Using of wind power goes back to 5000 BC when Egyptians used wind to drive their boats on the Nile River. Currently, wind energy is employed to produce electricity energy at approximately 10,000MW. In fact at 0 latitude irradiation of sun are more than of other regions of the globe. Because hot air based on weight, is lighter than cold air, so it will rise and will spread to north and south of globe till 10 km altitude. Wind turbine converts wind force to electricity energy by its blades’ rotation, and the produced energy depends on the wind speed, density of air and blade rotor area. However, wind turbines cannot work in those areas of the world where wind speed is less than 1.5 m/s, so there are limitations in using wind energy.

Solar radiation can be converted to useful energy by using various technologies. Hot water can be provided by using of the collectors. Residence buildings and offices can be designed based on Passive Solar features to provide space heating and lighting requirements, which can help to enhance contribution of solar energy in the human life. Solar thermal- electric defines by since solar radiations to be concentrated by special mirrors to provide high temperature heat to produce electricity power. Solar Thermal systems include: solar hot water heating systems, solar drying, solar space heating & cooling, solar desalination, solar detoxification, solar heat pump, solar pumping, and day lighting.

Solar photovoltaic (PV) energy is defined by conversion of sunlight into electricity energy with using of photovoltaic (PV) modules. Most of the photovoltaic modules can be mounted on the facades and roofs of the buildings. Above renewable energy resources can have various advantages and disadvantages. One of the most important factors during the processes energy

conversion in terms of cost and feasibility can be more effective on the popularity in usage of the renewable energies.

Solar PV Energy is reliable, abundant, environmentally friendly, has a decentralized installation, low maintenance, clean, light weight, overlap with IC technology, long life (more than 25 years) and above of all, the majority is manufactured from silicon which is the most abundant element in the earth’s crust, and after start-up it can produce electricity in a low price. Annual Solar radiation incident at the earth’s surface is over 10000 times more than total primary global energy consumption, in other words, total primary energy consumption is less than the solar radiation incident at the earth’s surface in one hour. Rate of solar radiation depends on the latitude of sun and climate in different zones on earth. Amount of solar energy varies based on the location and season per month, and as well, amount of solar energy varies based on location.

Hydropower energy is producing energy using storage dams, run of river and pumped storage. Hydropower energy supplies 20 percent of required electricity of the world. Since the water is heated by Sun’s radiation, the water evaporates, then the formed water vapor goes back to the rivers, and the released energy of flowing water can be harnessed by a dam to produce electrical energy.

Geothermal energy is one of resources to generate electricity which is independent of the sun. There are ultimate sources of energy within our planet. The techniques employed to obtain the energy is very simple, it is like extracting oil, the hot fluid flows under earth would be pumped on the surface, afterward it is used in the heating equipment and can convert to other kinds of energies within steam turbines. However, electricity production can be more significant than hot water. By 2000, capacity of power generation in the world using of the geothermal resources had reached to 8 GW, and thermal energy was harnessed from geothermal resources was about 16 GW.

Ocean energies are categorized to wave energy, tidal energy, and ocean thermal system. Tidal energy is created by gravitational energy of the moon, sun and earth. In fact, the principle of tidal energy is based on the water wheel, and water elevation causes to low and high tides.

France and Russia produce energy of about 400 KW to 240 KW, respectively, and the production potential in the world is approximately 60 GW for generating electricity power. Wave energy is released from conversion of crashing waves’ energy to the shoreline by wind blowing. There are Just 12 types of wave harnessing systems to convert waves to the energy and still researchers are investigating to get high energy Ocean thermal systems as the biggest solar collectors on earth; which can be harnessed to produce energy. These kinds of energies have pros and cons; it depends to looming energy of oceans and seas.

Energy is derived from cellulose materials like plants to generate electrical power, and it is accessible easily. Biomass materials are classified into two main categories, first, woody biomass such as softwoods and hardwoods, which come from trees, second, Non-woody biomass such as straws, husks, pits and stalks, which are derived from agricultural residues.

Biomass energy is one kind of renewable energy because that can be a stored solar energy to reduce CO2 and greenhouse gases, and as well, to avoid energy source wastage.