TABLE OF CONTENTS Chapter No. TitlePage.No.

Bonafide

Abstract

introduction

ABSTRACTThe main point of concern today is to minimize the usage of conventional sources as they are depleting at a faster rate and we are at the verge of totally losing the fossil fuels if we consume them at present rate. So we should conserve the fossil fuels. but how to do that is the point. we cant immediately cut down our energy usage and run into an energy shortage. Can we find out an alternative way to conserve this fossil fuels? Yes we can. We here, in this project suggest a few ways to conserve conventional energy by making using of available renewable resources and biomass. We further extend our project by suggesting more reliable applications which can make use of both renewable and conventional sources for efficient management. These types of systems are known as HYBRID SYSTEMS. If we are able to develop these systems in a way such that these get employed into every appliance we use and also into transport we can achieve our objective of conserving fossil fuel. As of now we cannot make use of these systems in industries and other large scale energy consuming units as these methods are not highly efficient and dont produce huge amounts of energies. So if we are able to minimize the energy consumption in domestic usage by making use of these systems, we can supply the conventional energy to the industries. As technology is ever improving we hope that efficiency of these systems get increased to an extent that the renewable sources can be employed even in high power consuming areas in near future.

1. Introduction The current global energy scenario is as shown in the figure below

Fig(1)We can see that we are mostly dependent on Fossil fuels. We are trying to improve the renewable energy production which is as low as 1% as shown in the figure, so that we can save the fossil fuels for the future generations. As this is our point of concern is that we are emphasising on the need and how we can improvise the saving of conventional resources.

Types of Non-conventional energy sources1. Solar Energy2. Wind Energy3. Hydel Energy4. Biomass5. Geo-Thermal6. Tidal and wave

In this project we will emphasize the scope of the first four sources mentioned above.

2.1. Solar Energy and its guiding parametersSolar energy offers many advantageous features over other alternative sources of energy. 2.1.1 Insolation (I)It is the quantity indicating the amount of incident solar power on unit surface area,commmanly expressed in units kW/m2.At the earths outer atmosphere ,the solar insolation on 1m2 surface oriented normal to suns rays is called SOLAR CONSTANT and its value is 1.37 kW/m2.Due to atmospheric effects, the peak solar insolation incident on terristrial sufrace oriented normal to sun at noon on a clear day is on order of 1kW/m2.A solar insolation level of 1kW/m2 is often called PEAK SUN.The graph shown gives the amount of power present in different wavelengths of radiation.It can be seen from the graph that 50% of solar energy is in the form of thermal energy.solar photo voltaic (PV) captures the energy in visible region.solar thermal captures energy in infrared region.

Fig(2)2.1.2 Irradiance (H)It is the amount of solar energy received on unit surface expressed in units kWh/m2.The relation between solar insolation and solar irradiance is that the solar irradiance is essentially solar insolation intergrated with respect to time.When solar irradiance data is representedon an average daily basis ,the value is often called PEAK SUN HOURS(PSH) and can be thought of as the number of equivalent hours/day that solar insolation is at its peak level of 1kW/m2.The plot of irradiance as a function of the year is shown in the figure below

Fig(3)We can see that the level varies with day of the year. It may reach a peak some day of the year and reach a bottom on some other day of the year. The peaks and valleys are the diret result of the amount of irradaince reaching the earth.

Fig(4)

2.2 Types of solar thermal power plants

The two main types of solar thermal power plants are1. Concentrating Solar Power(CSP) plants2. Solar Chimneys2.2.1.1 Concentrating Solar Power (CSP) plantsSolar thermal power plants generally use reflectors to concentrate sunlight into a heat absorber.such power plants are known as Concentrating Solar Power(CSP) plants.CSP plants produce electric power by cinverrting the suns energy into high-temperature heat using various mirror configurations.The heat is then channeled through a conventional generator to generate electric power.The plants consist of two ports,one that collects solar energy and converts it to heat,and another that converts heat energy to electricity.Concentrating solar power systems can be sized for village power (10 kilowatts) or grid-connected applications (up to 100 megawatts). The amount of power generated by a concentrating solar power plant depends on the amount of direct sunlight. Like concentrating photovoltaic concentrators, these technologies use only direct-beam sunlight, rather than diffuse solar radiation.

