* Energy Recovery Street Light

Section of combination-power source street light

What if…

Step 1 : Take street light.

Step 2 : Fit the street light with heat and light (thermo- and photo-voltaic) collectors which could capture some of the wasted light and heat spillage from the bulb, applied either to the inside of the glass diffuser of the light itself, or on the reflector which needs to be opaque anyway. Crucially, the distance from light source to light capture is not much at all, meaning that there would be a higher efficiency of recycled energy both in the high lumens capture of light from the bulb, and also in the minimal resistance-based wastage in transmission from the collector to the storage medium and back to the bulb due to the short distances involved. Thin and flexible photovoltaics (PV)s on the top housing of the light would harness solar power during the day.

Step 3 : The captured energy recharges a battery attached to the base of the bulb.

Step 4 : Once the battery is full, the street light changes its power source to the battery.

Step 5 : Once the battery is exhausted, the street light reverts to mains power.

These adjustments would be almost invisible to the naked eye and would aid in reducing overall power consumption.

Solar powered street lights already exist, but energy savings could be maximised by combining the following into the design:

a) Adding a movement sensor that would dim the light when there was no movement sensed in the vicinity of the street light after a certain period of time.

b) Using LED light sources that consume less power in the first place.

c) Using a thin, flexible and cheap solar technology such as Nanosolar’s SolarPly™. Because it is flexible, it allows the PV component to be more sculpted aesthetically to the form of the light housing, maximising possible solar collection.

Nanosolar : SolarPly™ / Nanoparticle Ink

The development of SolarPly™ is also significant in that it is 100 times faster to produce than existing solar technologies and uses 100 times less material than silicon wafer panels. This of course leads to a whopping potential 5-10 times cost saving over current panel prices. The flexibility comes from a conducting foil-based approach, while the manufacturing cost can be so reduced over traditional silicon panel production by the way it is produced off an assembly line, essentially ‘printed’ from rolls in mile-long sheets and then cut to size.

Key to this innovation is the Nanoparticle ink used, applied homogeneously, that evenly distributes the conducting elements in the semiconducting medium so that the conducting path does not need to be so rigid. So even if there is a flaw in the application of the ink, or damage to part of the panel, it will still work because, being a ‘field’, the current should find its way to the converter through any direction where the ink has been applied rather than through a specific predetermined path.

The SolarPly™ could be integrated either to the top of the light (as in the illustration above) or could even be used as a manufacturing material to clad the entire light. The holy grail of this type of Nanoparticle Ink approach of course would be to have a PV ‘paint’ that could be applied as a coating to virtually any surface. It then follows that you could add it to any building with enough exposed area, both new or existing, to harness solar energy – though many technical hurdles regarding the capture and channelling of the energy to somewhere useful still has to be addressed.

Cost savings would still need to be calculated, but because of the combination nature of the energy collection, the street light could feasibly end up being power neutral.

Aesthetically Invisible

Further reading of existing solutions:

Bright Green Energy

Sollatek

Carmanah Lighting