Mini-grids are an important component in the renewable energy mix. They have been considered to be a sustainable and cost-effective solution for providing reliable energy access to various communities across the planet. Mini-grids have become increasingly popular in the recent years due to:
To assist in technology differentiation, the Hydro Empowerment Network (HPNET) in partnership with Swiss Resource Centre and Consultancies for Development (SKAT) have developed the Mini-Grid Technology Differentiation Table. The tool was originally released in HPNET’s 2017 Mini-Grid Webinar Series and recently updated to ensure a detailed overview of the various mini-grid technologies.
- the enormous cost of grid extension in rural areas
- the limitations of household systems (e.g. solar home systems).
To assist in technology differentiation, the Hydro Empowerment Network (HPNET) in partnership with Swiss Resource Centre and Consultancies for Development (SKAT) have developed the Mini-Grid Technology Differentiation Table. The tool was originally released in HPNET’s 2017 Mini-Grid Webinar Series and recently updated to ensure a detailed overview of the various mini-grid technologies.
Technology Differentiation Table developed by SKAT and HPNET. (Click on image to access full table).
Mini-Grid Technology Differentiation
The table differentiates mini-grid technologies based on system design, advantages, limitations, productive end use, resource assessment, spare part availability and investment costs of all the mini-grid technologies. Key insights include:
- Range of investment, which refers to the monetary investment required for generation and distribution, is the lowest for diesel and hydro mini-grids, while solar-battery, biomass gasifier and wind battery-based systems can go up to even USD 13,000/kW, compared to as low as USD 300/kW and USD 500/kW for diesel and hydro mini-grids respectively. However, despite the low investment costs, diesel has high operational and environmental costs in the long run.
- The operations and maintenance (O&M) costs (with assumptions) is on average 10% roughly for all technologies, except hydro mini-grids which incur only 2-5% of investment.
- The percentage of local contribution is only 5% in solar-battery and diesel mini-grids, while it is around 60%, 70% and 95% for wind, hydro, and biomass mini-grids, respectively. Higher local contribution means increased local job creation.
- Each technology has its own advantages. For instance, hydro mini-grids have low cost per kW; abundant sun in most places means solar is versatile; easy storage biomass resource allows optimum efficiency for gasifiers; and local manufacturing leading to lower O&M costs for wind and hydro can be beneficial.
- There are certain limitations associated with each technology. Accessing funds for high initial investment is an issue for both hydro and solar mini-grids, while pre-mature technology is a hindrance facing the biomass gasifier. Batteries in wind systems face high temporal variability and high maintenance costs, while diesel has negative environmental impacts due to carbon emissions.
- Providing electricity for productive end use, such as agri-processing, irrigation purposes, and various mills/local industry, generates optimal impact and sustainability of mini-grids. Mini-grids that are not dependent on batteries -- such as hydro and biomass mini-grids -- are ideal for powering motorized loads.
Advantages of Hydro Mini-Grids
Micro hydro images from HPNET members.
Although there are certain challenges associated with hydro mini systems, including relatively longer resource assessment and installation periods, hydro mini-grids have the following advantages:
- Hydro mini-grids typically produce 3-4 times as much kWh per kW installed. Moreover, hydro mini-grids generate electricity 24 hours, compared to solar and wind that are limited to 6-12 hours on average, depending on the availability and fluctuation of wind (average of 8 hours/day).
- Local manufacturing brings down the cost of hydro mini-grids and increases employment. Hydro mini-grids are especially apt for local manufacturing, since most components can be developed in a local metalworks fabrication facility.
- Although hydro mini-grids have a large range of investment costs (USD 500 - USD 10,000/kW) based on accessibility and the local terrain, most easy-to-access systems have low investment and generation costs.
- Low cost of energy enables greater productive end uses, and higher revenue from productive loads means lower cost energy for everyone.
A micro hydro plant in Nepal. Credit: Sunir Pandey - Hydro mini-grids create opportunities for dynamic tariff structures to increase sale of electricity during off-peak hours. For example, a bakery or induction casting facility can be motivated to utilize electricity during off peak hours with reduced tariff.
- Community micro hydro builds up of local social capital. Hydro mini-grids transform the traditional models of energy of social assets into social enterprise. This means that they improve the social and environmental well-being of the communities, maximize social impact, and generate profits for co-owners.
- Hydro mini-grids are especially conducive for grid interconnection, reducing voltage drops in the main grid and generating income for the MHP community. Moreover, the revenue from the project can multiply in the case of later grid interconnection.
A micro hydro village in Northern Pakistan. Credit: Sarhad Rural Support Programme (SRSP)
