Monday 25 June 2018

It's Hot in Arizona!


Salt River Project, or SRP as it is now more commonly known, is an innovative electricity supplier in Arizona USA. They have a wide range of demand-related tariffs, including a time-of-use tariff which has at its most extreme, a factor of three difference between peak and off-peak costs per kWh in July and August.
This highlights the value and in this case the relative ease of substantial time-shifting of air-conditioning. Environmentally conscious Arizonans have a number of options:
  • Build houses with high thermal mass as well as high insulation, so that cooling can be done outside of peak times, and advantage can be taken of the large differences between day and night temperatures in desert areas.
  • Use storage aircon to build up ice as a store of coolness before peak times.
  • Start cooling the house well before peak times and tolerate some increase in temperature during the peak.
  • Use PV to generate electricity for cooling 
Coincidentally, Arizona is where PV can best be generated to meet UK's winter peak, as their solar midday occurs during our evening peak. So the PV they use during their summer could supply our electricity in winter.

If you want to avoid the cost of a Northern hemisphere supergrid to allow this, then shift your time of use and get others to do the same!