WHAT IS ENERGY?
Energy is indispensable for the high standards of living of the modern society. There are two types of energy in the world: renewable energy that includes solar energy, biomass energy, wind energy, tidal energy, hydro energy and geothermal energy; non renewable energy is derived from fossil fuels such as oil, coal, natural gas and nuclear energy. Renewable energy is generated from nature like sun, wind, tides, that naturally replenish themselves and never run out. They offer an enviromentally friendly alternative to the greenhouse gas emissions and to pollution of fossil fuels. They dont release any harmfull substances on the environment, they can decrease pollution and therefore reduce the threats to our health. Unlike fossil fuels, renewable energies are endless and completely free of charge. But they have some limits on household installation because these technologies tend to be a significant upfront cost and unrealistic expense for many people. Solar and wind energy in particular are not reliable because they are intermittent. They only generate power while the sun is shining or while the wind is blowing