Solar Powered Lights

• Solar panels are great, if there's sun to charge them.Jupiterimages/Photos.com/Getty Images
  
  Solar powered street lights have been introduced in parts of America, Australia and across Europe. They tap the power of the sun to run the street light. The problem with this is that solar panels rely on, well, the sun. When you have a cloudy day, or several cloudy days, when you're in the middle of winter or if you live in a region that just does not get much sun, the efficiency of solar lights is significantly reduced. This is a huge disadvantage and makes the technology unreliable at best. To combat this, many lights are now being installed with solar panels and a back-up battery supply.
  
  

Induction Lights

• Street lights made in China? Good for the environment but not for economic growth.Thomas Northcut/Photodisc/Getty Images
  
  Induction lights are similar to LEDs in that they are a low-energy light which consumes a lot less electricity and costs a lot less to run. However, they too have some disadvantages. As with many green technologies, they have a high initial cost. First, they are often bigger and up to four times heavier than traditional lights. This means that to install them in street lights means redesigning the entire light fixture. Furthermore, the technology is mostly made in and imported from China. Chinese products have a reputation of being cheaply made and workers are often paid incredibly low wages. These lights should be both ecologically and human-rights friendly in order to be used in street lights.
  
  

LED Lights

• Keeping our parks lit at night needn't cost the Earth.Thomas Northcut/Photodisc/Getty Images
  
  LED lights are already being used in a great many homes and businesses. Using them in street luminaires as well seems like a good idea. There are two main disadvantages to this. The first, once again, is cost. LED lamps are pricey. While local governments will save a lot of money in the long term, the initial cost will be very high. The second disadvantage is that LED lights are still consuming electricity and burning fossil fuels, rather than accessing alternative energy sources.
  
  

Overall Disadvantages

• Green technologies have come a long way. However, many are still not being produced in large quantities, particularly in the United States. This makes them expensive and, in some areas, difficult to find.
  
  Also, the lighting industry simply does not know how long these lights will last. According to the U.S Department of Energy, LEDs "are often integrated permanently into the fixture, making their replacement difficult or impossible". Furthermore, the LED light output diminishes over time and depends a great deal on thermal conditions. This makes for a somewhat unreliable light. It is clear that more testing is required before green lights can be used to replace all street lights in the future.