Energy Storage for the bottom of the pyramid

Ananth Aravamudan SELCO

Setting the context…

• SELCO is an 18 year old social enterprise whose mission

is to provide sustainable energy services to the poor and

under-served

– Dr.Harish Hande, founder, won the Magsaysay Award in 2011

• SELCO has electrified, via solar, more than 150,000

households (more than half a million people)

– 30 branches and 200+ employees

• 90% of the systems are financed (mainly by banks, also

co-operatives, MFI’s, etc.)

• SELCO philosophy

– Solar energy system should be treated as an asset that is

bankable

• This implies high quality, long life and warranties that

match typical loan tenures

– Service is as important as sales

How do the economics work out?

Energy source for

lighting

Details Monthly

household

expenditure

Kerosene

Decentralized Solar

Energy

Household Level:

Rs. 8000 @ 12% for 5 yrs Rs. 180

6 liters (Rs. 14 per liter + Rs. 60 per liter) Rs. 270

SELCO-India in a snapshot

SELCO India

SELCO Solar Private Limited (1995)

- 32 branches - 3 states

- 200+ employees - Partnerships with

Financial institutions

Operations Mission Projects

SELCO Foundation (2010)

Experimenting with technology,

financing and community models

SELCO Labs

- Rural, Urban,

Education, Tribal

communities

Policy

Capturing the

Practitioners’

perspective

SELCO Incubation

Center (2012)

- 8 Incubatees

in 2012

- North and North

Eastern States

ENERGY STORAGE

AT SELCO

Solar Home Lighting Systems

Home Light Systems

Rural Home Basic Solar PV system working model

Energy Storage for HLS

• SELCO home lighting systems use tubular

flooded lead-acid batteries

• Designed for 3 day autonomy, never exceeding

20% depth of discharge

• Batteries rated at a discharge rate of C10

Energy Storage for HLS (contd…)

• Pros

– Locally manufactured, cost effective

– Field-proven, come with 5 years warranty

• Essential for bank loans

• Cons

– Require maintenance (distilled water top up every 4

months)

– Low energy density, bulky and heavy

– Transported in “wet” condition, since local handling of

“dry” batteries not possible in remote locations

• Many transporters won’t take these

Central charging models – street hawkers

Energy Centre, Tubrahalli, Bangalore

Mobile and lantern charging facility, Dharmastala Energy Centre Customers, Chitradurga

Energy Centre, Udupi

Central charging models – energy centres

Energy Storage for Central Charging

• Early models used small tubular lead acid

batteries (10 Ah – 15 Ah)

• More recent models use sealed lead acid

batteries

• Battery portability is a key factor

• In these systems, batteries are deep-cycled every

day, especially in slum homes

Energy Storage for Central Charging

(contd…)

• Pros of sealed lead acid

– Locally manufactured, cost effective

– Relatively lighter than tubular batteries

– No maintenance required

• Cons

– Poor cycle life, failures start from 6 months onwards

– Warranty is from 6 months to 1 year

– Use and throw

Light for Education - model

Light and battery

Charging station at School

Solar panel on school roof

Child studying at home

Energy Storage for LFE

• Light for Education uses NiMh or Li-ion batteries

• Storage ranges from 1500 – 2200 mAh

• Pros:

– Extremely portable and lightweight, fits into the child’s

pocket

– No risk of leakage or spillage

• Cons

– Works only for small loads like study lamp

– Cost is relatively high

Summary

• Our target communities need upgraded energy

storage technology!

• Fixed home lighting systems:

– Spill proof, yet highly reliable batteries

• Portable systems:

– Lightweight, high cycle life batteries

– Small cost increase can be afforded, but not a massive

one

Thank You