It's certainly clear that fossil fuels are mangling the climate and that the status quo is unsustainable. There is now a broad scientific consensus that the world needs to reduce greenhouse gas emissions more than 25 percent by 2020 -- and more than 80 percent by 2050. Even if the planet didn't depend on it, breaking our addictions to oil and coal would also reduce global reliance on petrothugs and vulnerability to energy-price spikes.
By 2050, one-third of the world's energy will need to come from solar, wind, and other renewable resources. Who says? British Petroleum and Royal Dutch Shell, two of the world's largest oil companies. Climate change, population growth, and fossil fuel depletion mean that renewables will need to play a bigger role in the future than they do today.
There are financial, political, and technical pressures as well as time constraints that will force tough choices; solutions will need to achieve the biggest emissions reductions for the least money in the shortest time. Hydrogen cars, cold fusion, and other speculative technologies might sound cool, but they could divert valuable resources from ideas that are already achievable and cost-effective.
The sun’s energy will replenish itself every day so it wouldn’t get used up and this is clean energy, without pollution. The only disadvantage is that the sun is up only for a few hours in a day. So we have to create means of storing this energy for the hours the sun won’t be shining.
Wind power is harnessed to drive wind power generators for the production of electricity or to drive windmills which is used in different ways to do mechanical work such as grinding of whole corn to make flour in agriculture and as lumber cutter.
hydrogen is an energy carrier and must be produced from another substance. Hydrogen is not currently widely used, but it has potential as an energy carrier in the future. Hydrogen can be produced from a variety of resources (water, fossil fuels, or biomass) and is a byproduct of other chemical processes.
The most common current way of capturing the energy from geothermal sources is to tap into naturally occurring "hydrothermal convection" systems where cooler water seeps into Earth's crust, is heated up, and then rises to the surface. When heated water is forced to the surface, it is a relatively simple matter to capture that steam and use it to drive electric generators. Geothermal power plants drill their own holes into the rock to more effectively capture the steam.
Nuclear energy originates from the splitting of uranium atoms in a process called fission. Fission releases energy that can be used to make steam, which is used in a turbine to generate electricity. Nuclear power accounts for approximately 20 percent of the United States' electricity production. More than 100 nuclear generating units are currently in operation in the United States.
The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy - around 20% of Britain's needs.
Although the energy supply is reliable and plentiful, converting it into useful electrical power is not easy.
The term "biomass" refers to organic matter that has stored energy through the process of photosynthesis. It exists in one form as plants and may be transferred through the food chain to animals' bodies and their wastes, all of which can be converted for everyday human use through processes such as combustion, which releases the carbon dioxide stored in the plant material. Many of the biomass fuels used today come in the form of wood products, dried vegetation, crop residues, and aquatic plants.