2.2.1.2 Types of CSP plants

2.2.1.1.1Parabolic Trough SystemsThe suns energy is concentrated by parabolically curved, trough-shaped reflectors onto a receiver pipe running along the inside of the curved surface. This energy heats oil flowing through the pipe and the heat energy is then used to generate electricity in a conventional steam generator. This configuration enables the single-axis troughs to track the sun from east to west during the day to ensure that the sun is continuously focused on the receiver pipes. Individual trough systems currently can generate about 80 megawatts of electricity.

Fig(6)

2.2.1.1.2 Power Tower SystemsA power tower converts sunshine into clean electricity for the electricity grids. The technology utilizes many large, sun-tracking mirrors (heliostats) to focus sunlight on a receiver at the top of a tower. A heat transfer fluid heated in the receiver is used to generate steam, which, in turn, is used in a conventional turbine-generator to produceElectricity. Early power towers utilized steam as the heat transfer fluid; current designs utilize molten nitrate salt because of its superior heat transfer and energy storage capabilities. Individual commercial plants will be sized to produce anywhere from 50 to 200 MW of electricityfig(7) 2.2.1.1.3 Parabolic Dish SystemsParabolic dish systems consist of a parabolic-shaped point focus concentrator in the form of a dish that reflects solar radiation onto a receiver mounted at the focal point. These concentrators are mounted on a structure with a two-axis tracking system to follow the sun. The collected heat is typically utilized directly by a heat engine mounted on the receiver moving with the dish structure. The modules have max sizes of 50 kW and have achieved peak efficiencies up to 30% net.fig(8)

2.2.1.1.4 Solar chimneyA solar chimney is a solar thermal power plant where air passes under a very large agricultural glass house (between 2 and 30 kilometres in diameter). The air is heated by the sun and channelled upwards towards a convection tower. It then rises naturally and is used to drive turbines, which generate electricity. A solar chimney is an apparatus for harnessing solar energy by convection of heated air. In its simplest form, it simply consists of a black-painted chimney. During the daytime, solar energy heats the chimney and thereby heats the air within it, resulting in an updraft of air within

Fig(9)the chimney.

2.3Applications2.3.1 Water heating Water heating is required in most countries of the world for both domestic and commercial use. The simplest solar water heater is a piece of black plastic pipe, filled with water, and laid in the sun for the water to heat up. Simple solar water heaters usually comprise a series of pipes, which are painted black, sitting inside an insulated box fronted with a glass panel. This is known as a solar collector. The fluid to be heated passes through the collector and into a tank for storage. The fluid can be cycled through the tank several times to raise the heat of the fluid to the required temperature.

2.3.2 Thermosyphon systemThe thermosyphon system makes use of the natural tendency of hot water to rise above cold water.

Fig(10)The tank in such a system is always placed above the top of the collector and as water is heated in the collector it rises and is replaced by cold water from the bottom of the tank. This cycle will continue until the temperature of the water in the tank is equal to that of the panel. A one-way valve is usually fitted in the system to prevent the reverse occurring at night when the temperature drops. As hot water is drawn off for use, fresh cold water is fed into the system from the mains.2.3.3 Limitation As most solar collectors are fitted on the roofs of houses, this system is not always convenient, as it is difficult to site the tank above the collector, in which case the system will need a pump to circulate the water.2.4 Pumped solar water heatersPumped solar water heaters use a pumping device to drive the water through the collector. Often the fluid circulating in the collector will be treated with an anti-corrosive and /or anti-freeze chemical.In this case a heat exchanger is required to transfer the heat to the consumers hot water supply. In this system we can also embed a conventional heating mechanism which can be used during cloudy weather or during night.

2.4.1 Key featureThe major advantage of this system is that the storage tank can be sited below the collector.2.4.2 Disadvantage The disadvantage is that electricity is required to drive the pumpTherefore,a suitable trade-off has to be made between the two while choosing this system Fig(11)2.5 Solar District HeatingIf an entire housing estate should be fitted with solar systems, one solution is a solar district heating system. The collectors are either distributed on the houses, or replaced by a large, central solar collector. The collectors then heat up a big central storage tank, from which much of the heat is distributed back to the houses. The surface-to-volume ratio of a central storage tank is much better than that for distributed storage systems, so the storage losses are much lower, and even permit seasonal heat storage. Solar district heating is also an option if room heating is to be covered by solar energy.Solar geysers can easily be installed in group houses and apartments, especially during construction, if adequate provisions are made for piping, collector assembly and cold-water supply. Proper load matching is required to ensure that the capacity of the system installed is optimized to meet the daily hot water needs of the end-user.

