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Economic allocation calculations

Posted: 09 Apr 2015 17:58
by abenoist
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

Re: Economic allocation calculations

Posted: 10 Apr 2015 11:08
by aciroth
Hi, you are right this is indeed a bug. We convert to the reference property straight away here and do not take into account that costs are not the reference property. Will be fixed with the next beta release!
Thanks again, best wishes,
Andreas

Re: Economic allocation calculations

Posted: 10 Apr 2015 12:33
by abenoist
Perfect! Thanks again for openLCA!