Non-conventional energy sources are renewable or alternative forms of energy that are not as widely used as traditional fossil fuels such as coal, oil, and natural gas. As the world faces the challenges of climate change and the depletion of fossil fuels, these sources — including tidal, wave, solar, geothermal, and biomass energy — are becoming increasingly important for a sustainable future.
Tidal energy is a form of hydropower that converts the energy obtained from the rise and fall of ocean tides into electricity.
Cause: The gravitational pull of the Moon (and to a lesser extent, the Sun) causes the sea level to rise and fall, creating high and low tides, typically twice a day.
Method of Harnessing: A dam or barrage is built across an estuary or a bay with a large tidal range.
Some modern systems can also generate electricity from the incoming tide, making them more efficient.
Significance: Tidal power is predictable and reliable but is limited to coastal areas with a significant tidal range.
Wave energy is derived from the motion of ocean surface waves, which are primarily caused by wind blowing over the water.
Method of Harnessing: There are many designs for wave energy converters. One notable invention is Salter's Duck.
Salter's Duck: This device consists of a teardrop-shaped float (the "duck") and a connected, more stable balance float. As waves pass, they cause the duck to rock up and down relative to the balance float. This relative motion powers a pump or generator to produce electricity.
Significance: The oceans contain a vast amount of energy in the form of waves. While the technology is still developing, wave power has the potential to be a significant source of renewable energy for coastal communities.
Solar energy is the radiant light and heat from the Sun harnessed using a range of technologies. It is the most abundant renewable energy source available on Earth.
Solar Constant: The amount of solar energy that reaches the top of the Earth's atmosphere is about .
Surface Intensity: After passing through the atmosphere (which reflects and absorbs some energy), the intensity at the Earth's surface on a clear day is about .
Solar energy can be utilized in two main ways:
This technology uses sunlight to create heat.
Photovoltaic (PV) cells convert sunlight directly into electricity.
Mechanism: Solar cells are made of semiconductor materials (usually silicon). When photons strike the cell, they energize electrons, allowing them to flow and create an electric current.
Solar Panels: A single solar cell produces a very small voltage (~0.5 V). Many cells are connected in series (to increase voltage) and in parallel (to increase current) to form a solar panel.
Energy Storage: Since solar panels only work during the day, electricity can be stored in Nickel-Cadmium (Ni-Cd) batteries for use at night or on cloudy days.
Applications: Solar cells power small devices (calculators), large-scale power plants, satellites, and remote installations.
Energy from the heat stored within the Earth is known as geothermal energy. This includes energy from hot springs, geysers, and hot rocks.
Biomass is organic material that comes from plants and animals. It contains stored energy from the Sun captured through photosynthesis.
| Energy Source | Origin | Method of Harnessing |
|---|---|---|
| Tidal Energy | Gravitational pull of the Moon and Sun | Dams (barrages) that use the rise and fall of tides to turn turbines |
| Wave Energy | Wind blowing across the ocean surface | Devices (like Salter's Duck) that convert wave motion into electricity |
| Solar Energy | Nuclear fusion in the Sun | Thermal: Heat for warming or steam generation. Photovoltaic: Converting sunlight directly into electricity |
| Geothermal | Radioactive decay and primordial heat within Earth | Steam from hot rocks/springs drives turbines |
| Biomass | Solar energy stored in organic matter | Combustion, fermentation, or anaerobic digestion |