Intel has calculated that its Core processors have saved 20 Terawatt hours of energy over the last two years, this adds up to $2 billion in energy savings:
In 2006, Intel rolled out the Intel Core microprocessors for PCs, servers and laptops. We’ve also referred to this architectural shift as the “right hand turn” (the shift away from performance achieved primarily through clock-speed increases to improvements from the integration of additional processor cores on each chip). Intel’s engineers recently analyzed the difference in the power utilization of earlier generations of our processors, compared to the typical power utilization of today’s products - and considered the number of processors shipped and hours they were likely used in PCs, servers and laptops.
So what did we find? When we added up all the Watt-hours that were saved in the past 2 years as a result of Intel’s “right hand turn”, the calculations point to approximately 20 Terawatts hours less energy used, relative to what our prior generation of processors would have consumed in the same time window. Assuming an electricity cost of $0.10/kWhr (higher in some places, lower in others), this equates to $2B in energy cost savings to the global economy.