With the cost of rooftop solar photovoltaics as well as home storage rapidly dropping, local generation is becoming increasingly attractive to homeowners, businesses and communities who want to reduce their energy costs and/or to improve the reliability of their supply.
The potential for rooftop PV is massive. In the US, for example, over 8GW of rooftop panels have been installed since 2000. Google’s plan to harness its Earth mapping to enable individuals to determine their own rooftop’s potential focused (initially at least) on the US, is likely to increase significantly. [Engerati-Google’s ‘Project Sunroof’ To Map Solar Potential]
China, the largest manufacturer of solar PV, is a fast growing market and during the last year approximately 2GW of rooftop PV was installed.
Rooftop PV in India
India’s Prime Minister Narendra Modi’s vision is to add 100GW of solar energy to the nation’s grid in the next 7 years. In addition, the Ministry of New & Renewable Energy (MNRE) has set a target of 40GW for rooftop solar by 2022, starting with 200MW in 2015-16. This will rapidly ramp up to 4.8GW in 2016-17, 5GW in 2017-18, 6GW in 2018-19, 7GW in 2019-20, 8GW in 2020-21 and 9GW in 2021-22.
According to a study by the Energy and Resources Institute (TERI), the estimated total rooftop PV potential is 124GW. India's total solar potential is estimated at 750GW.
Based on state power consumptions and consequent solar power requirements to meet the corresponding Renewable Purchase Obligations, targets have also been set for the individual states. Of these, 15 states have a target of 1GW or greater, including Maharashtra with 4.7GW, Uttar Pradesh with 4.3GW, Tamil Nadu with 3.5GW and Gujarat with 3.2GW.
Incentivizing rooftop PV in India
Typical installations are anticipated from 1kW up to 500kW and subsidies up to 15% of the cost will be available for all building types, except private and commercial and industrial, which instead will benefit from accelerated depreciation benefits.
Other benefits include tax holidays, customs and excise duty exemptions and the opportunity to include rooftop PV as part of a home loan or home improvement loan.
So far 20 states have orders to promote rooftop solar systems, including net metering. At least one, Haryana, has gone a step further requiring all buildings on a plot size of 420m2 and above to install solar PV with a capacity of 1kW or 5% of the connected load, whichever is greater.
Manufacturers will also benefit through a domestic content requirement for all installations that receive a government subsidy.
Solar PV in India
Solar PV has been steadily gathering momentum in India. For example under the Jawaharlal Nehru National Solar Mission (JNNSM) since 2010, 3.4GW of grid solar PV has been commissioned, along with the sanctioning of 357MW of off-grid solar applications.
It is proposed to set up at least 25 solar parks and ultra mega solar power projects of at least 500MW targeting over 20GW of installed capacity by 2020.
At a rooftop level, the country also holds the distinction of having the largest rooftop PV installation on a single roof – a 7.52MW installation comprised of more than 30,000 panels on a 94,000m2 asbestos sheet roof at Amritsar in Punjab. The project, which was commissioned in June 2014, was by L&T Construction, India's largest solar EPC company.
Another significant single rooftop installation in India is a 1.05MW facility by Sterling and Wilson, another leading solar EPC company, on a denim and industrial manufacturing plant of KG Fabriks Ltd in Perundurai town in Tamil Nadu state.
These new plans, while setting in motion a rooftop revolution in India, will present new engineering and business challenges, but ones that will undoubtedly be overcome.