Hybrid energy systems for remote island electrification in the Philippines

Abstract

Climate mitigation measures are integrated in various governmental and commercial initiatives. The sector of electrification and energy is no exception to this. For remote island communities however, the access to reliable and affordable electricity comes with additional difficulties. The effects of climate change, energy dependency and isolation are more pressing here. Island electrification therefore requires more customized or flexible solutions compared to urban environments. Using local renewable resources can significantly improve the electrification status and independence while aiding sustainability goals. The various renewable resources contain different potentials due to availability and location and any combination of multiple resources can be accompanied with uncertainty of effectiveness and complexity of integration. Seeing that island communities have direct access to ocean energy with its global potential of 16 TW, the potential for tidal energy, and in particular tidal stream energy, is assessed in combination with the more mature technology of solar PV as to reduce the reliance on conventional energy systems and investigate the possibility of fully renewable hybrid energy systems for small scale island applications. In order to assess the technical and financial aspects of such a system, first the context of implementation needs to be clarified. Identifying the technical generation principles, resources and characteristics of each component to be integrated. To do so a framework was designed for fully renewable energy system feasibility assessment. As an assessment strategy it was decided to prioritize reliability and subsequently assess the related costs and competitiveness compared to conventional hybrid (diesel-fueled) energy systems. This was followed with a selection of performance indicators and software optimization tools to simulate the full system behavior over the desired lifetime of 20 years. Subsequently, an expedition was held to a targeted location for the case study in this research, selected by WEnergy global Pte Ltd, to create the necessary knowledge base for future reference and investigate local tidal potential. The energy demand was quantified, and data was collected on both the local tidal energy potential and tidal system to further calculate representative tidal stream generation profiles. By using a simple tidal energy model, the representative hourly current velocity datasets could be created necessary for the simulations. An inhouse Excel based simulation model was adapted to account for tidal energy implementation, and a specialized hybrid energy system optimization software was used to validate and improve the optimization speed, accuracy and sample size. Using the available data and models the technical performance in relation to the installed generation capacity, battery storage capacity, and complementarity of resources could be analysed. The selected key performance indicators were calculated for multiple configurations and compared to a conventional hybrid energy system for its commercial feasibility. For the specific case in this study insufficient tidal energy could be generated. However similar tidal type systems were found to contain sufficient potential in combination with a suitable turbine providing up to 200 [MWh] turbine per year. Resulting from the optimization the implementation of tidal stream energy in combination with solar PV and a battery storage system showed to be technically challenging but capable of providing in the annual island community energy need of 2.5 [GWh]. Commercially however, it remains uncompetitive even in a best-case scenario with a levelized costs of energy of 0.45 [$/kWh] compared to a cost of energy of a conventional system of 0.37 [$/kWh]. This study hopes to aid in the acceleration of sustainable electrification and climate change mitigation, the further pursuit of tidal energy implementation as a local renewable energy sources to reduce energy dependency and to provide more opportunity for improvement of socio-economic conditions in remote communities in The Philippines in line with the objectives of WEnergy Global Pte Ltd.