Author – Kamal Chaturvedi
More than 200 million people live in rural areas of India without any access to grid-connected power. While the Indian government has taken up the task of rural electrification on a warpath, it has long way to go since over 18,000 villages are un-electrified during FY2016. The huge cost involved in installing and servicing of power transmission lines is the main reason for this problem, while heavy transmission and distribution losses and poor power reliability are other issues aggravating the problem.
Hence, we need to look for alternative forms of energy to electrify our villages, which has led to the promotion of solar photovoltaic and wind power generation systems at a large scale. However, these standalone systems are not sufficient enough to provide stable electricity round the year, because of changing weather conditions. Solar energy is mostly available in the day-time, that too in summers, while wind energy is available only intermittently.
According to Bridge to India’s report, India is set to become the fourth largest solar market globally in 2016, with an estimated 6.6GW solar power generation capacity already installed. Similarly, the installed capacity of wind power in India is about 23,400MW by the end of FY2015. Hence, with both the renewable energy resources readily available, we can utilize a solar-wind hybrid system for residential and commercial purposes.
Creating a hybrid model of solar and wind power can be ideal for rural implementation, since it integrates the capabilities of both the systems to provide uninterrupted electricity. Particularly in rural areas where electricity requirement is low, we could utilize this energy to store electricity in batteries, which can serve as a backup when the conventional power supply goes down.
Components of Solar-Wind Hybrid System
|Operation||Produce electric current directly from sunlight||Kinetic energy of wind turbine drives the generator||Combination of both|
|Technical Specifications||Rated Power 10W|
Operating Voltage 17V
Operating Current 0.59A
Open Circuit Voltage 21V
Short Circuit current 0.61A
|Start Wind Speed 5.6km/h|
Rated Voltage 12V
Wind turbine Material- Galvanized Iron
No. of wings 8
Safe wind speed 50 km/h
|Average Life||25 years||10 years||Average of both|
|Initial Investment||150-200/Wp||45,000/kW||Calculated Below|
A typical solar-wind hybrid model tries to utilize the intermittent energy coming from solar and wind energy units and provide a steady supply of power. The motion of the wind-turbine leads to mechanical energy in the rotor of the Aero-Wind generator which converts it into electricity. While the solar panel in the system converts the daylight directly into electricity. The MPPT Controller regulates the energy coming from the panels and ensures a continuous high power generation.
The solar-wind hybrid system is made up of the following components:-
- Solar Photovoltaic panels collect the sun’s radiation whenever it falls on them and which they convert it to Direct Current output.
- Mini Wind Turbine is installed on top of a tall tower or placed in open fields to collect kinetic energy from the wind whenever it blows.
- Aero-Wind Generator converts kinetic energy of the wind turbine into electricity and controls the input.
- Battery Bank – A combination of multiple batteries are connected together to create one large battery bank of required voltage and ampere-hour capacity
- Maximum Power Point Tracking Controller (MPPT) is an electronic power converter that optimizes the power coming from the solar panels and wind generators and matches it to the capacity of the battery bank. MPPT converts the higher DC voltage output from wind turbine and solar panels down to the lower voltage needed to charge the batteries
- PV Panel Trackers on which the solar panels are mounted to follow or track the movement of the sun for maximum sunlight
- Inverter converts the DC power received from the panels or the generator into AC power to be supplied to homes or offices
- Solid State Relays (SSR) – They are the combination of a transistor with low operating power and low triggering voltage, which connected to the input of the system, and another transistors with high operating power and low triggering voltage.
Typically we have to measure the complete lifecycle cost of a solar-wind hybrid system, since that is the total cost of the initial capital investment, operational, maintenance and battery replacement costs.
If we take an example of a residential house in India, it will have 4-5 tubelights or CFLs, 2-3 Fans, 1 TV or computer and a 0.5HP motor as the typical connected load. The total power consumption of the house can be calculated to be around 1600-1800 WH or 1.8 units/day.
Consider an approximate power consumption of 1.8 units/day. In remote villages, the cost turns out to be around INR23/unit consumed.
Monthly cost = 1.8units x 30days x 23= INR1,242.00
Annual bill = 1,242 x 12= INR14,904
Most of this cost is subsidized by the Government of India, since villagers cannot afford this cost.
On this basis, we have calculated the cost for the solar-wind hybrid system. This comparison shows that solar-wind hybrid systems can be cost effective for villages as they are one-time investment for getting uninterrupted power:
|Cost of Solar-wind hybrid system|
|Solar watt capacity –||1.8 units of power|
|Solar panel area –||1.8 units of power|
|(1.8kwh/7hr) x 1.25 =||0.32units/day|
|Solar panel cost –||INR48,000|
|Wind power generation –||1.5units/day|
|Wind system cost –||INR67,500|
|Two lead acid batteries –||INR16,000|
|Installation and civil works –||INR18,000|
|Total cost –||INR1,66,500|
Solar-wind hybrid systems are yet to become popular in India, since the market awareness is low and the initial capital investment is high. If a house doesn’t receive an adequate amount of wind or sunlight, there is no point in installing a hybrid system. Further, the terrace has to large enough to provide space on the ground for setting up panels and wind turbines. Consumers are skeptical about feasibility of the hybrid system, when it accounts for such high initial investment and hence, the Indian government has to take the lead in setting them up for rural households.
- Currently, very few businesses are involved in designing, manufacturing and supplying highly efficient solar-wind hybrid systems:
- SU Solartech Systems: Leading manufacturer of different types of PV Systems, solar thermal systems, SWEG, energy saving and security devices, etc.
- SIKCO – Society for Innovative Knowledge & Cost Optimization: It is the most integrated company in renewable energy sector in India, producing products like Solar, Wind and Biogas powerplants.
- Other companies include Shantee Power, Saee Power, Soyo Systems, Prolight Systems etc. to name a few.