Under-estimated small Off-grid Roof top solar PV systems to be re-examined

The utility scale solar PV projects have grown up significantly in India over the last 5 years. Focus is shifting on roof top (RT) solar PV systems, as is evident in the Jawaharlal Nehru National Solar Mission (JNNSM). Under the mission 40,000 MW of RT solar PV systems are to be installed by 2022.  In the light of falling prices of solar PV modules, both off-grid as well as grid connected roof top solar PV systems seem to be a viable and workable solution in addressing nation’s energy and environmental issues.

Potential of Roof Top Solar PV systems:

As per the 2011 census, over 140 million houses in India has proper roof top spaces that can accommodate up-to 3 kW of solar PV system. I am talking of residential houses not about the commercial buildings, shopping malls, educational institutions etc. RT solar PV systems can be vital in rural areas. Even a 300 W roof top Solar PV system on each of these 140 million houses will tremendously add to the Renewable Energy portfolio. 

Issues with Grid connected Solar PV systems, which are yet to be streamlined:

Looking into the extent of execution of solar PV systems in India, the weightage seems to be primarily on the grid connected RT solar PV systems, particularly on the government establishments and buildings. The rising electricity tariff has already given RT solar PV the much required niche and made it viable even without the support of any subsidy. 

Lack of clarity  on rules and regulations, technical and safety issues, power quality, metering and bill related issues pose tiresome proposition to both utility and owners of grid connected RT solar PV system. This is true particularly in the state of Madhya Pradesh, where the net metering has just started. Even the Discom officials are unaware of the procedures. Apart from that a grid connected RT solar PV system needs the approval of two government bodies i.e. the Urja Vikas Nigam and the related Distribution Company to get it installed; which as we know a time consuming and tiring exercise.

Potentials of Small scale Off-grid solar PV system needs to be Re-evaluated:

Small scale off-grid solar PV system is seen as underdog. In my opinion, such PV system has a huge potential in this country, provided the awareness is created. A properly worked out small RT off-grid solar PV system on affordable initial capital may lead to better utilization of unused roof top space. These RT solar PV systems can be seen as a sustainable remedy to frequent power cuts and peak power shortage. It’s better to promote small off-grid solar PV systems of say 200-300 W on every possible roof top. It hardly needs 25 square feet of space and can be arranged in a variety of fashion (refer fig1).

Fig.1: Small scale Off-grid Roof top Solar PV system of 300 W

Such small off-grid solar PV systems are capable of energizing the essential light and fans, TV and computer requirement of a three room house. The initial cost is also affordable, say around 40,000 INR with battery back-up, even less than 25,000 INR when an existing battery-inverter set is converted into a solar PV-battery-inverter system. There is no need to go for cheap popular gimmick as subsidy etc, provided the common mass is made aware. Such small solar PV systems are easy to install, and budget friendly.

Even a 20-25% of the residential energy requirements is fulfilled by these small but effective RT solar PV systems, it may be seen as a boon. A solar PV system is more worthy if the self-consumption is about 50% or more. The same energy can be routed to industries or commercial establishments and that too at a better tariff.