Fig(12)2.6.1 Cost Benefit of Solar Water Heating SystemThe most cost-effective way to install a solar geyser is to integrate the collector assembly, cold-water supply and piping with the design of a new house under construction. 2.7 Solar DryerControlled drying is required for various crops and products, such as grain, coffee, tobacco, fruits vegetables and fish. Their quality can be enhanced if the drying is properly carried out.Solar thermal technology can be used to assist with the drying of such products.

2.7.1 WorkingThe main principle of operation is to raise the heat of the product, which is usually held within a compartment or box, while at the same time passing air through the compartment to remove moisture. The flow of air is often promoted using the stackeffect which takes advantage of the fact that hot air rises and can therefore be drawn upwards through a chimney, while drawing in cooler air from below. Alternatively a fan can be used.

Fig(13)

Solar dryer is very useful device for1. Agriculture crop drying2. Food processing industries for dehydration of fruits, potatoes, onions and other vegetables3. Dairy industries for production of milk powder, casein etc.4. Seasoning of wood and timber5. Textile industries for drying of textile materials.

2.7.2 Practical Implementation1. The first concentrated solar power plant to be built primarily with Siemens components has been constructed in Lebrija, a village located approximately 60 kilometers south of Seville, Spain. Built on sun-drenched land formerly used for growing cotton, the Lebrija power plant is to supply approximately 50,000 homes in the region with environmentally friendly Solarpower. The solar field includes nearly 6,000 parabolic collectors, 18,000 solar receivers and more than 150,000 parabolic reflectors.

Fig(14)

2. In India, Tirumala, the most famous temple towin in Andhrapradesh is relying entirely on clean energy to feed over 70,000 people every day. The temple has installed solar powered lights; solar cooking system, windmills and a water recycling station. From gardening to cooking, only non-conventional sources of energy are now being used in the temples of Tirupati. The temple has installed solar powered lights, solar cooking system, windmills and a water recycling station. "The basic principle is conversion of water into steam energy. The water flows through the pipes and the solar dishes concentrate the solar energy to the concentrators. In the concentrators the water is converted into steam and that steam is utilised for cooking.

Fig(15) The entire roof top in tirumala fitted Parabolic-dish type solar harvesting systemThe system designed to produce over 4000 kgs of steam/day at 180C and 10 kg is adequate to cook two meals for approximately 15,000 persons. Its installation was accomplished in September 2002 and was launched on 11th October 2002. Its cost is just Rs.1 crore 8 years ago. To set up the system of 106 solar dishes that use solar energy to convert water into steam, which is then used for all the cooking. It saves Tirupati 1.2 lakh litres of diesel every year. Nearly 50,000 kilos of rice along with sambhar and rasam are cooked in the kitchens of Tirumala every day of the year without using conventional gas. Instead it's the steam produced by the non-conventional solar cooking system that reaches the kitchen through the pipes that's used for cooking.

Fig(16)TTD's requirements per year are 350 lakh units out of which 147 lakh units are produced from non-conventional energy sources This means that 40-45 per cent of the energy required by TTD is coming from its non-conventional sources. Tirumala also has a water recycling station that purifies all waste water which is then re-used in the temple city's gardens. Even the street lamps going up the Tirumala hill are solar powered. With even the temples now going green perhaps it is time for humans to follow.

2.8 Passive solar buildings for cold areas of the Himalayan Range

Fig(15)

Inpassive solar building design, windows, walls, and floors are made to collect, store, and distributesolar energyin the form of heat in the winter and reject solar heat in the summer. The concept used is Passive solar architecture Passive solar architecture is the way to construct a building so that its structure benefits as much as possible from the external climate to make the interior space as comfortable as possible. A passive solar building is an insulated building with a high thermal mass coupled with a solar gain component. It is built along an east-west axis. The solar radiations are collected through the south face and trapped inside trough the glazing, greenhouse or any other passive solar component. This heat is stored during the day inside the walls and released during the night to maintain the atmosphere warm.

