The facts about clean energy Clean energy is renewable energy having minimal impact on or without any pollution to environment of our earth. Clean energy utilizes natural resources which are renewable, such as wind, water, sunlight, geothermal, tides, biomass and so on, all these natural resources are abundant and can be replenished in a short of period. Clean energy will not contaminate our environment after consumption of them. The power generated by clean energy is also called green power. Clean energy technologies range mainly from solar power, hydropower, wind power, which bring human being green power, reduce the greenhouse gas emission effectively and make significant contribution against the global warming. Hydro Power The hydro power projects will be various depending on the following characteristics: 1. Maximum water head, Minimum water head and Design water head; 2. Maximum flow/discharge, Minimum flow / discharge and Design flow /discharge; 3. Setting elevation of turbine-generator unit and tail water level; 4. Characteristics of water supply system, such as power tunnel, diversion channel and penstock etc; 5. Water conditions, ambient temperature and humidity; 6. Layout of turbine-generator units in powerhouse; 7. Any restriction to transport size and weight of equipment; 8. Scope of works or supply required for the projects. Solar Power Solar power is playing an important role in renewable energy consumption. Solar power system is featured with energy saving, environmental protection and one-off investment for long term benefit, and it has been applied to generate green power for private houses, commercial or public buildings. The in-grid solar power systems are cheaper than off-grid systems because of no any requirement for battery banks and chargers / controllers. The array of PV panels as a main part of in-grid solar power system produces electricity during the day and feed any no consumed electricity back to the local electricity grid via a bi-directional inverter. At night the house is powered from the grid in the normal way. If production of your solar power system is higher than consumption during the day and at night from the grid, there may be net export of electricity from your system to the grid. Besides the net export to the grid, the price of electricity fed to the grid from your solar power system is different from the one you get from the grid. In many countries around the world the electricity price fed back to the grid is higher than the retail electricity price of the grid. This will reduce your electricity bills in coming years, which will help offset the cost of supply and installation of the system whilst you take this way to prevent the climate change. The off-grid solar power systems consist of PV panel array, battery bank, inverter and controller, it can be independent from the local electricity grid and generally used in remote sites without local electricity grid. The power of output from the system will be depending on your requirement.