Trinidad and Tobago - GoldWindSolar

Connectsun is working with GoldWindSolar, a Joint Venture between Trinidadian firms, Smart Energy and Precision Power & Air on a solar street lighting project located on a private development yet to break ground in Port of Spain. In this scenario, solar street lighting can be advantageous in the long run considering the costs of the alternative. Not only are we talking about years of recurring cost through electric bills, but the cost to bury cables to provide them power in the first place is an expensive task.

The challenge is locating the street lights at an appropriate distance apart to minimize the number lights needed, but still achieve the appropriate illuminance. A common mistake is not understanding the difference between a LUMEN and a FOOTCANDLE.

Just because a light gives off more lumens and is brighter at the light source, does not mean the light is illuminating a far away surface as well as another light with lower lumens, but a better footcandle rating. A Footcandle is defined by the luminous flux through a unit sphere (1ft radius) one foot away from the light source. Footcandles are still used, but sparingly. A more common metric is a LUX, defined as 1 footcandle = 10.76 lumen/m2. The Iluminating Engineer's Society (IES) publishes rules of thumbs for different lighting applications. For a residential project, we are trying to achieve between 3-8 lux. This means we can space the lights roughly 9-10 meters apart alternating on each side of the road so as not to illuminate lower than the minimum lux.

Lighting only accounts for between 10-15% of our typical electrical demand, but it is low hanging fruit. Some LED bulbs have a lifetime, no questions asked guarantee and while CFLs show the best returns on investment. In this particular project, lights are necessary and will account for a significant expense over the course of the development's lifetime. Unfortunately like most long term investments, initial capital outlay will be the issue.