As the thermal efficiency of a passive solar building depends on the quality of the construction, some skilled mason and carpenter have been trained the local and international NGOs. The over-cost of the passive solar components is 10 to 20% of the building investment. But no running costs are required and the maintenance is cheap and easy.2.8.1 Practical implementationThe passive solar technology have been implemented in many areas, some examples are:This technology has been implemented in more than 20 schools by the Leachy govt. The over cost of passive solar component is between 20, 000 Rs to 40, 000 Rs per classroom. It has been implemented in Administration buildings of Ladakh Autonomous Hill Council

Fig(16)

In maternity wards and operating theatres, the passive solar technology can be combined with a radiant floor heating to optimize the hygiene condition.

China's first building passive solar heating room Minqin County in Gansu Province in 1977 completed the majority of scientists through 20 years of efforts

3.WIND ENERGYwind is by-product of solar energy. This can be explained as wind is a result of difference in temperature at two different places which causes air to flow from one place to another. Thus it becomes a by-product of solar energy. Approximately 2% of solar energy is useful in producing high winds which are useful in production of wind energy. atmospheric pressure zones are created because of this effect and results in air flow from high pressure areas to low pressure areas. To use the energy from the wind to rotate a fan like structure helped us to make use of that energy. Those fan like structures are called wind mills and they date back to more than 600 years back. Typical windmill looks like as shown in the figure().

Fig(17)Wind is unpredictable like weather. It varies from place to place and moment to moment. It is a diffused enery source that cannot be containned or stored for use elsewhere or after some time.3.1 CLASSIFICATIONWind mills are classified into two types: Horizantal axis and Verical axis. 3.1.1 HORIZANTAL AXISHorizantal axis type windmills have their blades rotating on an axis parallel to the ground. This is most common wind turbine design. The axis of blade is parallel to the wind flow. These have 35%efficiency and farm mills of this type have 15% efficiency.

Fig(18)3.1.2 VERTICAL AXISThese are not as common as horizantal type wind mills. These have existed for centuries. These are less efficient compared to horizantal type. these are only 30% efficient. Vertical axis of blade has to be oriented with respect to wind direction. But these have an advantage of lower tower cost for installation. Only problem is that these are less efficient at collecting energy from wind.

Fig(19)

Fig(20)

There is one more type of windmill called cyclo-gyro windmill with very high efficiency of 60%. However these are very sensitive to wind direction and these are not very stable. These are also very complex to build.Fom fig(20) we can notice the different types of wind mills which are mentioned above.3.2MAIN COMPONENTS OF WIND MILL1) Rotar2)Drag design3) Lift design4) Tip speed ratio 5)Generator6)Transmission7) TowerThe following fig(21) shows all the components of a windmill.

Fig(21)3.1.2 ROTARThis portion collects the energy from wind. This generally consists of two or more blades made up of metal, of fiberglass or wood, based upon nessecity and economy. The rotation of this is determined by wind speed and shape of the blades. This rotar is connected to the shaft of the generator.

DRAG DESIGN and LIFT DESIGN and TIP SPEED RATIO are not being explained by us as this is not a technical report

3.1.3 GENERATORAs mentioned the rotar is connected to the shaft of the generator and this the component which produces electrical energy. The rotating shaft in magnetic field causes current generation and which inturn is used by us.It is very important to choose correct type of generator. most of the appliances need 240V, 50Hz supply. So we have to choose a generator which can produce these values even when wind is fluctuating. We can go for another method where the energy is stored in batteries and using an inverter this is converted into ac and can be used by us.

3.1.4TRANSIMMISIONThe number of revolutions per minute (rpm) of a wind turbine rotar can range between 40 rpm and 400rpm depending on the model and the wind speed. These require a gearbox transmission to increase the rotation of the generator to the speeds necessary for efficient electricity production. 3.1.5 TOWERTower is not just a supporting structure. Based on wind range the tower hieght is selected.most commonly the height will vary from 40 to 70 metres. Towers must be strong enough to support the wind turbine and to sustain vibration, wind loading and the overall weather elements for the lifetime of the wind turbine. Their costs will vary widely as a function of design and height.

the above fig(22) shows the graph plotted between wind speed and power density

The above tabular column(1) gives us the idea of parameters varying with respect to wind speed.

Having discussed about various parameters and construction of wind mills let us see where all we can install these wind mills in india. This mainly depends on where wind energy is more. Let us see various wind energy sites in India. Here it is measured in terms of potential to produce energy and the tabular column will explaiin these

Table(2)These are the major states which produce wind energy and the below one shows the minor portion and also overall production.

