JOIN USHumanity now has the means to minimise its dependence on emission causing fossil fuel-fired power generation and switch over to clean energy. Even individuals can set up solar rooftop photovoltaic systems (SRPS) to meet their energy needs.
Photovoltaic (PV) effect is the method of converting sunlight into direct current (DC) electricity. Some semiconductor materials produce electric current when light falls on them.
A PV system comprises of solar panels that are composed of modules, and cells made of special semiconductor materials, placed behind a special glass.
Solar panels can be installed on the rooftops of homes/offices/factories that are presently not put to commercial use. Since most electrical applications use alternate current (AC), an inverter is typically used to convert DC into AC. The system can be either grid-connected or a standalone application.
PV technology has been in existence for almost five decades. Because of their until-now-prohibitive costs, they were initially used only in special applications such as powering of satellites. Now the costs have come down drastically, thanks mainly due to incentives provided by national governments. In addition, the exponential expansion of worldwide solar PV capacity has cut costs drastically.
Several nation states have even initiated measures to reduce support subsidies as they are no longer required. Even in India, the Ministry for New and Renewable Energy (MNRE) recently indicated that it is to be reduced up to 15 per cent from the present level of 30 per cent. Net metering, however, is an essential framework for SRPS to remain relevant.
How net metering works
In net metering, solar energy produced by solar panels is converted to AC by a solar grid inverter. The output is connected to the distribution switchboard of the building. The electrical energy flows to the loads of the buildings (lights, refrigerators, fans, etc.). If the solar power produced is more than what the building loads consume, then it will automatically flow to the distribution company’s network (the grid). If the power generated is less than what the building requires, than the shortfall will be drawn from the grid.
The meters used for net metering measure both power from the grid to the consumer, and power from the consumer to the grid. According to recent reports, almost 17 Indian states have issued policies for net metering and Karnataka is among them. BESCOM, for instance, pays Rs 9.56 for every unit of excess power fed into the grid by an SRPS if it doesn’t avail subsidy. Also, Karnataka allows SRPS to generate up to 1 mW.
The guidelines issued by MNRE on June 26, 2014, for the implementation of the ‘Grid Connected Rooftop and Small Solar Power Plants Programme’ explicitly states that the country “has a huge potential for deployment of grid-connected rooftop solar photovoltaic power generation plants”.
India depends on imported crude, gas, and coal to meet its energy needs. The country is blessed with abundant sunshine for almost 300 days in a year and solar power plants, once installed, can generate power for many years economically and without polluting the environment.
Solar power is competitive
Creating awareness among people that it pays to use solar power will encourage them to go for it. MNRE’s guidelines say that in most cases the cost of generating solar power at present is a little higher than the tariff charged from consumers by Distribution Companies (DISCOMS)/Distribution Licensees (DL). It goes on to say that with capital subsidy, it may be possible to generate power between Rs 5 to Rs 6.50 per unit for the next 20 years, which is cheaper than diesel generator-based electricity, and this could also be cheaper than the cost at which most DISCOMS/DL make power available to the same consumer.
With all the key drivers for the widespread use of solar PV systems in place, what is required is awareness and appropriate business models. In India, while corporates, organisations, factories, etc. are making advances, it is different for individual home owners. India is a developing country and capital is expensive. For the vast majority of common people, affordability is paramount.
For many, keeping upfront capital costs low is more important than monthly recurring expenses. Policy makers will have to take these nuances into account while deciding on appropriate ways to persuade even individual homeowners to adopt rooftop solar generation. Encouraging third-party developers to own the solar rooftop systems and enter into a lease/commercial arrangement with the rooftop owner may be a more attractive proposition.
Regarding capital costs, Prakash Nayak, Chairman, IET (The Institution of Engineering and Technology) Power Panel, said that it costs close to Rs 150,000 per kWp with a 10-hour battery backup. Elaborating further, he indicated that a 1 kWp system will generate around 1,500 units of electric power in a year, equivalent to around Rs 9,000. From the perspective of investment, he said that “it is not a very attractive proposition for individuals, except for the feel-good factor that power is available most of the time even during grid breakdown.”
He felt that to make the scheme more attractive, the payback period must be brought down to 4-5 years. There is greater awareness now about the benefits of rooftop solar photovoltaic systems among all stakeholders and the trend will gain momentum in the years to come if net metering schemes are fine-tuned suitably.
(The author is an independent industry analyst/columnist and automation consultant)