasizes the potential of blue energy as a RE source uniquely suited to archipelagic countries like the Philippines. By prioritizing innovation in membrane technology, PRO can transition from an emerging technology to a cornerstone of sustainable energy strategies, aligning with global carbonization efforts.