What is renewable energy?

Energy derived from natural processes (e.g. sunlight and wind) that are replenished at a faster rate than they are consumed. Solar, wind, geothermal, hydro, and some forms of biomass are common sources of renewable energy.


How much of the world's energy comes from renewable sources?

In 2009, the world relied on renewable sources for around 13.1% of its primary energy supply, according to IEA statistics. Renewables accounted for 19.5% of global electricity generation and 3% of global energy consumption for road transport in the same year.


How much has wind power grown since 2000?

Global wind power capacity was 238 Gigawatts (GW) at the end of 2011, up from just 18 GW at the end of 2000, with an average growth rate of over 25% over the past five years. 


How much has solar photovoltaic (PV) grown over the last decade?

Solar photovoltaic (PV) directly converts solar energy into electricity using a PV cell; this is a semiconductor device. The global total of solar PV was roughly 67 GW at the end of 2011, to be compared with just 1.5 GW in 2000. Over the past five years, solar PV has averaged an annual growth rate of over 50%. Growth has been mostly concentrated in a few countries, where PV generates today a few percent of total yearly electricity production.


How much has biofuel production grown over the last decade?

Global biofuel production grew from 16 billion litres in 2000, to more than 100 billion litres in 2010. This biofuel provides around 3% of the world’s fuel for transport. (In Brazil, biofuel provides 23% of all transport fuel, compared with 4% in the United States and 3% in the European Union).


What are variable renewables?

Variable renewables include wind, solar, wave and tidal energy, and are based on sources that fluctuate during the course of any given day or season. Variability is not new to power systems, which must constantly balance the supply and variable demand for electricity, and face all kind of contingencies. However, large shares of variable renewables supply may increase pressure on power systems, which may need increased flexibility to respond to this balancing issue. More flexible generating capacities (e.g. gas and hydro power plants), interconnections, storage (e.g. with pumped-hydro plants), and/or load-management empowered by smart grids, can be combined to provide the required flexibility.


What is the impact of renewables on energy security?

Energy security and diversification of the energy mix is a major policy driver for renewables. Growth of renewables generally contributes to energy diversification, in terms of the technology portfolio and also in terms of geographical sources. Use of renewables can also reduce fuel imports and insulate the economy to some extent from fossil fuel price rises and swings. This certainly increases energy security. However, concentrated growth of variable renewables can make it harder to balance power systems, which must be duly addressed.


Should renewables be subsidised?

The IEA believes that further growth of renewable energy is essential for a secure and sustainable energy system. Transitional economic incentives that decrease over time are justified. Incentives are sometimes needed to stimulate cost reductions through technology learning, such as improvements in manufacturing, increased technology performances, economies of scale and larger deployment. Incentives may also be justified to secure  additional energy security and environmental benefits. Current policies have started to deliver in this respect. Nevertheless, in several countries, the design of support policies has not been ideal, and this has led to higher than anticipated levels of deployment and excessive policy costs. The IEA offers policy makers guidance on how to steer policies on renewables.


What is a “Feed-in Tariff” (FIT)?

A Feed-in Tariff (FIT) is a policy mechanism (an instrument of law) designed to encourage the adoption of renewable energy sources and to help accelerate the move toward grid parity (when renewable energy sources will have the same costs as traditional sources of electricity such as natural gas, coal, or nuclear).

FITs typically includes three key provisions:

Ø  guaranteed grid access;

Ø  long-term contracts for the electricity produced;

Ø  purchase prices that are methodologically based on the cost of renewable energy generation and tend towards grid parity.


Aren’t FITs just another form of subsidy?

No. FITs do not subsidize the purchase or installation of the equipment used to produce renewably generated electricity, nor do FIT payments come from taxpayers. Subsidies are creative payment schemes used to offset or reduce the true of electricity, and are typically funded by tax payers rather than by electricity consumers

(eg: certain corporate tax credits/exemptions and research tax credits for natural gas fracking), much like the way we pay for construction of coal/nuclear/gas plants, or the disposal of nuclear waste, separately from buying the electricity. Feed-in-Tariffs are an all-in nothing-hidden price for electricity as it is delivered: it’s called a “tariff” because it doesn’t get paid until the electricity is used. Other forms of electricity are heavily subsidized by many different collaborative funding mechanisms (some estimates top $3.5 Trillion/yr globally). Renewable energy that is purchased through a FIT contract has a fully disclosed price that is paid only on delivery: if no electricity is delivered, then they don’t get paid, and regardless, they get no subsidies.


In case of installation of Solar PV Lighting System what will be the available subsidy?

As per the new guidelines of the MNRE, Govt. of India under National Solar Mission subsidy pattern is as following:

1.   Benchmark cost of 1 KW SPV Power Plant is ` 3.0 lacs. The bench mark cost for 37 Wp Solar Photovoltaic Street Lighting System is ` 11,100/- . Out of this, Govt. of India will provide the subsidy of 30% of system cost.

2.   For domestic (home) lighting systems [from 10W to 200W] Refinance Scheme of MNRE-NABARD has been introduced where both capital & interest subsidy are there. The Govt. of India will provide the subsidy of 30% of system cost. 20% of system cost is to be borne by the user as down payment. 50% of system cost will be available from the bank finance with low interest loan through NABARD The National Bank on Agriculture & Rural Development (NABARD). So for further course of action in this respect, interested people may contact to the regional office of the National Bank on Agriculture & Rural Development (NABARD) in Kolkata (Building: Abhilasha-1, 6 Royd Street, Kolkata – 700016) or its District level offices.

