Energy-efficient off-grid systems—review

Abstract

Globally, around 1.1 billion people do not have access to electricity and 84% of the population who do not have modern energy access are living in rural and remote areas of developing countries. Since the loads are far from the grid and providing the connection by extending from the main grid requires a high investment associated with long and costly transmission and distribution lines, addressing the problem requires innovative solutions. Therefore, off-grid microgrid systems, using solar photovoltaic and storage systems, integrated with very high-efficiency lighting appliances, are a promising solution to supply energy for rural and remote location in areas which lack access to the electric grid. This paper presents an overview on the existing solar photovoltaic technologies for off-grid systems including the most recent plug and play solutions. A characterization of the most common strategies used for control, communication and metering of microgrids is presented, as well as the recent evolution of the associated component technologies. The security and protection systems used to protect the system against theft or robbery of the systems itself or energy theft in remote areas are also addressed. Additionally, a resumed characterization of the sociologic profile and motivation of people to damage off-grid systems is presented. An overview on the main off-grid appliance market evolution and efficiency trends, in terms of energy efficiency, is also addressed in this paper. Finally, a set of recommendations to promote cost-effective systems is made, considering the market evolution path and the large growth potential of off-grid systems. There is an urgent need to reduce the total system costs, namely the soft costs of new microgrid systems in order to further accelerate the market growth, as well as widely accepted open standards to regulate and develop the market.