Non-conventional Energy sources

The sources of energy which are exhaustible and being produced continuously in nature are called nonconventional energy or renewable sources of energy. Some of these sources include solar energy, wind energy and tidal energy. The conventional energy sources are basically based on fossil fuels which have finite reserves in nature and hence would become extinct in future. Since the development and progress of mankind are closely related to energy sources, many countries throughout the world have engaged themselves in searching and developing non-conventional energy sources that would be very essential to sustain the life cycle of human being.The conventional sources of energy are generally nonrenewable sources of energy, which are being used since a long time. These sources of energy are being used extensively in such a way that their known reserves have been depleted to a great extent. The sources of energy which are being produced continuously in nature and are inexhaustible are called nonconventional energy (or) renewable sources of energy. Figure 1 provides the pictorial views of different forms of non-conventional energy sources and renewable energy sources options, respectively.

Different non-conventional sources that UBHAVA focusses:-

Solar energy

Solar energy is the most readily available and free source of energy since prehistoric times. It is estimated that solar energy equivalent to over 15,000 times the world's annual commercial energy consumption reaches the earth every year. Solar energy can be utilized through two different routes, as solar thermal route and solar electric (solar photovoltaic) routes. Solar thermal route uses the sun's heat to produce hot water or air, cook food, drying materials etc. Solar photovoltaic uses sun's heat to produce electricity for lighting home and building, running motors, pumps, electric appliances, and lighting. In solar thermal route, solar energy can be converted into thermal energy with the help of solar collectors and receivers known as solar thermal devices.

Wind energy

Wind energy is basically harnessing of wind power to produce electricity. The kinetic energy of the wind is converted to electrical energy. When solar radiation enters the earth's atmosphere, different regions of the atmosphere are heated to different degrees because of earth curvature. This heating is higher at the equator and lowest at the poles. Since air tends to flow from warmer to cooler regions, this causes what we call winds, and it is these airflows that are harnessed in windmills and wind turbines to produce power. Now wind power is harnessed to generate electricity in a larger scale with better technology.

Bio energy

Bio-energy, in the form of biogas, which is derived from biomass, is expected to become one of the key energy resources for global sustainable development. Biomass is a renewable energy resource derived from the carbonaceous waste of various human and natural activities. Biomass does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon in growing as it releases when consumed as a fuel. Its advantage is that it can be used to generate electricity with the same equipment that is now being used for burning fossil fuels. Bio energy is being used for cooking, mechanical applications, pumping, power generation etc.

Hydro energy

The potential energy of falling water, captured and converted to mechanical energy by waterwheels, powered the start of the industrial revolution. Wherever sufficient head, or change in elevation, could be found, rivers and streams were dammed and mills were built. Water under pressure flows through a turbine and causes it to spin. The Turbine is connected to a generator, which produces electricity.

Ocean energy

The ocean contains two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves. Ocean thermal energy is used for many applications, including electricity generation. There are three types of electricity conversion systems: closed-cycle, open cycle, and hybrid. Closed cycle systems use the ocean's warm surface water to vaporize a working fluid, which has a low boiling point, such as ammonia. The vapour expands and turns a turbine. The turbine then activates a generator to produce electricity. Open-cycle systems actually boil the seawater by operating at low pressures. This produces steam that passes through a turbine / generator. The hybrid systems combine both closed-cycle and open-cycle systems. Ocean mechanical energy is quite different from ocean thermal energy. Even though the sun affects all ocean activity, tides are driven primarily by the gravitational pull of the moon, and waves are driven primarily by the winds. A barrage (dam) is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator.

Energy from Wastes

An estimated 50 million tons of solid waste and approximately 6,000 million cubic meters of liquid waste are generated annually in the urban areas of India. In India, there is a great potentiality of generating approximately 2,600 MW of power from urban and municipal wastes and approximately, 1,300 MW from industrial wastes, respectively. A total of 48 projects with aggregate capacity of about 69.62 MW ex. have been installed in the country thereby utilizing only 1.8% of the potential that exists.