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:

• the enormous cost of grid extension in rural areas
• the limitations of household systems (e.g. solar home systems).
  
  

Within the mini-grid spectrum, it is pertinent to note that there exist various mini-grid technologies, i.e. solar, wind, biogas, diesel and hydro mini-grids, being implemented for energy access.  In fact the nature of mini-grid development is such that systems must be customized to meet each community’s energy demand, resource availability, and governance structures. So while mini-grid development partners tend to be technology agnostic, it is also extremely crucial to differentiate between technologies, as each has its own strengths, challenges, investment costs, price of energy, and operational management models.

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.

​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:
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• 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.

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• 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 

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: 
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• 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.

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• ​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. 

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• 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 common cause of power outages in communities with micro hydropower systems is when the demand on the system is too high. Residents are often unaware of their energy usage leading them to connect more appliances than can be supported. This causes the safety systems to disconnect the supply, causing the shutdown.

Through collaboration between Tonibung, Green Empowerment and HPNET, and funding from the WISIONS Sustainable Energy Project Support (SEPS) grant, an open-source design for the device was conceptualized, aimed at enabling local practitioners to manufacture it themselves.

The load indicator was envisioned to be a simple plug-and-play device that can be fitted in any regular household socket. When the micro hydropower system is nearing a critical threshold, the device will sound an alarm warning consumers that further usage of appliances will overload the system and cause a power outage.

Learn to build your own Canary Load Indicator Device here at this link.
Learn about Open Source Technology for Community-based Renewable Energy here at this link. ​

Are you a pico, micro, or mini hydro fabricator looking for video tutorials?
Or perhaps the designer of an off-grid energy program, looking for best-practices for micro hydro?
Are you a funding agency seeking case studies on community-based micro hydro?  
Are you a local practitioners' association wanting to share your work with a wider audience?
Maybe you are a civil society organization searching for hands-on experts or micro hydro data?

If so and otherwise, we have just the tool for you -- the Micro/Mini Hydropower Library (MHL)!  The library is a result of HPNET partnering with energypedia, a platform for collaborative exchange on renewable energy, to address HPNET members' request for an online, peer-to-peer knowledge exchange portal. ​

What's in it?
The library features

• Knowledge products ranging from publications, case studies, manuals, policies, and multi-media, e.g. videos, photos, and simulation tools!
• Lists of consultants, developers, funding agencies, policy experts, programs, and suppliers working on pico, micro, and mini hydro.
• Thematic search filters, displaying results on a world map. 
• Easy-to-use interface, where any user can also upload and download publications.

​How to get started?
With a few simple steps. :)

1.  Get a login on energypedia here.
2.  Explore MHL's home page.
3.  Take a quick browse.
4.  Search by country, theme, and type of knowledge product.
5.  Add your work to the library!  (If you're a developer, supplier, or consultant, be sure to add to the Contact Lists, found under Filter 2, on the Search page.

Thank you!
The tool was made possible by support and inspiration from WISIONS, Practical Action Nepal, EnDev Indonesia, the energypedia team, and the members of HPNET.  A special thank you to energypedia's intern Mr. Kumar Avinash and HPNET's volunteers Ms. Margaret Hegwood, Ms. Tha Zin,​ and Ms. Sona Vaghela for initial uploads. 

Spread the Word :)
Please share the word on MHL, as the more people use and add to it, the more it can offer.  We would also appreciate your comments to improve MHL in coming months.  Please write to us here.
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