Zukünftige Energie- und Industriesysteme
Techno-economic feasibility study of solar and wind based irrigation systems in Northern Colombia
(2014)
Water pumping systems powered by solar and wind energy are a clean, decentralized and economic alternative for the irrigation of crops. The intense droughts experienced in the last years in Northern Colombia due to particularly strong Nino Phenomena have reactivated the need of reliable water pumping irrigation systems in that region. This study aims to assess the techno economic feasibility of solar and wind based pumping irrigation system, taking as case study the Municipality of Piojo in the Atlantico department. In the first stage of the study the irrigation water requirements were determined by using the software CROPWAT based on two different crop patterns that represent existing feasible alternatives for small farmers of the region: i) a common crop pattern, which represent the current average distribution of crops for subsistence farming and ii) a fruit cash crop pattern that comprises crops for which well established markets in the region exist. Solar wind and diesel based pumping systems were sized based on the crop water demands for 1 ha. The unit irrigation costs of the three technologies, the two crop patterns and the three irrigation methods (surface, sprinkler and drip) were calculated and compared. The economical analysis was complemented with a cost-benefit analysis over 20 years. Our results show that both renewable energy based pumping systems (wind and solar) can cover the irrigation water demands of small farmers in the region. The economical analysis shows that windmills are the most cost effective solution followed by the solar pumping system. Diesel pumping system was the less cost effective, even though it does not comprise investment in water storage tank. The cost benefit analysis demonstrates that any irrigation system is financially unfeasible when providing water to a common crop pattern. In case of the fruit cash crop scenario the highest dividends were obtained by the wind pumping system and the lowest dividends by the diesel pumping system. The lowest payback period was obtained by the windmill after 7 years and could be even feasible after the fifth year if the surplus water would be used to irrigate larger areas. Dividends obtained in a fruit cash crop scenario with irrigation after 20 years were in the range of EUR 5200 and EUR 11200 higher than dividends obtained by the same crop pattern but without irrigation.
In many developing countries large parts of the population are negatively affected by the lack of access to clean and affordable energy. Providing sustainable energy services to these people has been acknowledged as a key component to reduce poverty. One form of development assistance to address the needs of the energy-poor at the local level are small-scale renewable energy projects. Like all development interventions, these energy projects are not intended to produce short-term outputs, but to create long-term impacts. Thus, it has become increasingly important to evaluate and accurately assess their sustainability. But despite the widely recognized need to identify successes factors and explain failure only few studies exist that address the sustainability of small-scale of energy development efforts post implementation. Against this background the paper presents the results of a post-evaluation of 23 projects supported via the Sustainable Energy Project Support (SEPS) scheme of the WISIONS initiative run by the Wuppertal Institute. The analysis provides insights on the influence that socio-economic, environmental, geographic and gender factors can have on the sustainability of small-scale renewable energy projects in developing countries.
Access to sustainable and affordable energy services is a crucial factor in reducing poverty in developing countries. In particular, small-scale and community-based renewable energy projects are recognized as important forms of development assistance for reaching the energy poor. However, to date only a few empirical evaluations exist which analyze and compare the impact of these projects on local living conditions and their sustainability ex-post implementation.
To better understand the impacts and the conditions that influence sustainability of these projects, the research presented in this paper evaluated 23 local development projects post implementation. By applying an standardized evaluation design to a cross-sectional sample in terms of renewable energy sources (solar, wind, biomass, hydro), user needs (electricity, food preparation, lighting, productive uses), community management models, finance mechanisms and geographical locations, the review results provide valuable insights on the underlying conditions that influence the success or failure of these small-scale local energy interventions. The empirical evidence suggests that the sustainability of small-scale energy implementations (≤100 kW) in developing countries is determined by the same factors, independent of the socio-cultural, political and ecological context. These findings allow to better predict the long-term success of small sustainable energy projects in developing countries, this can help to improve project designs and increase the certainty for future investment decisions.