Economic allocation calculations
Posted: 09 Apr 2015 17:58
Dear all,
First, thanks a lot for this open LCA software!
I had some issues with economic allocation calculations and I think it may be a bug. I found the same thing in the comprehensive user manual (1.2, March 2015) and in the software.
Page 34 and Figure 37, there is an example of economic allocation. A CHP process (Combined Heat & Power) produces 2 MJ electricity and 1 MJ heat. Market values are 0.79 €/MJ of electricity, and 0.36 €/MJ of heat. My own calculation for allocation factors would be, for electricity for instance:
Electricity allocation factor = (Economic benefit from electricity) / (Total economic benefit) = 2 MJ * 0.79 €/MJ / (2 * 0.79 + 1 * 0.36) = 81%.
openLCA finds an allocation factor of 47%, and I think it comes from the calculation : (2 MJ / 0.79 €/MJ) / (2/0.79 + 1/0.36) = 48%. Meaning that the higher the market value, the lower the allocation factor. The same problem occurs in the software itself with other examples.
Thank you
Best regards
First, thanks a lot for this open LCA software!
I had some issues with economic allocation calculations and I think it may be a bug. I found the same thing in the comprehensive user manual (1.2, March 2015) and in the software.
Page 34 and Figure 37, there is an example of economic allocation. A CHP process (Combined Heat & Power) produces 2 MJ electricity and 1 MJ heat. Market values are 0.79 €/MJ of electricity, and 0.36 €/MJ of heat. My own calculation for allocation factors would be, for electricity for instance:
Electricity allocation factor = (Economic benefit from electricity) / (Total economic benefit) = 2 MJ * 0.79 €/MJ / (2 * 0.79 + 1 * 0.36) = 81%.
openLCA finds an allocation factor of 47%, and I think it comes from the calculation : (2 MJ / 0.79 €/MJ) / (2/0.79 + 1/0.36) = 48%. Meaning that the higher the market value, the lower the allocation factor. The same problem occurs in the software itself with other examples.
Thank you
Best regards