Renewable Energy Technologies for rural areas
Due to their geographical location and the lack of critical mass, rural areas are mainly suitable for renewable energy off grid applications, systems which are connected to a battery via a charge controller, which stores the electricity generated and acts as the main power supply.
Rural electrification often demands decentralized solutions, namely isolated systems covering basic electricity needs or mini grids which are larger systems providing electricity to several households. Renewable energies based mini grids are less dependent on larger-scale infrastructure and could be placed in service faster, especially in rural areas.
Renewable energy technologies avoid greenhouse emissions, have low operation and maintenance costs, generate employment and allow decentralized production for the development of dispersed populations. Within rural areas, they are capable of electrify homes, villages, farms and small industries as well as being used for telecommunications, water supply and irrigation
The use of these technologies in rural areas reduce the need for candles, kerosene and battery charging and improves indoor air quality and higher quality of lamps than kerosene for reading (electric lighting is up to 200 brighter than kerosene lamps).
| TECHNOLOGY | EXPERIENCE WORLDWIDE | COMMERCIAL STATUS |
| Photovoltaics | Extensive | Fully commercial |
| Wind mechanical water pumps | Extensive | New commercial designs offer increased reliability and improved performance |
| Small wind electric | Extensive | Commercial and evolving rapidly |
| PV/diesel hybrids | Extensive, especially for telecommunications worldwide | Fully commercial and the preferred option for remote telecommunications, commercially evolving for village power |
| Wind/diesel hybrids | Significant, not yet extensive | Commercial, competitive, and evolving |
| Small modular biopower units (10 kWe to 100+ kWe) | Some | Under development, first commercial products becoming available |
| Small packaged biopower units (100 - 500 kWe) | Some | Limited but expanding commercial availability; expanded commercialization underway |
| Bioenergy > 0.5 Mwe | Extensive, in wood and agro industries worldwide | Commercial site-engineered systems |
| Microhydro electric | Enormous (e.g., China, Nepal, Vietnam) | Fully commercial, with innovative products emerging |
Choosing the most appropriate technology option for rural areas
The way to determine the most appropriate technological solution implies always a feasibility study based on gathering field data for each specific site. Technical, economic, financial, and socio-cultural considerations must all be including in the decision process to ensure the appropriate choice of technologies. The following basic criteria should be considered to design an optimal power solution:
Location: The suitability of the site to be electrified, in terms of the topographic and geographical characteristics, will be the first criteria to look at when deciding on the implementation of the most appropriate technology
For example, when planning to build up a small hydropower plant, a site with the largest fall and the shortest distance to the power house should be chosen.
Wind turbines should not be installed near buildings, trees and other obstacles to avoid turbulence and loss of energy production. Wind turbines should be 2m above any building or obstacles in the area. The site for the turbine should be as near as possible to the control room to reduce line losses
Resource evaluation: Resource evaluation includes the collection of data and interpretation of this data.
Solar
The solar resource is linked to solar irradiation, latitude, altitude, cloud cover and content of water vapor and dust in the air. Therefore, the essential factors to take into account in solar energy application are the monthly average of daily sunshine hours, site latitude, local average cloudy days, foggy days, rainfall days etc
Wind
The power in the wind is directly related to the cube of the wind speed and to the air density, wind resources become exploitable where average annual wind speeds exceed 4-5 m/s. Essential factors for wind resource evaluation are the monthly average wind speed; height at which wind speeds were measured; site altitude; daily variations in wind speed, the diurnal wind pattern; frequency distribution of wind speed; primary seasonal wind directions; topography of the site; forestry cover at sight, height of the tallest growth
SHP
Flow rate (liters/s) and net head (m) of water determine the energy output of a hydropower system. Therefore, the essential factors for SHP resource evaluation: annual flow rate; monthly distribution of the resource
Load analysis: A load analysis should cover:
- Load type. There are three main groups to be considered: domestic loads (lighting, TV, refrigerator, iron, etc), community loads (schools and public lighting and appliances, water pumping, etc) and commercial loads (electric power tools, etc);
- Load calculation or how much power is required;
- Load growth. The scale of the system will be determined in terms of load to be served, therefore a study of current and future demand for electricity on site is critical to avoid power shortage. Further, the adoption of flexible system design that can be expanded as load demand increases can mitigate risks associated with unpredictable load growth rates
Rated Power and average daily working hours for typical loads
| Load / Application | Rated Power (W) | Average daily working hours (h) |
| Energy saving lights | 9-30 | 5 |
| 21” Color TV | 70 | 5 |
| B/W TV | 20 | 5 |
| Cassette recorder | 40 | 2 |
| Washing machine | 150 | 2 |
| Refrigerator | 120 | 10 |
| 1/5 HP Water Pump | 165 | 0,5 |
| Radio set | 10 | 1 |
| Dust cleaner | 750 | 1 |
| 2 Pair conditioner | 2000 | 5 (Jun-Sept) |
| Electric fan | 50 | 2 (Jun-Sept) |
| Moveable Electric Heater | 1000 | 3 |
| Bubble Jet Printer | 20 | 1 |
| Desk computer | 400 | 5 |
| Monitor | 200 | 5 |
| Fax machine | 100 | 30min |
| Microwave stove | 1000 | 10min |
Source: China Village Power Project Development Guidebook