To ascertain how we can solve the problem of rural electrification using mini-grids, I recently visited Akpabom community in Onna Local Government area of Akwa Ibom State where a mini-grid is used to power the community.
Mini grids, also sometimes referred to as a “micro grid or isolated grid”, can be defined as a set of electricity generators and possibly energy storage systems interconnected to a distribution network that supplies electricity to a localized group of customers.
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“They involve small-scale electricity generation (10 kW to 10MW) which serves a limited number of consumers via a distribution grid that can operate in isolation from national electricity transmission networks.” As documented in energypedia.
Akpabom community is located within the riverine area of Onna Local Government Area. Totally secluded from the closest community by a water boundary, though a bridge has now been fixed creating access to the community.
How the dwellers feel about the mini-grid project
The dwellers lamented how the community had been in darkness before the installation of the mini grid.
“We have suffered for years before the installation of this mini-grid. Our community was not even linked to the epileptic main grid until God visited us and gave us this mini-grid. There is nothing you can do with light that this light cannot power”, a residence narrated.
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The residents were satisfied and even testified that the electricity could power welding machines and there is nothing they could do with power supply from the main grid that they could not accomplish with the supply they get presently from the mini-grid.
Mini-grids have a unique feature as they can operate autonomously without being connected to a centralized grid. However, the mini-grid may be designed to interconnect with the central grid which means it operates under normal conditions as part of the central grid with disconnection occurring only if power quality needs to be maintained.
The system used by the community I visited was the isolated method where the mini-grid generates power and is shared within the community without linking to the main grid.
The plant is a 100KWP Solar Mini Grid Electrification project for the community. Powered by the Federal Government of Nigeria under the Rural Electrification Agency while the investor/project developer is GVE Project Limited.
Sizing
There is no one single definition about the size of mini-grids. Some organizations define mini-grids in terms of the generation capacity i.e. between 10 kW to 10 MW. Others define it in terms of customers reached i.e. mini-grids reaching 20-100 customers are called micro mini-grids and mini-grids reaching over 500 customers are called full mini-grids.
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A general consensus is that mini-grids should supply more than a few kW of electricity to multiple consumers such as community, hospitals or schools.
Technologies used in building Mini-Grids
Mini-grids can be powered with different technologies such as solar, hydro, biomass or wind and are also coupled with energy storage systems such as batteries. The most common types of mini-grid technologies are:
- Solar mini-grids: Solar mini-grids are gaining popularity due to the falling cost of PV modules worldwide. Since they can generate electricity only in the day time, battery storage is required to meet the peak demand at night.
- Wind mini-grids: When the wind blows through the turbine, the wind’s kinetic energy is converted into electrical energy. These mini-grids are site specific and depend on the wind speed.
- Hydro mini-grids (MHP): MHP has the lowest levelized cost of generation and is at par with grid electricity. Unlike large hydropower, they do not require a dam/reservoir for water storage. They are mostly run-of-river and therefore have very little environmental impacts. The water flows from a higher elevation to the turbines at a lower elevation via a penstock. The turbines then rotate to generate electricity. The electricity generation depends on the water flow and also require a certain elevation. This makes MHP restrictive to a particular geography.
- Hybrid mini-grids: Mini-grids with renewables sources when coupled with non-renewable sources such as diesel systems or with other renewable sources are called hybrid mini-grids. These mini-grids are flexible as they can generate power on demand. Examples of hybrid systems are solar-diesel mini-grids and solar biomass mini-grids.
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Impact of mini-grids within our communities
Implementation of mini-grids have proved to have a positive social impact by fostering and improving the local governance structure through the involvement of the community in the decision making process linked with the energy system.
Furthermore, mini-grids are often the only economically viable option of electrifying rural communities. There are hundreds of diesel-based isolated grids worldwide which lend themselves to be retrofitted with renewable energy technologies.
Opportunities
There are a lot of opportunities that have been observed with mini-grid systems:
- They can be used to increase the reliability of electricity supply. Due to their small scale in nature and enhanced local level ownership of physical infrastructure or management, power theft which is a commonly associated with supply from the main (centralised) grid systems can be reduced.
- Reliability of supply is generally greater from hybrid mini-grid systems as compared to a single technology. This not only lowers the net costs over the lifetime of a project, but also ensures availability of power when one system is not working.
- There is environmental improvement from the use of mini-grids. This is in terms of efficiency and reduction in carbon emissions. Hybrid mini-grid systems, for example, often incorporate a 75-99% renewable supply.
- Economic assessments indicate that of the renewable technologies available, biogas, geothermal, wind and micro-hydro systems costing US¢6-15/kWh are the potential least-cost generation options for mini-grids in developing countries, this however assumes that sufficient renewable energy resources are available.
- Biogas digesters and biomass gasifiers are particularly promising from this economic perspective; this is because of their high capacity factor and availability in size range matched to mini-grid load. Geothermal on the other hand also appears economically viable for countries that have geothermal resources although it is limited to larger grid connected systems.
- For countries where the grid system is not well developed and there is a vibrant private sector, mini-grids provide opportunities and they are adaptable due to the fact that they can be connected to the grid as they expand.
- Conversely as the cost of fossil fuel increases, mini-grid systems are becoming more economically attractive as the cost of renewable energy resources decrease. However subsidies are still required for the different schemes but they are a smaller percentage of the investment than on-grid subsidies.
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What Next?
You can see the excitement in the expression of the villagers. The youth leader affirmed time without number that God has visited. “With just two thousand naira you can power your home for 1 month.”
Since this solution has worked perfectly well with the said community, I will suggest the government takes more proactive measures in curbing the power associated problems by giving more licenses to companies who are capable of providing this source of electricity to our communities.
Licensing only one company to supply power to the entire state leads to monopoly. Presently, communities that are connected to PHED laments no supply of electricity while estimated bills are made available at the end of every month.
Mini-grids with higher capacity could be the way forward in the nearest future. Presently with my experience at Akpabom in Onna Local Government Area, mini grids are the way forward if we must consider rural electrification project in earnest.
This survey was sponsored by NPN
