Hydro, solar, wind, biomass and human are classified as renewable energy sources. These sources are inexhaustible and infinite. Extraction of these sources does not have environmental implications. These sources are used by human since time memorable. Simple and modern technological changes increase efficiency and capacity of these sources. Few of these technological changes are listed below.

Improved Cooking Stove

This produce no smoke or less smoke during cooking and preserve more heat than ordinary traditional cooking stove. The cost of installation is very less and can be produced locally. Impact of this stove is positive on health of family members, especially women and also consumes less fuel wood for cooking.

Biogas

Cow and other livestock’s dung and also human excreta are used to produce gases. The produced gas is used for cooking. Residual is used as high quality organic fertilizer. The cost of installation of one biogas plant ranges from NRs.16,000 to NRs.35,000 depending upon the size of the plant and its location.

Subsidy amount ranging from NRs.7,000 to NRs.12,000 is provided to farmers by the government depending upon the remoteness geographic location and size of the plant.

Gasifier

Wood, fuel wood, dried cow dung and other organic elements are put in a big tank and combusted in low air pressure. Smoke formed is cooled and small solid particles are removed. Filtered cooled smoke is used to run engine. Another benefit of using gasifier is household waste is disposed cleanly. Precautions need to be taken while combusting and disposing coal.

Improved Water Mill

To increase generation capacity of traditional water mill iron fan is added in an improved water mill. In improved water mill, generator is installed to generate electricity. Cost of installation of an improved water mill is about NRs.27,000. Additional NRs. 55,000 is required to add generator for producing 1.5kW of hydroelectricity.

Micro Hydropower scheme

Electricity up to 100 kW is generated by micro hydropower scheme. Water is diverted from a river and flown through a canal upto forebay. From forebay stored water is then run down to the turbine (fan). The fallen water with high velocity rotates the turbine and generates Mechanical Power. This Mechanical Power is used to run generator to generate electricity. Energy produced is use for grinding and crushing of grains. Electricity is generated by using generator. The cost of generation of per kilowatt electricity ranges from NRs.1.5 lakh to NRs.2.0 lakh. Subsidy amount of NRs. 70,000 is provided to communities per kW of power output by the government.

Solar Box Stove

Solar radiation is reflected and preserved in a box structure. The box is designed in such a way that black pointed cooking utensil is put inside the box. Black color absorbs more solar radiation heance faster cooking. It costs about NRs.1,000 to produce one box.

Solar Water Heater

Black colored collector and pipe absorb solar radiation and warm water flowing inside. Warm water raises up and pours into water tank. Cold water from the bottom of the tank run into the collector and pipe. The cost of installation of ordinary solar water home heater is approximately NRs.15,000.

Solar Drier

It uses solar radiation to dry grains, fruits and green leafy vegetables. Box structure with one inlet at the bottom and another at the top is prepared. Grains, fruits and vegetables to dry are put inside the box and box is put in the open place under the Sun. The cost of preparing solar drier is about NRs.2,500.

Solar Electricity

Solar energy is converted into electricity by use of photovoltaic cell. Generated electricity is preserved in a battery and use whenever necessary or used immediately after generation. The cost per kW of electricity generated ranges from NRs.17,000 to NRs.45,000 depending upon the capacity. This technology is especially applicable in remote places where generation of micro hydroelectricity is not feasible.

Wind Energy

This is applicable is places where wind flow continuously in greater speed. Strong wind rotates wings of a mill. Generator attached in the mill also rotates with the wings of the mill producing electricity. Electricity is used immediately or stored in battery. It is also used to pump water for irrigation to farmland. Cost of constructing and operating wind mill to generate one kW electricity is approximately NRs.1,50,000 and additional NRs.70,000 is estimated for constructing water pump.