Alternative Energy & Sources

• Alternative energy sources include solar, wind, hydropower, tidal power, geothermal, biofuel, and biodiesel

Energy Sources - Indian Scenario (2003)

• Primary energy sources in India in 2003 consisted of coal (53%), natural gas (8%), oil (33%), nuclear (5%), and hydro (1%).

Solar Energy

• Solar power heats water to form steam, which generates electricity similarly to fossil fuel or nuclear plants
• Solar energy does not release air pollutants
• Solar energy does not generate electricity at night but can work on cloudy days
• The benefits of solar power include abundance, no greenhouse gases, simplicity, minimal repair needs and low-cost over the long term
• Solar energy provides cheap, clean, and inexhaustible energy to small villages, domestic establishments, and small-scale industries
• Active solar power involves the use of technology to capture and use solar energy.
• Passive solar power involves designing buildings to take advantage of solar energy without active mechanical systems.

Wind Energy

• Wind energy can be used for mechanical tasks like pumping water
• Wind energy can generate electricity for direct use or storage in batteries
• India's wind energy potential is estimated to be about 20,000 MW, which is one-fifth of the total installed power generation capacity
• India is making rapid progress in wind energy utilization and has selected 80 sites in different states and union territories for wind power farms
• By 1993-94, the wind energy capacity was 61 MW.
• By 1994-95, the wind energy capacity was 235 MW.
• Approximately 18,000 MW remained under development and planning
• Positive effects of wind power: no greenhouse gasses, few other pollutants, cheap, abundant, simple
• Negative effects of wind power: noise and aesthetic pollution, metal blades may interfere with TV and radio reception, can kill bats and supply is erratic and irregular.

Hydropower

• Hydropower uses the energy of flowing water to drive turbines and generate electricity
• Hydropower is a clean, renewable energy resource
• Hydropower can generate electricity and do mechanical work, such as grinding grain
• Hydropower does not produce greenhouse gases,
• Initial construction to produce hydropower provides jobs
• Negative effects of hydropower: flooding, displacement of local inhabitants, local climatic changes, tectonic activity (earthquakes), loss of species, disruption of normal nutrient flow, and change of water temperature

Geothermal Energy

• The Earth's temperature increases at a rate of 20-75°C per kilometer from the surface
• Heat from the Earth is used by circulating water through pipes to raise steam and generate electricity
• Geothermal energy, if properly utilized, could provide about 2x10^18 to 20x10^18 Joules of energy per year
• A "wet system" uses heated water from belowground.
• A "dry system" sends aboveground water belowground to be heated.
• The resulting steam can be used for a number of purposes

Energy from Oceans

• The ocean produces tidal energy, wave energy and thermal energy

Tidal Energy

• Gravitational pull exerted by the sun and moon causes tides to develop
• Sea level rises and falls depending on the position of the sun and moon
• Sea level rise water may be diverted towards inshore reservoirs- driving the turbines during entry
• Sea level fall- the stored water released which drives the turbines again
• Total tidal energy potential has been estimated to be about 2x10^18 Joules per year.
• Tidal power is inexhaustible, clean, and cheap
• Tidal dams are placed across ocean inlets to harness the energy of water moving with the tides
• Positive & negative effects of tidal power are same as effects of hydropower

Wave Energy

• Air currents rubbing the ocean surface produces waves that are pushed towards the shore where their energy is dissipated as they break
• Floating propellers placed in shallow water along the shores are kept in motion by these waves.
• The kinetic energy of the floating propellers can be used to drive turbines maintained on floats or platforms erected for the purpose in shallow waters
• Wave energy will provide a cheap, clean, and inexhaustible source of energy

Thermal Energy

• Temperature differences between the upper and lower layers of seawater can be used to generate electricity, with the help of low-boiling-point working fluids like liquid ammonia or propane
• Ocean thermal energy has a huge potential for providing clean, cheap, inexhaustible energy

Biomass Energy

• Biomass based energy examples: biogas, petro plants, dendro thermal energy, and hydrogen
• Petro plants have hydrocarbons in their saps and latex
• Types of petro plants: Euphorbiaceae, Asclepiadaceae, Apocynaceae, and Convolvulaceae
• Biofuels ensure energy security and generate employment opportunities for rural masses
• Biofuels contribute to greening waste lands by plantation and promote integrated Holistic rural development
• Biodiesel is fuel from vegetable seeds/oils
• Biodiesel is non-toxic and biodegradable
• Biodiesel produces lower greenhouse gas emissions than diesel
• Biodiesel produces lower exhaust emissions
• Biodiesel has better fuel properties than diesel like cetane number, sulfur content, lubricity, flash point

Energy Crops

• Energy crops are grown specifically for their fuel value
• Examples of food energy crops are corn and sugarcane
• Examples of non-food energy crops are woody crops such as willow/poplar/switch grass.
• Perennial grasses are harvested annually after 2-3 years of growth
• Perennial grasses and trees can be grown on farmland less suitable for conventional crops
• Energy crops can complement traditional row crops with tree and grass crops on marginal farmland
• Energy crops provide land owners with options to diversify their income and opportunities with environmentally sustainable crops
• Economic and energy advantages of energy crops include rural agricultural development, domestic energy supply, high yield per unit area, high energy output/input ratios, and predictable supply
• Energy crops produce possible co-products like pulp and paper, chemicals, and forage
• Grasses are harvested once or twice annually and trees are harvested on 3-10 year cycles
• Environmental benefits from energy crops include improved water quality, wildlife habitat, stabilization of riverbanks, improved fish and streamside habitat, relatively low inputs of fertilizers, herbicides and pesticides, and environmental sustainability

Dendrothermal Energy

• Denuded waste lands can grow fast-growing shrubs and trees with high calorific value
• Wood, charcoal, fodder that is produced gasification systems can be used where fuel-wood and charcoal is not convenient
• Baggasse (pulp and waste from sugarcane after juice expulsion during the manufacture of sugar) can generate energy for local use

Biomass Energy Pros & Cons

• The pros of biomass are the burning of waste gets rid of solid waste, creates energy and creates new markets for crops
• The cons for biomass are the burning releases CO2 and other gasses, and creates solid waste from ash while potentially causing more grasslands