1West Bengal 450 1.1 450

2Others 2990 3.1 -

Total (All India) 45195 2884.75 12875

Table(3)pictorically we can represent as below

Fig(23)Till now we have seen where all wind is produced in large quantities now let us see what all can we do with this wind energy.3.2 APPLICATIONS: We can use these wind mills which rotate to take water from wells. This can be done by converting ossible motion of windmill into linear movement of the rope which is tied to the pot that brings water from the wells. We can also use these in hybrid sysytems as non-conventional energy source so that the usage of conventional energy can be reduced. We can use these windmills to rotate huge turbines if the wind has more speed and generate electricity from them. But this is not practically ossible as the wind wont have that energy. So this is used only in small scale energy production. 3.3 LIMITATIONS- Efficiency is very less ie.,30%- Wind wont be constant - It is not available everywhere in sufficient amounts, so not applicable in all places.- It would not be reliable where continuous energy is required.-It would not be reliable for using solely without other conventional sources as backup.

4.HYDRO ELECTRIC POWER (HYDEL POWER)4.1Operating principleHydro-electric principle is generated by the flow of water through turbine, turning the blade of the turbine. A generated shaft connected to this turbine also turns and hence generates electricity.The main components of a hydel power plant are:1. Dam/Reservoir/Large buffer tank2. penstock3. powerhousea. Turbinesb. Generatorsc. Step-up Transformers

Fig(24)

Depending on the capacity, hydel power plants are divided into the following categories:

Category Capacity Application

Large Hydel Plant 50 MW to 1000 MW Large Cities

Small Hydel Plant 1 MW to 50 MW Small cities to Towns

Mini Hydel Plant 100 kW to 1000 kW Towns

Micro Hydel Plant < 100 kW Rural community

Pico Hydel Plant < 5 kW Individual home

Table(4)Hydel plants have an efficiency of 75%.4.2 Hydraulic Energy The power that is obtainable from a stream depends primarily on two factors. They are, 1. Head 2.Flow 4.2.1 Head The head is the vertical height from the top of the penstock to the bottom of the penstock.Larger the head, higher will be the speed of the turbine and larger will be the power output.4.2.2 FlowThe flow is the volume of water which flows in one second.4.2.3 Layouts As the physical layout of the micro hydel plant will affect the power output, cost, ruggedness etc., it is worth to consider the following options in choosing the plant layout.4.2.4 Locations of homes: The distance of the homes from the micro hydel plant will affect the cost of the overall plant. 4.2.5 Power generation: The generated power depends on the head and flow of the water. These are both affected by the physical layout.4.2.6 Cost:The major cost factor in the plant is the penstock and the distribution system. The challenge is to keep the penstock and distribution system as short as possible. Both the cost and the losses increases as these become longer.4.2.7 Site Survey It is important to measure the head and the flow with reasonable accuracy to ensure that the power requirements are met. It is better to under estimate the head and the flow rather than to overestimate them to obtain conservative hydraulic power capability of the stream.4.3 Turbine The turbine is a device which converts the hydraulic power from the water to rotating mechanical energy. There are several turbines that have been developed for specific purposes. Turbines are classified into 1.Impulse turbines for high heads. 2. Reaction turbines for low heads. 3.Submersible propeller turbines. Some of the turbines are Elton, cross flow, turbo, Francis, Harris etc.

Fig(25)4.4 Generator Generally, induction generators and synchronous generators are used to produce the power. The three phase induction motors can be used as generators. These are easily available and quite inexpensive. For most home applications, a single phase supply is required. It is required to produce a single phase supply from a three phase motor.4.5 Load Control The speed of the turbine changes when the load connected to the generator changes. Since this change of speed affects the voltage and frequency, the load on the generator must be kept constant or the flow of water through the nozzle must be adjusted. The unused power of the induction generator is sent to a ballast or dummy load so that the total load on the generator remains constant. For example if the generator produces 1000W and the total load connected is 700W, then the remaining 300W will be dissipated in the ballast load.

