CLEAN invites proposals for storage-backed mini grids in India

The Clean Energy Access Network (CLEAN) has issued a request for proposals (RfP) to lithium-ion (li-ion) battery manufacturers to demonstrate their battery technology for use in mini grids or decentralized renewable energy applications in India.

CLEAN is looking for mini grids pilots in the range of 15-20 kW generating around 80 – 100 kWh of energy per day.

CLEAN is promoting li-ion by stating that it has encountered problems associated with valve-regulated lead acid batteries (VRLA). Lead acid batteries are proving less economical for storage, CLEAN claims, especially for renewables-based mini and micro grids in India. Lead acid batteries will have an adverse effect because of temperature increases and will, ultimately, see diminished output. This is a particularly acute problem in India where tropical conditions are normal.

CLEAN also states that lead acid solar battery users continuously need to keep track of battery voltage, water levels, overcharge functions and routine electrolyte maintenance.

The tender aims to develop pilot projects with mini grid players and solar home systems in collaboration with li-ion battery system OEMs.

Where necessary, criteria for bidders states that it should be a manufacturer of li-ion batteries based on NMC (Nickel Manganese Cobalt) chemistry. The tender is to help operators of solar power plants to achieve maximum generation and output.

According to CLEAN, “The pilot will be beneficial for the entire supply chain mainly due to enhanced electric power quality, dependability, and better grid stability. Thus, lowering renewable energy intermittency, with increased user-friendliness and accessibility of electrical energy in remote places and reduction in harmful emissions.”

The United States Agency for International Development (USAID) will support the projects financially.

The proposals are due on October 20, 2017.

Li-ion comparison with VRLA

CLEAN has demonstrated the various benefits of li-ion battery over VRLA batteries (see table), and states: “Though they are used to power the same applications, that is where the similarity between lithium-ion and lead-acid batteries ends.”

S. No.ParameterTraditional VRLALithium Ion
1Charging Time7 – 8 Hours~1.5 – 2 Hours
2Usable capacity (Depth of Discharge, DOD)50%>90%
3Life cycles~ 12004000 ~ 5000
4Efficiency (Charge/Discharge)~ 75%~ 95%
5Space requirement in percentage100%~33%


The association also highlighted the environmental benefits and much smaller footprint, thanks to higher energy density, of li-ion over VRLA batteries.

The only place where lithium-ion batteries lost against VRLA is the high upfront cost. However, the actual cost of ownership is far less than lead acid when considering lifespan and performance.

Li-Ion can be equipped with battery management system – health monitoring, self-protection, status indication and overcharge protection, whereas, these functions are not presently available with VRLA.