Wind-Hybrid Systems and Rural Electrification: Experiences from India

Introduction

Energy is vital for the economic growth of any country. For this purpose energy security is crucial and only renewable energy source that are sustainable and free from greenhouse gases like Solar, Wind, small Hydro and Bio is the answer. This calls for a paradigm shift in the use of energy sources so as to ensure that by the time fossil fuel reserves become extinct renewable energy has attained commercial acceptance.

Nearly 70% of India’s population is based in villages where agriculture activity takes place, where plenty of open space is available but the dwellings are wide-spread unlike urban areas where they are concentrated. The power supplied in these areas yet continues to be subsidized clubbed with high T² & D (Theft, Transmission and Distribution losses) which are getting in the way of utilites being financially healthy. In order to improve the financial status of the utilities, Small Wind Energy (SWE) system in combination with Solar Photovoltaics (PV) system as a Hybrid system can help overcome the losses, besides reduce dependence on the import of fossil fuel.

Village electrification in India

As per 1991 census there are 593,732 Villages in India of which 439,502 Villages are Electrified 74%). The amusing definition of village electrification in India is minimum 10% of the households in the village connected to the grid. Households concentrated in a given locality get electrified and isolated households within the village are deprived of power. As per the latest information available for rural India out of the 138,271,559 households only 78,090,874 are electrified (56.5%). It is noteworthy that most of the regions un-electrified are backward areas where source of income is virtually not existence. Thus providing any form of power will not realize its commercial value.

The status of un-electrified households as on December 2005 is as shown in Table 1. Six States with 80% or more households yet to be electrified. States in this category constitute 43% of country’s total rural households. Albeit majority of them do not receive power when it is most needed (post dawn) due to poor quality of power. It is here that SWES - PV Hybrid systems can be useful for overcoming this shortage.

Micro Power Systems – Ideal solution for Energy Independence

For India to aim for “Energy Independence” on priority micro based renewable energy systems like SWES, PV, mini and micro Hydro have to be encouraged on a mass scale that can be used by individual roofs in the villages. The key to this is elimination of subsidies and use of independent renewable energy systems so that T² & D can be virtually wiped-off and the resultant power saved can be diverted to Industries, which is today the back-bone of the country’s economic growth.

Table 1: Status of un-electrified rural households in India

However it is very important that long-term favourable policies are framed that will encourage mass participation. SUBSIDIES AT ALL TIME IS NOT THE ANSWER since masses tend to get accustomed to it, besides it is not practicable to extend subsidies to everybody. Majority of the un-electrified households in the country are in such regions where economic activity is virtually not available or have farming on a very small piece of land, income from which will not be sufficient to pay for the expenses in investing in SWES-PV Hybrid system. The present subsidy offered by Ministry of Non-conventional Energy Sources is as given below in Table 2.

The remaining cost of the system and all other expenditure related to packing & forwarding, transportation, installation and commissioning of the system will be met by the state nodal agency and /or users of the system. In case of community use, in addition to the state agency share, the beneficiaries will also meet a part of the cost of the system through initial deposits and/or monthly payments, to ensure beneficiaries’ stake in the system.

Table 2: Central Financial Assistance from MNES, Govt. of India for Small Wind & PV systems

SWE-PV Hybrid System the ideal solution:

India is predominantly a low wind speed country although the western and southern states have average wind density of 300 Watts/m². The solar radiation falling over India is about 5,000 trillion kWh / year. There are about 300 clear sunny days in a year in most parts of the country. The average insolation incident over India is about 5.5 kWh / sq. meter over a horizontal surface. Thus Solar PV is a very important power source for meeting rural electricity demand.

Fig. 1 shows the map of Wind density and Solar power availability in India. It is however interesting to note that the mapping holds too good for grid based Wind farm development and where infrastructure is available for power evacuation and transportation.

Often authors or speakers during seldom forget to quote India’s Wind energy potential as 45,000 MW. This holds good for Wind farm development but should not be a deterrent for SWE. The advantage with independent SWE is that it can be installed wherever open space is available and at a height of 15 metres so that wind is captured sufficient enough to excite a generator to produce power so as to increase the efficiency. This should be vital for promotion of SWES and with mass production, cost economics can be easily achieved.

Fig. 1a Wind density map of India

Fig 1b: Solar radiation map of India

Use the route "Pay the Beneficiary" rather than "SUBSIDY"

Rural power in India is highly subsidized compared to commercial power and in majority cases theft takes place. Instead of paying direct subsidy for the SWES-PV Hybrid system installed by the beneficiary, the utility should pay the beneficiary for the space taken for the Hybrid system installed and also for the generated power fed to the grid. For the purpose a local low voltage grid system can be commissioned and the resultant power generated be collected and fed to the nearest sub-station. Not all of the rural power requirement can be met by way of SWE-PV Hybrid system but it can be useful as a supplementary source.

The beneficiary must be paid the prevailing commercial rate from the power generated from the hybrid system. This will have a commercial impact on the beneficiary as it will receive a source of income. It will also reduce the burden on government to provide subsidy to all as yet SWE-PV Hybrid system cost is prohibitive to sustain on its own. The target should be those 138 million electrified rural households as per the data given in Table 1 who have the capacity to pay. Once the success can be proved, the nearly 78 million households un-electrified can be gradually targeted as by that time the systems would become affordable enough within the reach of a common villager in India.

