**3. Decentralized energy-water-food systems**

Decentralized energy-water-food systems are the proposed solution for rural farmers in SSA to provide the necessary amount of electricity that fosters a higher level of human development. It addresses the low purchase power of the local community, gives renewable-based power access as pillar for human development, and increases the income of local community through agricultural productivity. It is based on the water-energy-food nexus, a conceptual framework for integrated resource management, which took particular prominence in 2011 as a wake-up call reacting to the forecast of a worldwide increasing resource demand, climate change, and the awareness of the unsustainable stress on scarce resources (energy, water, and food) [18]. As a result, it supports the coordination and management of the three sectors and the decision-making process under the consideration of synergies and trade-offs between the three resources when dealing with human development challenges [19]. This system thinking has from henceforth had an impact on the new policy frameworks, business assessment methods, and modeling tools, specially addressing challenges in the urban context and the multi-sectoral use of energy [20]. However, the application of this approach in the context of rural development of farming communities is limited. Due to the transformational effect of the nexus thinking [21], it deserves the formalization of a concept framework that is suited for rural farming communities and for sustainable economic development.

The model scheme for a decentralized energy-water-food system with their major inputs and outputs is depicted in **Figure 2**. Key system characteristics are: into biogas and later converted into electricity (4). As a by-product, the biogas digestion process produces fertilizer that is used for agricultural purposes.

*boundaries, technological components, and commodity flows are depicted. Modified from [6, 7].*

**3.1 Least-cost design of decentralized energy-water-food systems**

Decentralized EWFS have potential to deliver social, environmental, and economic returns. The sector coupling causes an unavoidable complexity in designing EWFS, specially when the lowest cost and technical feasibility are to be guaranteed. Optimization models facilitate the engineering effort to provide basic dimensions for the system implementation. These models are the state of the art for rural electrification as they enable stakeholders to understand, evaluate, and ultimately make decisions about the system setup [25, 26]. To date, there are only a limited number of models accessible to researchers that address all three resources of an EWF system together, and most tools cannot be customized to the specific environmental and economic characteristics of the respective project location [27]. The

energies.

**103**

**Figure 2.**

As a result, the rural community not only has gained access to electricity and domestic water supply but also secures the year-round supply of water for productive uses and food. In the medium to long term, the improved agriculture has the potential to create fair-paid jobs, increase the community's purchasing power, lead to a higher standard of living, and provide economic opportunities [12]. This concept also suggests that the high, so far unaffordable, investment costs for infrastructure development can be repaid by the local population through their revenues in agriculture as crops yield increase by up to 300% with regular irrigation [24]. After paying the system investment and operational costs, profits are distributed to the local community. Besides this socioeconomic benefits, preliminary studies of this concept in [6, 7] showed that due to the high resource potential of solar and biomass, the cheapest power generation is based to over 90% on renewable

*Business model scheme of decentralized energy-water-food systems. Major inputs and outputs as well as system*

*Economic Development of Rural Communities in Sub-Saharan Africa through Decentralized…*

*DOI: http://dx.doi.org/10.5772/intechopen.90424*

1.Hybrid power system


The combination of the photovoltaic battery and biogas system provides electricity to meet the private demands of a community. Because the deployment of diesel generators in off-grid villages is widespread [22], it is considered in this concept as well (1). Private power is provided free of charge in a first step and priced to cover potential system losses if needed. The hybrid power system generates enough power to operate electric groundwater pumps (2), powered mainly with cheap solar energy enabled by the strong global irradiation in SSA and by the flexible load management of water pumps. These pumps supply the community with domestic water demand. In this concept, up to 50 liters per day and capita are provided free of charge to meet the drinking and sanitation water right standards [23]. The pumps supply also all-year irrigation under the consideration of arable land and groundwater use constraints. Community farmers are able to grow crops independent of the rainfall pattern. This allows multiple harvests per year for selling to the domestic or external market participants (3). The resulting higher agricultural productivity leads also to an increase in biomass waste, which is fermented

