Biosphere

So far, we have described processes exchanging products within the technosphere. In LCA, however, we also need to model processes exchanging substances with the biosphere. In our tool, there are three kinds of biosphere exchanges:

• emissions, which are substances emitted to the biosphere (like products for the technosphere)
• resources, which are substances taken from the biosphere (like inputs for the technosphere)
• land use, which is a special type of resource where you use a surface of land in a certain way.

By now, you should be familiar enough with the language to guess how we will declare these exchanges in our process: using... keywords and blocks of course! Let us add an emission to our running example: baking in a wood oven produces wood smoke as part of the combustion process.

process bake {
    products {
        1 kg bread
    }
    inputs {
        1 kg flour
    }
    emissions {
        1 m3  wood_smoke (compartment="air")
    }
}

process mill {
    products {
        1 kg flour
    }
    inputs {
        2 kg wheat
    }
}

Try and add 1 kg of wood needed as a resource for the baking process. The tool will notify you if what you have written is not well defined: try to use those errors to find the proper solution!

process bake {
    products {
        1 kg bread
    }
    inputs {
        1 kg flour
    }
    emissions {
        50 m3 wood_smoke (compartment="air")
    }
    resources {
        1 kg wood
    }
}

process mill {
    products {
        1 kg flour
    }
    inputs {
        2 kg wheat
    }
}

Assess the process bake.

Once again, the assessment engine has inferred the terminal products and substances. The result expresses how much of wheat is required from the technosphere, how much of wood_smoke is released in biosphere, and how much of wood is captured from the biosphere.