The City of Kigali could save more than Rwf954 million annually if it rolls out energy saving street lamps, a city engineer has said.

Eng. Evode Nkusi, the City officer for energy and public lighting, said the current bulk of the public lighting system comprises high pressure sodium (HPS) lamps that consume a lot of power.

The plan is to pull them down and install "light-emitting diodes (LEDs) with latest energy saving technology and use 40 to 60 per cent less energy compared to the HPS lamps.”

"But it will take time. We have already covered nine kilometers: the road section from Kanogo-Poids Lourd-Nyabugogo-Gitikinyoni to replace HPS with LED. The project could take five years,” Nkusi said.

For the last 20 years, most city lights are of high pressure types of 250watts (90 per cent) and 400watts (10 per cent). The plan is to replace these with energy saving types of 100watts and 180 watts, respectively.

"By replacing them in 265 kilometres of public roads in the city, we will save Rwf954,889,056 every year,” he said.

A draft cost comparison of energy savers and high pressure lamps on city streets, done by City engineers, indicates that the former uses Rwf508.9 million per year, while the latter consumes Rwf1.5 billion.

A high pressure lamp could consume 400watts, in a day, while an energy saver lamp consumes 112watts.

Apart from saving big on energy, energy saver lamps are long-lasting and emit better light.

In addition, while the lifespan of high pressure lamps is 10,000 hours the energy saver lamps are said to go up to 50,000 hours.

Normal power installation for a kilometre-network can cost between Rwf40 million and Rwf50 million, depending on whether it is an underground or overhead installation–the former is cheaper but often avoided in the city given the constant expansions and restructuring.

Currently, the City has 265 kilometres of road network covered with public lighting. The plan is to light the entire 350 kilometre-network (tarmac and stone paved roads) and any new roads.

Solar

The City’s public lighting plan will also tap into solar and, in its 2014/15 plan, the initial phase between Nyanza memorial in Kicukiro and Gahanga centre, covers four kilometres.

"For the second phase, we’ll first establish roads where the current power source is far away from the main grid. This project (solar) also is feasible,” Nkusi said.

"Even if it is costly, it is cost effective in the long run. Research shows that we can produce four to six watts per square meter per day, which is reasonably enough. The country’s climate favours solar power generation,” Nkusi said.

The City has a pilot project on Mt. Jali which feeds 250Kw into the national grid and a new one near the Sonatubes area, in Kicukiro.

Rwanda generates 110MW (17 per cent of domestic accessibility) of electricity. The government plans to generate 1,000MW by end 2017 and boost access from of households to 70 per cent.