Renewable Sources Of Energy
The fact that fossil fuel reserves are decreasing and that the atmospheric pollution caused partly by the use of these fuels are a threat to continuing agricultural production in the current manner has brought the focus back to renewable sources of energy. Many techniques involving solar, wind or biogas energy have been developed in the agricultural field that are now applied in various regions of the world.
Solar energy
Technologies using direct solar energy to produce electricity, to provide heating, to cook and to distillate saline water are being studied and tried out in many countries. (put picture of solar panels in California) Most of them are not yet practicable or economical on a large scale.
Photovoltaic cells
Photovoltaic cells generate an electrical current when sunlight excites electrons in the cells. This electricity, produced from various sizes of photovoltaic units, can be used either in homes, industries or farms. Livestock farmers use this technology already in a limited capacity to electrify fences and pump water in remote locations. The use of these cells is expected to increase, but first improvements are needed to make them economically competitive. The major environmental hazards associated with photovoltaic cells is the use of toxic chemicals such as cadmium sulfide and gallium arsenide in their manufacture.
Agricultural or sewage waste can be collected and transformed to readily usable gas in on-farm plants (refer to proper place in non-food uses section).
Passive heating and cooling of buildings
Passive solar heating technologies "make use of the structural elements of a building to collect, store and distribute heat" (Pimentel, 1996). Natural cooling, on its side, include ventilation, attic radiant barriers, day-lighting, landscaping and wingwalls. The most effective solar systems include appropriate building insulation, solar water heaters, south facing windows, construction of a portion of the building underground, heat storage units and roof overhangs (Pimentel, 1996). Currently, solar heating is becoming more economical: a pilot scheme to heat water in dairy farms in New Zealand suggests that the cost is about the same as for electricity.
Wind energy
Wind power has been used since primitive times to provide energy for farming operations such as pumping water, running mills or other machines. Modern aerobic technology is now being applied to design highly efficient, cheap, and economical wind-powered electricity generators. However, the availability of sites with sufficient wind (at least 20 km/h) limits the widespread development of wind farms.
Biogas production
Saving Energy | Sources