Studies on Chicago City Hall after installation showed that roof temperatures fell by up to 30 degrees C on hot summer days and surrounding areas were cooler by 9 degrees C. We know that with every degree less difference between internal and external temperature, the fuel bill can fall by up to 10%.

Smart power regulation means that spikes of electricity demand can be managed by automatically turning off certain devices in factories, offices and homes when the grid is under strain.  It also means that electricity pricing can be varied from hour to hour depending on demand. Power companies have huge challenges managing peak demand and the result is wasted energy and extra costs.  Take Australia:  on the hottest four days a year, energy use can jump by over 50% compared to the average.  10% of the entire generating capacity of the country is used for just four days a year.

[http://www.youtube.com/watch?v=wlv5-iuyriA 300 250]Windmills have been used for centuries – using wind to turn machinery.  Electricity generation using wind also has a long history, but has only taken off in the last three to five years, now growing 30% a year.   Wind already provides a peak global capacity greater than 100 gigawatts – to compare, the entire UK uses only a peak of 57 gigawatts.   Denmark produces 19% of electricity this way, Spain 9%, Ireland 6% and Germany 6%. The current US contribution of wind to electricity is only 1% but this could rise to 15% by 2020.

If used on a large scale, solar cells could significantly reduce carbon emissions.  If a total land area 1% of the size of Texas was covered in solar cells with 30% efficiency, it would provide enough to power the whole of America.  (National Renewable Energy Laboratory figures).