### *Economic Development of Rural Communities in Sub-Saharan Africa through Decentralized… DOI: http://dx.doi.org/10.5772/intechopen.90424*

#### **Figure 2.**

development goals and opportunities to use energy access to stimulate economic activity" [9]. In the absence thereof, rural electrification may not bring the

Decentralized energy-water-food systems are the proposed solution for rural farmers in SSA to provide the necessary amount of electricity that fosters a higher level of human development. It addresses the low purchase power of the local community, gives renewable-based power access as pillar for human development, and increases the income of local community through agricultural productivity. It is based on the water-energy-food nexus, a conceptual framework for integrated resource management, which took particular prominence in 2011 as a wake-up call reacting to the forecast of a worldwide increasing resource demand, climate change, and the awareness of the unsustainable stress on scarce resources (energy, water, and food) [18]. As a result, it supports the coordination and management of the three sectors and the decision-making process under the consideration of synergies and trade-offs between the three resources when dealing with human development challenges [19]. This system thinking has from henceforth had an impact on the new policy frameworks, business assessment methods, and modeling tools, specially addressing challenges in the urban context and the multi-sectoral use of energy [20]. However, the application of this approach in the context of rural development of farming communities is limited. Due to the transformational effect of the nexus thinking [21], it deserves the formalization of a concept framework that is suited for rural farming communities and for sustainable economic

The model scheme for a decentralized energy-water-food system with their major inputs and outputs is depicted in **Figure 2**. Key system characteristics are:

The combination of the photovoltaic battery and biogas system provides electricity to meet the private demands of a community. Because the deployment of diesel generators in off-grid villages is widespread [22], it is considered in this concept as well (1). Private power is provided free of charge in a first step and priced to cover potential system losses if needed. The hybrid power system generates enough power to operate electric groundwater pumps (2), powered mainly with cheap solar energy enabled by the strong global irradiation in SSA and by the flexible load management of water pumps. These pumps supply the community with domestic water demand. In this concept, up to 50 liters per day and capita are provided free of charge to meet the drinking and sanitation water right standards [23]. The pumps supply also all-year irrigation under the consideration of arable land and groundwater use constraints. Community farmers are able to grow crops independent of the rainfall pattern. This allows multiple harvests per year for selling to the domestic or external market participants (3). The resulting higher agricultural productivity leads also to an increase in biomass waste, which is fermented

economic development it promises.

*Regional Development in Africa*

development.

**102**

1.Hybrid power system

2.Electric water pumps

3.Yield optimizing and sustainable agriculture

4.Biogas generation through agricultural waste

**3. Decentralized energy-water-food systems**

*Business model scheme of decentralized energy-water-food systems. Major inputs and outputs as well as system boundaries, technological components, and commodity flows are depicted. Modified from [6, 7].*

into biogas and later converted into electricity (4). As a by-product, the biogas digestion process produces fertilizer that is used for agricultural purposes.

As a result, the rural community not only has gained access to electricity and domestic water supply but also secures the year-round supply of water for productive uses and food. In the medium to long term, the improved agriculture has the potential to create fair-paid jobs, increase the community's purchasing power, lead to a higher standard of living, and provide economic opportunities [12]. This concept also suggests that the high, so far unaffordable, investment costs for infrastructure development can be repaid by the local population through their revenues in agriculture as crops yield increase by up to 300% with regular irrigation [24]. After paying the system investment and operational costs, profits are distributed to the local community. Besides this socioeconomic benefits, preliminary studies of this concept in [6, 7] showed that due to the high resource potential of solar and biomass, the cheapest power generation is based to over 90% on renewable energies.

