**7.1 Design models with microgrids**

To study the possible use of microgrids in future projects, the electrification options with microgrids in Turco and Challapata are analysed. Although in both communities most households are scattered, there are small groups of households close to each other that could have been electrified with a microgrid.

To optimize the design of these alternatives a Mixed Integer Linear Programming (PLEM) model (Ferrer-Martí et al., 2011) is used. This model is based on the definition of a set of parameters (which specify the input data of the problem), variables (which define the configuration of the solution) objective function (which defines the standard resolution) and constraints (that specify the set of conditions to be satisfied that the solution is feasible). The solution of this model determines the point of generation and micro design to minimize costs, taking into account the demand, the wind resource and power generation equipment available in the area (cost and technical characteristics).

Next, the parameters, variables, objective function and constraints of this model are briefly introduced.

	- Demand: Energy and power consumption of each point and days of autonomy.

Due to the characteristic dispersion of communities, rural electrification projects tend to install individual systems at each point of consumption, as the cases presented in this paper. Alternatively, design of a single point of generation and distribution of electricity with

 Flexibility in use: energy generation and storage is shared among several users, thus one or more users can increase their consumption at a specific moment if needed. Easier integration of future users: new users may be electrified just extending a wire. Robustness against failure: microgrids facilitate feeding users with more than one generator. Thus, in case of failure of a generator, energy supply decreases but no user is

Cost savings: microgrids facilitate to use more powerful equipment, which are

In particular, the electrification with microgrids in Turco and Challapata would have

1. Some users were expecting to have more energy availability. The use of microgrid generation facilitates the use of more powerful and proportionally cheaper turbines, so more energy can be generated and supplied with the same investment. Moreover,

2. People that do not live permanently in the community were not electrified to avoid operation and maintenance problems. In systems with microgrids generation equipment is not installed at each household and, therefore, not living permanently is not a problem because the maintenance is common and not necessarily the

3. The lack of supply during breakdowns. In case of breakdown of a generator, no user is completely left without access, so the time taken to repair the system is not that

To study the possible use of microgrids in future projects, the electrification options with microgrids in Turco and Challapata are analysed. Although in both communities most households are scattered, there are small groups of households close to each other that could

To optimize the design of these alternatives a Mixed Integer Linear Programming (PLEM) model (Ferrer-Martí et al., 2011) is used. This model is based on the definition of a set of parameters (which specify the input data of the problem), variables (which define the configuration of the solution) objective function (which defines the standard resolution) and constraints (that specify the set of conditions to be satisfied that the solution is feasible). The solution of this model determines the point of generation and micro design to minimize costs, taking into account the demand, the wind resource and power generation equipment

Next, the parameters, variables, objective function and constraints of this model are briefly

Demand: Energy and power consumption of each point and days of autonomy.

higher energy supply scenarios can be considered with lower cost increase.

**7. Analysis of alternative designs** 

completely left without access.

proportionally cheaper.

responsibility of each user.

**7.1 Design models with microgrids** 

have been electrified with a microgrid.

available in the area (cost and technical characteristics).

critic.

introduced. Parameters

microgrids (Kirubi et al. 2009) has its advantages:

avoided some of the problems identified in the assessment:

	- Generation and accumulation: Energy and power balances at each point, required energy capacity in the batteries at each point of generation.
	- Definition of the microgrid: It establishes the relationship between energy and power flows and the existence of a conductor between two points, compliance of maximum voltage drop and maximum intensity, the structure of microgrid (if any) should be radial.
	- Equipment. Inverters are installed at the points of generation; the meters are installed at points of microgrid.

To specifically assess all the advantages of the microgrids, a constraint that forces to form microgrids to feed the households that were close to each other at each community is included.
