Wednesday, April 14, 2010

When 1% of Energy Conversion Loss Is Avoided

What will happen if 1% of energy conversion losses are avoided all over the energy network?
Engineers (Jonathan M. Cullen and Julian M. Allwood) in the University of Cambridge calculated the huge potential of the 1% loss reduction on the global energy supply and demand.
Initially, they computed the maximum energy savings that can be brought by using theoretically most-efficient energy conversion devices. Their conclusion is, theoretically, we need only 11% of current energy supply.
How about realistically?
They propose the case that the conversion loss for each device is reduced by 1%. This energy loss reduction results in 33 exajoules (EJ; 1018 J) of energy savings, compared to 420 EJ of the theoretical maximum savings. The specific number is not so important (In 2005, 33 EJ was 7% of the global energy demand 475 EJ or slightly less than China's energy demand, though.). What is amazing in this analysis is the relative difference between upstream and downstream energy saving potentials. While upstream (fuel transformation and electricity generation) efficiency gain saves 5 EJ, downstream (end-use conversion devices) efficiency gain can bring about 28 EJ savings.
This 5:28 ratio might suggest a shift in priorities in energy policy.

Source: Cullen, J. M., &  Allwood, J. M. (2010). Theoretical efficiency limits for energy conversion devices. Energy, 35(5), 2059-2069. Retrieved from

This article provides a fantastic diagram (Sankey diagram) of global energy chains, which is also found in Mr. Cullen's poster at

No comments:

Post a Comment