Below figure shows the location of hydro power plants in India

Fig(26)

Some of the major hydro energy generators in India:

Fig(27)

But this is at powerplant level generation of hydroelectric power .We can also do it at the domestic level by using Micro Hydel Turbines4.6 Micro Hydel TurbinesMicro Hydro Turbines available from 1KW to 30KW are useful in generating power in two different applications.Micro hydro turbines canbe installed in tall buildings in the urban setting to generate power. Water following down from the rooftop water tank can be capitalized to install hydro turbines and generate power for at least 4-5 hours/ day during the morning and evening hours. Note that hydro turbines generate power at 80-85% efficiency compared to 15-20%for Wind Turbines and Solar PV Systems. Hence this is useful energy which can be consumed in the common areas for lighting, CCTV, Wi-Fi, etc.

Fig(28)The entire mechanism is clearly described in the video at www.youtube.com/watch?v=h25oVvrEpAI5.Biogas5.1Biogas-Fuel to futureBiogas is clean environment friendly fuel that can be obtained by anaerobic digestion of animal residues and domestic and farm wastes, abundantly available in the countryside. Biogas is an important renewable energy resource for rural areas in India Biogas generally comprise of 55-65 % methane, 35-45 % carbon dioxide, 0.5-1.0 % hydrogen sulfide and traces of water vapor. Average calorific value of biogas is 20 MJ/m3 (4713 kcal/m3).Biogas like Liquefied Petroleum Gas (LPG) cannot be liquefied under normal temperature and pressure. Critical temperature required for liquefaction of methane is -82.1oC at 4.71MPa pressure, therefore use of biogas is limited nearby the biogas plant. An estimate indicates that India has a potential of generating 6.38 X 1010 m3 of biogas from 980 million tons of cattle dung produced annually. The heat value of this gas amounts to 1.3 X 1012 MJ. In addition, 350 million tons of manure would also produce along with biogasTypical biomass fuels include a wide variety of material. Some common fuels are forestry by-products, agricultural wastes, municipal wastes, and syngas.

Fig(29). There are also many next-generation biomass feedstocks in different stages of commercialization. These new fuels have the potential to dramatically scale plant sizes and the feedstock supply chain, creating significant opportunities for additional generation fleet expansion.5.2Environmental Benefits5.2.1 Combined Heat and PowerCombined heat and power generation, also known as cogeneration, is used for many different purposes. Harnessing heat created by power generation increases plant outputs, reduces fuel consumption, and creates another valuable commodity which can improve plant economics. Whatever the application of a cogeneration system might be, efficient conversion of waste heat into a commercial resource is a critical necessity.

5.2.3 CO2 and Emissions ReductionBiomass generation is known to be a carbon-neutral power source and is being adopted as an important alternative to fossil fuel baseload generation. Using a highly efficient Siemens turbine can create additional long-term environmental advantages for industries and electricity generators seeking to further decrease their carbon and emissions footprints. Less fuel consumption over a plants lifetime due to industry-leading efficiency results in significant cost savings and fewer system pollutants, compared to less efficient machines.5.3Special features of Biogas engine5.3.1Saving diesel :- can replace 80% diesel. For example consider 5 hp engine running daily 8 hours on biogas & normal specific fuel consumption 175 gms/bhp- assuming 25 days per month operation. Then 42 lit. diesel will be required and about 168 lit.of diesel per month will be saved. 5.3.2Monthly savings168 lit. @ 50.00 Rs/lit. = Rs.8400 or equivalently Rs. 1,00800 per year.5.3.3Exhaust smoke density - is less when run on biogas .5.3.4Exhaust gas temperature- remains almost the same.5.3.5 Engine deposits generally cleanliness of engine with biogas is better than the diesel operation.

Fig(30)

Fig(31)5.4 Dedicated Biomass Power StationsThe location of a biomass plant used for electricity production is usually dependent on the regional availability of feedstock. The size of dedicated biomass power stations is also often driven by local biomass availability. Transport costs of the usually bulky fuel play a major role in the plants economics. Rail and especially water shipping has reduced transport costs significantly, which has led to the development of a global biomass market. As the market for commoditized biomass fuels expands so will the expansion of centralized biomass electricity production fleets.

Fig(32)

Fig(33)6.Q&A

The chefs say that it takes less than 20 minutes to cook an entire meal. No wonder that this system is the chefs favourite "Since we started using this system, our work is easier and quicker. It's much better than gas which took much longer. We've been using this for more than 8-9 years and we are really comfortable with it. It is not just the sun alone as Tirumala uses wind and water effectively too. The windmills on the hill ensure that the temple town is able to meet a some part of the power requirement by itself.