• Raj Chetty

• Chief Technologist

• Eskom Research, Testing and Development

• South Africa

Smart Microgrids for rural

electrification in South Africa

Introduction

• Problem statement: Approximately 3.3m South

African households do not have access to

electricity

• These are mainly deep rural communities

• Extending the grid to these communities is proving

to be costly

• 3.3m households at 200-500W ADMD per

household would also require an additional 660-

1650MW of capacity from the grid

Current electrification

Electrification plan

• Electrification program commenced in 1990’s

• Regarded as one of the more successful

programs undertaken

• Due to policies, initial focus was mainly on

urban households

• Currently 120k households per year are done

• Grid extension estimated at R200 000/km

• Focus shifted to rural areas in 2002

Issues with electrifying deep

rural areas

• Hard terrain makes grid extension more

costlier

• Communities usually sparsely located

• Roads can be inaccessible

• Far from utility Technical Service Centers

Deep rural sites

Solutions to providing universal

access

• Grid electrification – costly for deep rural communities, difficult terrain and sparse communities. Would require additional capacity.

• Solar home systems (SHS) – suited for sparsely distributed homes but provides limited supply and is not readily upgradeable to meet growth in demand and changing lifestyles.

• Off grid solutions using distributed sources (PV, wind) and energy storage that uses intelligent control and is modularly expandable to meet growth in demand. This approach is proving more feasible as costs of PV and storage technologies decrease.

International research

Typical Microgrid configuration

Simulation study

In order to provide a basis to further assess and study off grid solutions, a simulation study was done based on the following:

• A sample off grid, non-electrified community was chosen for the study

• The load per household was estimated using an estimation method

• The resource data was collected for the area

• The data was used as inputs in the HOMER modelling tool

Sample community

• Rural site

• 20-40 homes community size, located close to each other

• LSM 1-2 indigent community qualifying for Free Basic Electricity (FBE)

• Not connected to grid/distance from the grid in excess of 10km

Load estimation

• The PET (Pre-Electrification Tool) was used to estimate the load profile for the sample community based on:

• Herman-Beta method for estimation of load

• Income for households

• Geographic location

• LSM grouping

• The ADMD (After Diversity Maximum Demand) was estimated at 0.39kVA per household in year 1 increasing to 0.43kVA in year 15

• Estimated at average of 148kWh/day for a community of 34 homes, 0.39kW peak and 0.2kW average per house

Load estimation (primary input 1)

Resource data

• Following the load profile estimation, the renewable resources available at the location was determined.

• Data was obtained from the closest weather station and included:

– Solar irradiation

– Temperature

– Wind speeds

Resource data (input 2)

Simulation results

• Based on the estimated load profile data and renewable resource data for the sample community, the following was obtained using the HOMER simulation tool:

– 55kW of PV (Photovoltaic) from distributed generation to is needed to supply primary power to the load

– 5000kWh of battery storage is required

– LCOE (Levelised Cost of Energy) will then be $ 0.196/kWh taking into account the operate and maintenance costs and equipment during the project lifecycle (20 years)

Off Grid simulation model

Off Grid problem areas

• Cooking and water heating loads needs to be sourced

from gas and solar water heating

• Customers will generally refer to off grid supply as

inferior to grid supply

• Customers will tend to use energy intensive appliances

at different times of the day

“Smart” Microgrids

• Must use intelligent control for dispatching PV,

managing battery charge and discharge cycles and

perform load control

• Load limits is critical to manage the limited

generation and storage systems

• Must inform customers of state of system in a

simple and effective way and involve customers

from day 1

Research questions

1. What is the optimal microgrid

configuration needed to serve a

typical rural community with basic

energy needs?

2. How will the system cater for the

natural growth in consumption?

3. Should communities be allowed to use

any type of appliance?

4. Who will do the basic maintenance i.e

regularly clean solar panels?

5. Who will perform more complex

maintenance activities?

The off grid solution must be intelligent,

cost effective and be fit for purpose for

rural sites. Simple and easily deployable.

The system needs to modular and

expandable to cater for growth.

Community engagement is key to off grid

success and training on appliance usage

is critical.

First line maintenance must be a function

of community involvement and can be to

create local employment.

Second line maintenance contracts must

be in place and managed at a higher level.

Next steps

The simulation results will form the basis for

further Research and Development:

• Implementation of an off grid pilot project to serve as a

test bed

• A more detailed design of the system components

• Control system and load management

• Social study

• Community engagement and training

Conclusion

• Microgrids/off grid solutions can be effective

in supplementing the electrification program

• Community/social studies are part of the

solution and critical in ensuring the success

of the project

• Further work is required in exploring all the

options needed to deploy in South Africa.

Thank you

raj.chetty@eskom.co.za