Promote Direct use in Niche Commercial Applications

The direct use of SWE-PV Hybrid system must be encouraged for niche applications where power is purchased from the utility at commercial rates. E.g. community water pumping, communication towers, highway lighting, bridges, beacon lightings, light-houses, boats and applications where diesel generator is widely used. For the purpose it is very essential that micro financing policies are made available with the rural banks. An equivalent credit as offered by way of subsidy on conventional power must be extended on every watt of power produced by SWE-PV Hybrid system so that it receives acceptance.

Summary of the Findings of the Field Survey

A typical daily power requirement of an middle income household in rural area was identified as shown in Table 3.

The daily requirement is about 3030 Wh or nearly 3 kWh/day. Te monthly requirement thus works out to 90 kWh / month and annual requirement is nearly 1100 kWh.

During the monsoon season (June - September) the average wind speeds are in the range of 5 - 7 m/s. Referring to Table 4 at an average speed of 6 m/s the monthly average production can be considered as 140 kWh, which is sufficient to meet the daily requirement. Even if sunlight is not available PV system need not be active though there will be some generation as a result of diffuse radiation. During other months the average wind speed can be considered at 4 m/s and again from Table 4 the monthly production will be 48 kWh or 1.6 kWh / day. The deficit of (3.03 - 1.6) 1.43 kWh can be met by PV system.

On a normal sunny day 1kW of PV produces 5.5 kWh, so the PV component of the Hybrid system will be (1.4 / 5.5) 255 Watts-peak capacity or say 250 Wp to the nearest capacity.

So the ideal SWE - PV Hybrid system will be of 900 W capacity comprising of Small Wind generator of 650 Watts and Solar PV module of 250 Wp.

Adding 10% for various losses in order to be connected to the grid, the final capacity will be 1000 W or 1 kW. India being a tropical country hence Solar energy can be predicted hence the capacity addition should be considered in Solar PV as a factor of safety.

Thus the desired SWE-PV Hybrid system of 1 kW comprising of Small Wind generator of 650 Watts and Solar PV module of 350 Wp can meet the basic electricity needs of a typical rural household.

For every 1,000 kWh of power to be generated 0.33 tonnes of coal is burnt. Even if 25% of the electrified rural households are targeted (approximately 35 million) assuming this figure lives in a moderate to high wind regions, then the annual coal savings will be:

Annual Coal Savings for 35 million SWES-PV Hybrid System
= (1100 / 1000) x 0.33 x 35,000,000
= 12,705,000 tons

Table4: Monthly energy ESTIMATE (kwh) of SWES of various ratings (courtesy UNITRON Energy)

Village survey findings

A sample survey on acceptance of SWES-PV Hybrid system amongst 1000 households in 6 villages was carried out in Maharashtra state located in western part of India. The villages were a mix of profiles: one having proximity to industrial belt, one with irrigated agricultural fields, one close to urban city, etc. The systems were divided into 3 Types:

• Type 1 - SWES-PV Hybrid costing appx. Rs. 75,000 and virtually meeting the daily electricity needs
• Type 2 - SWES costing around Rs. 50,000 but meeting 50% of the daily electricity needs
• Type 3 -PV system costing around Rs. 100,000 meeting the daily electricity needs

Households use kerosene for lighting and cooking at 65:35 ratio. On an average they require 3-4 hours of lighting daily. The loss of lighting hours from electricity daily varies from 2 hours to as high as 7 hours. Due to this kerosene finds distinction as the reliable fuel source for lighting. Due to non-availability of electricity/ kerosene in households the loss recorded is domestic work, studying and cooking. Besides many reveled that this was also making them consider migrate to urban places. Also kerosene costs as high as Rs. 25/- per litre (Rs. = Indian Rupees INR; Exchange Rate September 2006: 1 US-$ = Rs. 46.50) and only midget quantities are available in rations shops. The usage of candle is maximum about Rs. 25/- per month. 1% of them have generators while battery or UPS systems was only 0.5%. Lighting, Fan and T.V is observed in 80% of them.

In the commercial sectors like hotels, hospitals, shops and telephone booths, PV has found positive response with 90% of respondents, since loss of light during peak hours in evening means loss of business. About 10% of the shops, hospitals and hotels have generator, and most of them have necessarily a battery, since during power failure their electronic measuring instrument fails to work thus resulting in loss of business. Their average trading per hour is about Rs. 25/-.

Finally all the respondents in all the clusters have shown more prominence to a Type1 system. Commercial establishments have given utmost favour for Type1 hence they should be the best target to approach and start with. This proves that the business potential definitely exists subject to the condition that the 1 kW system is made available to end user nett at Rs. 75,000/- in easy installments. The acceptance by type of system in different cluster is as given in Fig 2.

Fig. 2 : Graph of Acceptance by type of System

Conclusion

It can be concluded that SWES-PV Hybrid system can definitely help mitigate the energy crisis that will arise as a result of dwindling fossil fuel reserves. India's energy dependence from energy imports can be thus reduced. The country has high potential of Solar energy and majority areas with Wind energy. The combination of these sources as a Hybrid system can hugely benefit to meet the rural electricity demands. It can also help in employment generation as several manufacturers and service personnel will be required for the purpose.

Links and References

• http://mnes.nic.in
• http://powermin.nic.in
• http://www.cwet.tn.nic.in
• http://recindia.nic.in
• http://www.iredaltd.com

Jaideep N. Malaviya
Malaviya Energy Consultancy
Pune, India
http://www.malaviya.in