23-29 August 2013 #670

Seeing the light of day (at night)

LED lights and lithium batteries will revolutionise solar lighting systems in Nepal

When you see the new generation of compact solar lighting you think why no one thought of it before. Well, for one, the technology wasn’t there before. The reason solar lighting was so expensive and bulky was because photovoltaic cells were till recently unaffordable. And since solar works only in the daytime, battery storage meant large and heavy lead or SLR tubulars with limited lifespan.

The time has now come. Solar lighting has now become small, light, compact, and more affordable. The new technology is set to revolutionise off-grid outdoor lighting for streets, courtyards, parks, and parking lots. All this because the price of PV panels has come crashing down and storage has become lighter and smaller due to lithium ion batteries.

Future Green Energy is one of the new Nepali companies specialising in compact outdoor lighting systems and after you see what they have to offer you wonder why we are still stuck with obsolete lead-solar systems. Even grid-powered sodium vapour lights are now out-of-date.

Because power cuts are here to stay in Nepal for at least another five years, one installs solar systems not just to make a green statement but because there is no choice. In fact, some of the new systems are even more useful for Kathmandu offices and residences than for rural areas.

“Solar is not just about being environmentally friendly or for energy saving,” explains Rajan Rayamajhi of Future Green Energy, “it is sometimes the only solution.”

To be sure, solar lighting has been with us for decades. Nepal’s rural areas have benefited from government subsidised household solar schemes, villages off the national grid have depended on solar, and telecom operators have used photovoltaics to power towers in remote areas. But they all needed heavy truck batteries to store power for night lighting.

No more. The Chinese company Leadsun’s five watt stand-alone, off-grid street light system can be installed in 10 minutes on an existing pole. The top panel has PV cells that charge an in-built lithium phosphorous battery all day, the LED heads switch on automatically at dusk and turn off after dawn, and a motion sensor keeps light on low power until movement is detected. But the beauty is that it uses a tenth of the energy for the same lumen power from free-of-cost solar energy (see table). A range of similar systems are available for courtyards and parking lots with lower wattage and even lower costs.

The smallest of these is a one watt Eco Light that gives the same lumen power as a 60 watt bulb that can be screwed on to the wall of a house. It has a sleek 4x6x2 inch weather-proof panel that has a PV cell, a lithium ion battery, a charger, motion sensor, and light detector: all for Rs 2,500.

Future Green Energy also markets home lighting solutions that will make existing rural solar systems obsolete. For example, its all-in-one solar home lighting kit has three 4 watt LED lamps with an USB output device to charge mobiles. No heavy truck batteries to lug to remote areas. A larger system that can power more lamps and also charge laptops would actually be quite useful in Kathmandu for the winter ahead when daily 14 hours of load-shedding is anticipated.

“These things are so versatile, we can light up a large section of Nepal overnight,” says Anudan Rana of Future Green Energy, “you save money on transportation of heavy batteries, there are no environmental problems from disposing lead cells, and the lithium ion batteries last longer.”

However, the government and municipality don’t seem to have woken up to the potential of LED head-lithium battery combo panels and are still pushing the troublesome and bulky lead-acetate and tubular batteries.

Future Green Energy

www.fge.com.np

+977 1 5549252