# Technologies for Rural Development/Creating energy

Energy is used for many purposes, as a culture becomes more complex the uses for energy diversify.

## Basic energy uses

The prime need for energy use in all parts of the world is for food preparation, preservation in hot climes & cooking. In cold climates it is essential for heating living spaces.

## Energy Sources

* Firewood
* Solar energy
** Solar Energy for cooking
** Solar energy for water heating
** Solar energy for creating electricity
* Hydroelectricity
* Hydromechanical
* Wind energy
* Connection to the network

### Firewood

Firewood is the oldest and often most accessible energy source. An open wood fire can be used to cook food. There are many types of stoves and ovens that use wood to create heat for cooking and for heating of living spaces.
It is important to consider the source of the firewood; in many areas in the world people have cut all the trees down in an area to supply firewood or building material leaving no trees for future generations. As a general rule for every tree that is cut down 3 new ones should planted.

### Solar Energy

The energy from the sun can be used to heat water or even cook food; this is the best way to do this from an environmental point of view. It creates no pollution and uses no resources apart from those used for its fabrication.

#### Solar Cooking

Solar cooking has been used for centuries by explorers travelling in areas without access to wood to create fire. Since the 1970´s general interest has increased because of the energy it saves.
The simplest design is called the CooKit designed by Frenchman Roger Bernard en the early 1990´s; it is made from cardboard tinfoil a heat resistant plastic bag and a dark coloured pot.
See links below for more information.

#### Solar for Heating Water

Solar water heating systems are very efficient. In developed countries where it is common to heat water with electricity or gas from a centralized system, the cost of the installation can be paid back from saving in energy costs.
For rural development simple solar heating systems can be used to heat water even in areas the electricity or gas network has not yet reached.
Solar heating of the water is also called solar pasteurization; by heating the water many viruses and bacteria that cause diseases are killed. Hot water can also be used to clean living spaces and cooking and eating utensils more effectively.

#### Solar for Generating Electricity

Using solar energy for creating electricity is an environmentally friendly process but is unfortunately not very efficient, primarily because of the cost of fabrication of the solar panels. It is a very good technology when small amounts of energy are needed; to supply power for school computers etc.
If electricity is needed at night then a battery system must be added to store the energy.

### Hydroelectricity

If there are waterways nearby, dams are a very easy way to create energy in mechanical form; this can be turned into electricity with a turbine and generator.
The main problem with damming waterways to create energy is the change in ecosystem it creates, and the negative effect is has on the movement of silt downstream, the probability of the dam silting up, & the migration of fish up and downstream.
It is very important to create fish passes (ladders) so that the natural migration of fish can continue.
Small scale hydroelectric sets can be placed directly in streams with little or no civil engineering needed other than to anchor the set.

### Hydromechanical

This is a very old technology, & is simply extracting energy as torque, via a paddle-wheel of some sort, & applying it to a set of grinding wheels, hammers

### Wind Energy

Wind energy was first harnessed in Persia around 200BC to grind grain, shortly after the technology was copied by the Romans and consequently spreads across Europe where it has been used for pumping water and grinding grain until the early 20th century.
The first wind-,turbine used to create electricity was constructed in the United States in 1888, since then they have been used for pumping water or generating electricity in isolated areas around the world primarily on farms.
Wind turbines range in size from small 30 cm diameter models used to generate small amounts of electricity, to 10m high 2m diameter wind-turbine that typically has many blades, to giant 100m high 120m diameter wind-turbine that produce up to 5MW of energy.
In rural areas where it is not possible to connect to the electrical network, wind-turbines can installed to pump water and generate electricity.

## Energy Storage

Electrical energy can be stored mechanically or chemically. The most common mechanical storage is by damming water; this can be done by waiting for it to flow into a dam or by pumping it up into a dam using excess electricity in a network. Batteries use a chemical process to store electricity. This process is not very efficient, batteries are expensive to make & dispose of, and even rechargeable ones have quite short life spans. Therefore it is best to try and avoid storing electricity and only create it when it is needed. That is why developed countries have large electrical networks to supply the electricity as it is generated.

## Connecting to the Electrical Network

The first electrical network was connected in New York in 1883 by Thomas Edison the American inventor at the worlds first Research & Development centre. Since then the network has grown across the globe with most most developed countries in the world having centralized networks by mid 20th century.
Because alternative energy sources are only available when there is wind or sunshine, having a village connected to the electrical network means that excess energy produced from generation installations can be sold and when there is no wind or sunshine needed energy can be purchased. This is more efficient and environmentally friendly than using batteries.

## Environmental Considerations

Energy creating generally uses up resources, which should be replaced if possible; trees cut down for firewood should be replaced with 3 trees planted.
Energy creating also produces Carbon Dioxide and other gases which pollute the air. CO2 (Carbon Dioxide) is one of the known Greenhouse gases, which may be linked to Global warming.
Whenever possible it is best to use renewable energy sources like solar or wind energy, and also try and be inventive about the way of using energy to minimize the amount that is used.

## Further Reading

* PDF file with comprehensive information about Solar Cooking.
* Solar Cookers International
* Climate Change/Renewable energy