RE based Mini and Micro Grids – A Sustainable Solution

Renewable Energy (RE) based Mini and Micro Grids are the small-scale version of the conventional Grid. These have the potential to give electricity and livelihood access to the rural & remote areas of any country. This Mini-Micro Grids can be without RE as well. But here we will explain the RE based solution only, considering its huge potential not only from the environmental point of view but also from the income generating aspects as well. Here RE means primarily Solar PV and backed by any potential resource-based technologies like biomass, wind, small hydro, etc. (Solar PV Hybrid incorporates the latest technologies like smart meter, remote monitoring system and are typically designed to interconnect with the main grid). This is being called Third Generation Mini Grid.

The ESMAP Technical Report 014/19 defines Mini Grid as below: –

Mini grids are electric power generation and distribution systems that provide electricity to just a few customers in a remote settlement or bring power to hundreds of thousands of customers in a town or city. They can be fully isolated from the main grid or connected to it but able to intentionally isolate (“island”) themselves from the grid. Mini grids supply power to households, businesses, public institutions, and anchor clients, such as telecom towers and large agricultural processing facilities. They are designed to provide high-quality, reliable electricity.

The typical specification can be considered: –

• Mini Grids: A RE based electricity generator with a capacity of more than 10 kW
  • AC mini grids:
    • 220 V 1 phase – up to 10 kWp
    • 440 V 3 Phase – beyond 10 kWp

• Micro Grids: A RE based system with a capacity below 10 kW, supplying clean electricity to a cluster of houses in a remote area. DC generally generated through solar power is normally preferred where the loads are of low voltage/power, such as lighting, fans, radio, etc., and is closely located.
  • DC micro grids:
    • 24 V DC – up to 1 kWp
    • 72 V DC – above 1 kWp to 10 kWp

In last few years the price of Solar PV panels has been plummeting on regular basis and simultaneously the other components like storage, inverters, along with other RE technologies are becoming cost effective and technologically superior, the investment on such Solar hybrid systems are getting huge attractions worldwide. Still now Asia has the highest number of Mini Grids, but Africa has the highest potential in the coming time.

Goal 7 of the SDGs aims to ensure that everyone has access to affordable, reliable, and modern energy services by the year 2030. But, an estimated 650 million people—or 8 percent of the global population—will still lack access to electricity in 2030; 9 out of 10 of them will be in Sub-Saharan Africa. And, this third Generation Mini Grids are being seen as a hope.

References:

1. Mini & Micro Solar Grids- a beacon of hope for the RE sector- Akshay Urja, June 2017
2. Mini Grid for half a Billion people -ESMAP Technical Report 014/19