Q: How many processes are there in CMLCA?

A: Anything between 0 and 4 billion. CMLCA is a program, like MS-Word, it is not a database. It doesn't make sense to ask "How many documents are there in Word?", just because the program is empty, while you can open, create, and import an unlimited amount of documents. Likewise for CMLCA: it is empty, but you can open, create, and import an almost unlimited amount of processes. There are standard ways of importing process data, e.g. from ecoinvent.

Q: Which impact categories are covered are there in CMLCA?

A: Like above. CMLCA is empty, but you can open, create, and import an almost unlimited amount of impact categories. There are standard ways of importing characterisation factors and normalisation data, e.g. from ecoinvent.

Q: Why did you develop CMLCA?

A: First of all, I needed software for supporting a university course. At that time, all "normal" software would cost you a lot of money, license agreements, and so on. But at some stage, my colleagues started to use the program for scientific work, students for case studies in an internship, and so on. That created new demands: import of databases, advanced options, and so on. At the same time, I was using it to exploit new developments, such as the use of analytical error propagation, and CMLCA was a perfect vehicle for such exercises.

Q: Is there other free software for LCA?

A: Yes there is. Two examples that I know are the openLCA Framework and the brightway LCA model. If you know more, please inform me.

Q: Is CMLCA open source?

A: No, it is not. Perhaps that will change in future. But most of the code is quite uninteresting, writing information to the screen, etc. The more interesting parts have been documented in scientific books and articles; see What is CMLCA?

Q: How has CMLCA been programmed?

A: The present version is compiled with Borland Embarcadero RAD Studio 2010 (Delphi). Most of the code is in Object oriented pascal (OOP), but obviously some smaller fragments of API calls and even Assembler do specific jobs. Altogether, the code is some hundred thousands of lines.

Q: Who has programmed CMLCA?

A: It was Reinout Heijungs, from CML, for the largest part. Some routines were taken from established books, like Numerical Recipes, and some snippets were copied from various websites, especially on the difficult parts of the Windows operating system.

Q: The meta-information of imported data (ecoinvent, US-LCI, ELCD) is gone.

A: Right. In older versions, it was there, and you could read and even edit it. At some stage, I deleted this. The reason is that the prime task of CMLCA is to support the calculation steps, and that the program became sort of overloaded with more administrative information, like fax number of data suppliers. Moreover, it became increasingly difficult to maintain, with two versions of EcoSpold, two versions of ELCD, etc.

Q: I run out of memory while importing ecoinvent data.

A: In importing ecoinvent, you should understand that you can either import the unit processes or the cradle-to-gate inventories. The unit processes are typically of size 5-20 kB, while almost all cradle-to-gates are 500 kB. For the unit processes, you typically need to import all, because each links to another. For the cradle-to-gates, you can select only those that you need directly, as all upstream impacts are included already. Importing all 4000 unit processes can be done, but I guess you need 1 GB RAM. Importing all cradle-to-gates may be a problem.

Q: I have a progress bar which doesn't seem to do anything.

A: Probably, you've encountered a bug. In most cases, you may click the small X at the top right corner, and proceed as before. I recommend, however, to save your data with a new filename, to quit CMLCA, and start it again.

Q: Some parts are mysterious to me.

A: Most screens now allow you to press F1 to get help, but for a small number of screens this feature is still in development.

Q: I have another question.

A: Please email me; see help and support.