#### **3.1 Least-cost design of decentralized energy-water-food systems**

Decentralized EWFS have potential to deliver social, environmental, and economic returns. The sector coupling causes an unavoidable complexity in designing EWFS, specially when the lowest cost and technical feasibility are to be guaranteed. Optimization models facilitate the engineering effort to provide basic dimensions for the system implementation. These models are the state of the art for rural electrification as they enable stakeholders to understand, evaluate, and ultimately make decisions about the system setup [25, 26]. To date, there are only a limited number of models accessible to researchers that address all three resources of an EWF system together, and most tools cannot be customized to the specific environmental and economic characteristics of the respective project location [27]. The

water infrastructure, or telecommunications network. Although agriculture is their main economic activity and livelihood, farming in Kpori is 100% rainfall dependent. At the same time, domestic water supply relies on rainwater harvesting and hand pumps. As a result of a significant drop in rainfall and an increase in temperature over the last century, the already climatically stressed region is dependent on drought-resistant plants such as maize and sorghum. According to on-ground questionnaire, Kpori's inhabitants have an annual income per capita below the lower

*Economic Development of Rural Communities in Sub-Saharan Africa through Decentralized…*

As depicted in **Figure 3**, *urbs* already includes the EWFS model and optimization

• Technical parameters: Efficiency, capacity, and lifetime of machinery and

• Economic parameters: Weighted average cost of capital (WACC), investment cost, fixed cost, variable cost, purchase cost, and fuel cost of machinery and

The community demand for residential electricity and domestic water is determined by the approx. 300 Kpori inhabitants distributed over 70 households with an average household size of 4.4 [32]. The hourly private power demand is obtained by a Monte Carlo simulation based on the hourly utilization probability of residential appliances and their rated power. This data was obtained from an on-site survey on the nearest electrified farming community. The results of **Figure 4** show a typical load profile of a farming community with a total annual consumption of 42.5 MWh

Domestic water demand is set to 50 liters per day and person based on the drinking and sanitation water right standards [23]. Daily food demand is modeled as 658 g of maize grain per inhabitant, which covers the minimum dietary calorie intake of 2400 kcal [33]. In Kpori, up to 263 tons of maize grain can be produced annually on the domestic farmland due to the maximum capacity of arable land of

*Time series electricity demand for a Kpori house obtained with Monte Carlo simulation.*

script. The input data needed about Kpori are the following:

• Supply time series: Solar irradiation, rainfall

• Demand time series: Residential electricity, domestic water, food

poverty line of 208 USD/year [31].

*DOI: http://dx.doi.org/10.5772/intechopen.90424*

**4.1 Model input**

storage units

storage units

or 138 kWh per inhabitant.

**Figure 4.**

**105**

#### **Figure 3.**

*Work flow to obtain least-cost design of decentralized energy-water-food systems with programming tool urbs. A business analysis is derived from the output results.*

contribution [6, 7] addressed the adaption of *urbs*, an economic model, which was originally designed by the Chair of Renewable and Sustainable Energy Systems of the Technical University of Munich (ENS) for distributed energy systems. *Urbs* has a well-documented mathematical description; it is open-source and can be used for cross-sectoral models in any spatial and temporal resolution [28]. Hence, it is used to conduct the economic feasibility analysis aimed in this work.

*urbs* is a linear optimization tool programmed in Python and identifies the optimal system configuration based on the minimization of the total system costs resulting from the techno-economic modeling of each process and storage technologies in the system. **Figure 3** gives an overview of the *urbs* model for decentralized EWFS.

It requires three kinds of input data. Site data is defined by the demand, solar and rainfall time series, techno-economic parameters of the processes and storages as depicted in the EWFS model schema (**Figure 2**), and lastly the market prices of the commodities that can be bought or sold between the system boundaries. This data is read by *urbs*, which already has an implemented script adapted to model EWFS with a linear approach [7], and the total system costs are optimized. The output data includes the installed capacities related to the three sectors, the commodity flows, total revenues, and costs. A pre-feasibility analysis can be conducted on the basis of these results to evaluate the business attractiveness and ensure a sustainable project operation.
