Computer Model for Financial, Environmental and Risk Analysis of a Wind–Diesel Hybrid System with Compressed Air Energy Storage

Abstract

Remote and isolated communities in Canada experience gaps in access to stable energy sources and must rely on diesel generators for heat and electricity. However, the cost and environmental impact resulting from the use of fossil fuels, especially in local energy production, heating, industrial processes and transportation are compelling reasons to support the development and deployment of renewable energy hybrid systems. This paper presents a computer model for economic analysis and risk assessment of a wind-diesel hybrid system with compressed air energy storage. The proposed model is developed from the point of view of the project investor and it includes technical, financial, risk and environmental analysis. Robustness is evaluated through sensitivity analysis. The model has been validated by comparing the results of a wind-diesel case study against those obtained using HOMER (National Renewable Energy Laboratory, Golden, CO, United States) and RETScreen (Natural Resources Canada, Government of Canada, Canada) software. The impact on economic performance of adding energy storage system in a wind-diesel hybrid system has been discussed. The obtained results demonstrate the feasibility of such hybrid system as a suitable power generator in terms of high net present value and internal rate of return, low cost of energy, as well as low risk assessment. In addition, the environmental impact is positive since less fuel is used.Energies 2019, 12, 4054 2 of 23 making well suited for the deployment of hybrid systems. Wind-diesel hybrid system with compressed air energy storage (WDCAS) appears as a cost-effective alternative to supply electricity and to ensure diesel generator operational efficiency. The combination of these sources with an energy storage system (ESS) helps to balance variations in power supply and demand.A wind-diesel hybrid system is a stand-alone power system with wind and diesel generators. These systems are recommended for medium scale applications when the use of diesel generators is unavoidable. ESS integration facilitates a hybrid stand-alone system to optimize energy usage while maintaining efficient demand response. Compressed air energy storage (CAES) appears as an economically mature technology. Cost, simplicity, lifespan, fuel consumption and greenhouse gas (GHG) emissions are all influential factors that determine the competitiveness of this technology for wind-diesel hybridization. Moreover, CAES represents a promising solution to store electricity derived from kinetic energy of air at a particular time for further utilization.WDCAS operates according to compression-decompression cycles. The overall performance is subject to load power requirements, energy sources availability and energy storage level. The principle consists of two main phases. During high wind speed conditions, the excess of air is compressed and stored in a reservoir, when the energy is needed, the stored compressed air is released to drive a turbo-generator for electricity production. During low wind speed conditions,...