3.  For institutional systems [201 W to 500 KW] only capital subsidy will be available.(Low interest bank loan will not be available.) Capital subsidy is ` 90 per Wp or 30% of the system cost whichever is less for systems having battery. This is for Non-profit organizations. For profit making organizations, subsidy amount will be 70 per Wp. For systems without battery; subsidy will be available in the tune of ` 70 per Wp or 30% of the project cost whichever is less. Any type Solar PV applications like replacement of DG set, Solar Powered Sign Board, Solar Powered Mobile Towers, Solar Powered Pump set, Solar Powered Water Purifier etc. are under the provision of the National Solar Mission and the mentioned subsidy pattern will be applicable for that.

Solar PV HLS is a DC System and separate wiring may be required (cost of the same is included in the estimate, indicated above) for it. However existing wiring of electrified households may also be used by using DC to AC converter. Warranty for module is 10 years & warranty for battery is 5 years. Home Lighting System can be designed to meet up the any load demand of the user to operate light, fan points, TV, computer etc. Generally, two days backup is provided with the home lighting systems—so that systems can be operated at least for two days in case of continuous adverse weather conditions. System reliability may be increased further by providing higher battery backup. Then system may function for three/four days, even in adverse weather conditions.

To design the capacity of Solar PV Lighting Systems, following information are required.

Sl. No

 Type of Load

Quantity in nos. 

Capacity (Watt) 

Hours of operation 

For example:





Tube Light









People having conventional electricity at their premises, may avail solar powered inverter, which is nothing but an inverter charged by Solar PV Module. Solar Water Pumping System may also be installed with PV array of 1800 Wp for 2 HP motor capacities. Tentative cost is Rs. 2, 90,000/-. Subsidy will be available in the pattern as detailed above. Solar Powered vaccine refrigerator, solar powered water purifier; solar powered air-conditioning systems are also available in the market. The subsidy pattern may change time to time as per prevailing scheme of the Govt. of India and Govt. of West Bengal.


How to reduce electricity bills in domestic Sector?

To reduce electricity consumption, energy efficiency measures are to be obtained. For example, energy efficient lighting systems are to be installed as per the requirement (type of activity) of the particular room or area. C FL shall be installed at corridors and toilets (instead of incandescent lamp). For areas where lighting systems will be in operation at night for a long time; CFL or LED lamp should be installed there. All existing tube lights having 40 W capacity should be replaced by energy efficient T 5 or T 12 slim tube lights. Solar Water Heating System can be installed in the place of Electrical Geyser to avail hot water with 50-850 C temperature all through the year. The above replacements will correspond to reduction of consumption of electricity without compromising the existing activity level. It is to note that energy efficiency is the cost effective and viable measure to reduce the electricity bill.


Will solar electricity reduce the Electricity bills?

The reply of this question is clearly No. If Solar system will be installed, it is observed that within the life span of the systems, its cost cannot be recovered from the savings of electricity due to the solar system. But solar system can be availed as a reliable option of power supply which is free from external incidents like failure of thermal power plant, failure of local grid etc. It is also a clean and pollution free source of electricity.


How to avail subsidy?

To avail subsidy, the individual (for systems up to 200Wp capacity) may contact to NABARD. Institutions have to apply to WBREDA mentioning the specific requirement in terms of wattage and hours of operation as per format in this respect which is available in WBREDA & MNRE websites. Systems can be installed only after obtaining subsidy sanction order. No subsidy will be available in case where systems have already been installed before obtaining the sanction of subsidy. The subsidy pattern may change time to time as per prevailing scheme of the Govt. of India and Govt. of West Bengal.


What is subsidy for Solar Water Heating Systems & what is the procedure to avail capital subsidy for Solar Water Heating System (SWHS)?

The subsidy pattern for Solar Water Heating System is as following:

Sl. No

Type of Collector

Capital subsidy amount per sq. meter of collector area [`/sq. m]


Evacuated Tube Collectors (ETCS)



Flat Plate Collectors (FPC) with liquid as working fluid



Flat Plate Collector with air as the working fluid














From a 1 sq. meter SWHS, 50 liters hot water is available per day. From this system, hot water is available almost for 365 days in a year with average temperature in the tune of 400 to 950 C. The life of the system is 20 years. The way to avail subsidy for the SWHS is same as Solar PV Street Lighting System. First, the user has to place application. Then WBREDA will sanction the application and will issue subsidy sanction letter for eligible application (or will communicate the reason for its not sanction). After receipt of sanction; the applicant will have to place their user contribution portion to WBREDA. After receipt of fund, WBREDA will install the system within 60 days from the date receipt of fund. The subsidy pattern may change time to time as per prevailing scheme of the Govt. of India .


For what areas of Renewable Energy, capital subsidy is available?

In addition to above mentioned cases, Capital Subsidy is available for following Renewable Energy Programmes also:

a. Bio Energy (Biogas & Biomass)
b. Battery Operated Vehicle [two & four wheeler]
c. Remote Village Electrification (RVE) Programme