Solar-DC deployment experience in off-grid and near off-grid homes: Economics, technology and policy analysis

Abstract

India is a power deficit country and one third of its homes are off grid or near off grid. This paper presents an efficient and affordable Solar DC solution for powering such homes. Though several solutions have emerged in the past for powering these homes, those have been expensive and energy inefficient. These solutions rely on several DC to AC and AC to DC conversions, to feed the widely used AC home loads, thus, wasting a large chunk of the expensive power. The proposed Solar DC solution for off-grid homes (OGH) is developed to use the generated PV power efficiently. With this solution, the panel and battery size is reduced by 2 to 2.5 times and the cost to power a house is reduced to nearly half the cost of the existing solutions. The paper also presents a techno-economic comparison between the proposed OGH solution with some existing solar systems.

Evaluation of the reliability of solar micro-grids in emerging markets – Issues and solutions

“…protection schemes) [75] which complicates a direct comparison of different networks without more information on their characteristic. However, DC has a second simplicity benefit which is the reduced number of power conversion phases required in PV-supplied systems resulting in significant energy efficiency gains [76] [77]. Energy efficiency makes DC distributed PV power grids more energy frugal by architecture.…”

DC Grid for Domestic Electrification

“…An effective Maximum Power Point Tracking (MPPT) algorithm to obtain constant DC voltage of 12 V or 24 V using a PI controller is studied in [6]. An Off Grid Home (OGH) which is inverter less system to power lighting loads are deployed in [8].…”

“…In rural areas, usually the application side dispersal transformer having a 20% to 25% reduced voltage than the general fixed values. Operation of conventional induction motor based devices like household fans with such voltage variation from the general fixed values may results in higher iron losses, which may leads to the permanent damage of motor [8]. The calculated values of various converter parameters for energizing <24 V devices are tabulated in Table 2.…”

“…To encourage solar rooftops the Tamilnadu government provides huge incentives and almost 30% subsidies to buildings incorporating solar rooftops. This movement has encouraged the studies and improvement on Low Voltage DC arrangements, as they are suitable for residence applications as well as can be easily integrated with renewable energy sources and storage systems [8,9]. The rising demand for aggregating renewable energy resources is bringing back DC into the energy distribution frame since it is easy to integrate renewable sources into the grid in such case.…”

An overview of low voltage DC distribution systems for residential applications

“…The studied showed that the DC system is more efficient and also brings cost savings for the users, by reducing the electricity bills, and the cost of the system. In [20], the conceptual implementation of low power solar system is shown. The system is designed to cover the minimum needs of a low-income household in India.…”