Elsevier

Applied Energy

Volume 91, Issue 1, March 2012, Pages 130-145
Applied Energy

Design of decentralized energy systems for rural electrification in developing countries considering regional disparity

https://doi.org/10.1016/j.apenergy.2011.09.022Get rights and content

Abstract

Decentralized electrification using local resources can reduce regional disparity in rural and remote areas in terms of supply reliability and cost, as well as promote income generation. In this research an optimization energy model is introduced for designing decentralized energy systems using biomass for rural electrification in developing countries. Regional disparity is incorporated disaggregating electricity demand into urban, rural and remote areas. The model has been applied for designing a decentralized system using agricultural waste and forest biomass in a region in Colombia, South America. The resulting design includes biomass technologies in remote areas, reducing supply cost by 30% in this region. Using agricultural waste for electricity generation increases unit costs by 25% and reduces 15% of CO2 emissions compared to the current energy system. Using all biomass to meet current demand lowers the efficiency of the system, resulting in high system costs and emissions reduction. Reduction of disparity in electricity access among regions using local biomass needs to balance the increase in energy system costs and CO2 emissions reduction. For instance, using 30% of available biomass reduces 22% of system CO2 emissions, and provides 121 USD/house/yr and 99 USD/house/yr of additional income in rural and remote areas, respectively. Design of the energy system considering regional disparity shows that fuel transportation costs and efficiencies of biomass conversion technologies have significant impact on system configuration and performance.

Highlights

► Model for designing decentralized energy system with regional disparity. ► Biomass-based electrification promotes access and income in remote and rural areas. ► Costs and income generated balance using 30% of available biomass in target area. ► Efficiency and cost of technologies, and fuel transport cost are important factors. ► Promote biomass-based system internalizing emissions reductions and income benefits.

Introduction

Better access to modern energy sources such as LPG and electricity is a necessary condition for improving living conditions and reducing poverty in rural areas of developing countries. Currently over 1.3 billion people living in rural areas have no access to electricity. They represent 80% of the world population without the service [1]. In countries with a large share of urban population and a small participation of the agricultural sector in the national economy electrification needs focus on the reduction of disparity between rural and urban areas. Access and quality of energy supply, as well as the consumption patterns of households present considerable differences between these regions. A graphic representation of regional disparity in energy supply in developing countries is showed in Fig. 1. In urbanized countries rates of electrification in urban areas are close to 100%, different to countries where access to electricity is small in both urban and rural areas. On the other hand, electrification rates in rural areas are disproportionately low. Even when electricity supply is available, the service is unreliable and expensive. For example, electricity supply is limited to a few hours a day, with high losses in transmission and distribution, frequent blackouts and power fluctuations. Moreover, electrification of remote areas is largely unachieved in these countries due to the deficient transportation infrastructure [2], [3].

An alternative for electrification of rural and remote areas is the introduction of decentralized conversion technologies using resources locally available. Decentralized electrification can provide a more reliable supply and generate income derived from the use of local resources [3], [4]. For example, the use of agricultural and forest wastes, as well as other biomass resources in combustion technologies for electricity generation decreases the dependence on foreign fuels and can provide income to local communities derived from biomass collection and transportation.

In addition to increasing access to electricity, the design of decentralized energy systems for rural electrification in developing countries must consider regional disparity. The large differences between urban, rural and remote areas can be interpreted beyond the geographical location including income disparity. Disaggregating the demand side of the energy system into different regions helps to describe the income opportunities according to the availability of biomass energy resources. Incorporating income differences allows the characterization of the energy system’s performance based on the impact of electricity costs on energy expenditure in households with different incomes. Several energy models analyze the use of biomass in rural areas of developing countries applying optimization methodologies [5], [6]. However, few applications consider regional differences and the income generated by using biomass energy resources.

In this research a linear programming (LP) model has been developed in order to design decentralized energy systems for rural electrification using local biomass resources, considering disparity in energy consumption between urban and rural areas. A third region, referred to as remote areas, and which describes areas located outside the service area of the electricity grid, has been introduced. The performance of the system is evaluated based on the financial viability from the perspective of electricity producers, the local income and energy expenditures in households, and the mitigation of CO2 emissions. The energy system analyzed considers the use of agricultural wastes and forest wastes for electricity generation by means of several energy conversion technologies using biomass (direct combustion of biomass in boilers and gas turbines coupled with gasification unit). The target area is a region in Colombia, South America, characterized by abundant biomass resources in the form of agricultural wastes, with partial coverage of the electricity grid, where over 15% of population has no access to electricity. Currently, electricity from the grid covers the interconnected area, and diesel generators using diesel fuel supply the non-interconnected area.

Section snippets

Promotion of rural development with biomass based electrification

Access to electricity is an important component of rural development. Better access to electricity has been correlated to the improvement of living conditions in several aspects, such as education and income generation [7]. Electrification in rural areas of developing countries, and in particular in the case of remote areas, is difficult due to low population densities, highly dispersed location of populated centers, low energy consumption levels per capita and poor road infrastructure which

Decentralized energy system for rural electrification

In this study, an optimization model has been developed and applied for designing energy systems for decentralized electricity supply considering conversion technologies using biomass. The model incorporates regional disparity disaggregating the target area into urban, rural and remote areas. Urban areas correspond to large cities. Rural and remote areas are differentiated according to their location within or outside the areas where interconnection to the electricity grid is available. Both

Target area

The target area is a department in Colombia called Meta, corresponding to one of the 32 administrative divisions of the country. This region is a suitable case for analyzing the potential of decentralized electrification to narrow disparity between rural and urban areas in developing countries. Compared to other departments of Colombia, Meta has a considerable area outside the interconnected system in spite of its proximity to the capital city of the country, as showed in Fig. 5.

This region is

Optimal energy system design

The application of the LP model provided the optimal design of the energy system for the scenarios considered. In the design for the Least-cost scenario, shown in Fig. 7, biomass is used only in remote areas, where conversion plants based on biomass gasification are used to supply electricity instead of diesel generators using diesel fuel. Sugarcane waste and planted forest waste contribute in this region to 40% and 60% of the resource supply, respectively. In rural areas that currently lack

Discussion

The design of the energy system considering decentralized electrification with local biomass resources provides a more suitable alternative for electricity supply in remote areas based on the minimization of system net costs. Long distances prevent the deployment of diesel generators using diesel fuel and extension of the electricity grid. On the other hand, using local biomass resources reduces the dependence on foreign resources and the cost of electricity supply, thus, rising the reliability

Conclusion

The introduction of regional disparity in the design of decentralized energy systems for rural electrification shows that transportation distances and conversion efficiencies of biomass technologies are essential factors for shifting from foreign fuels to local biomass to promote rural development. Biomass use for electrification reduces disparity in remote areas. Electricity costs reduce and net local income increase, resulting in improved access to electricity according to the lower income

Acknowledgements

The authors are grateful to the reviewers for their valuable comments on the contents of this paper.

Diego Silva Herran is grateful to the Japanese Ministry of Education, Culture, Sports, Science and Technology for the financial support provided through its scholarship program.

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