feat(impact): document types of impact

source/carbon/configuration.rst

@@ -55,7 +55,7 @@ All assets
 
 1. To calculate the emission of greenhouse gas related to energy consumed during use of your assets, the plugin needs to know when an asset is used for the first time and when its services is stopped.
 
-To do so, the plugin seearches for the following dates on order of decreasing precedence:
+To do so, the plugin searches for the following dates on order of decreasing precedence:
 
 * **startup date** (Financial and administrative informations) : **this information is mandatory**
 * **delivery date** (Financial and administrative informations)
@@ -69,7 +69,7 @@ To do so, the plugin seearches for the following dates on order of decreasing pr
 
 .. note:: Monitors rely on the location of the computer it is connected to, so there is no need to add it manually
 
-2. The plugin needs to know where is an asset to determine which carbon intensity is applied to its energy consumption. The associated location mist have the field **Country** filled
+2. The plugin needs to know where is an asset to determine which carbon intensity is applied to its energy consumption. The associated location must have the field **Country** filled
 
 3. Each asset must be associated with a model so that the plugin can estimate CO2 emissions as closely as possible. This information can be pre-filled from a `template <https://glpi-user-documentation.readthedocs.io/fr/latest/modules/overview/templates.html>`_
 

source/carbon/index.rst

@@ -14,3 +14,5 @@ Carbon is a plugin which helps you to monitor environmental footprint of your as
    carbon_reports
    limitations
    recommendations
+   types_of_impact
+   methodology

source/carbon/methodology.rst

@@ -0,0 +1,29 @@
+Methodology
+===========
+
+Embodied impacts
+----------------
+
+Depending on the enabled engine, the methodology of embodied impact may vary.
+
+
+Boaviztapi
+^^^^^^^^^^
+
+Boaviztapi is a tool produced by Boavizta, an association helping organizations to assess, manage and reduce the environmental impact of their digital assets in a simple, fast and reliable way.
+
+The Carbon plugin sends queries to this tool to get metrics which are locally saved and agregated.
+
+Usage impacts
+----------------
+
+The plugin internally calculates the emissions of C0_2Eq, using the carbon intensity of the local electricity supplier of each asset. Other impacts are calculated by external tools.
+
+Greenhouse gas emissions
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+The Carbon plugin identifies the location of an asset, the average power consumption and theoretical power-on and power-off times to approximate the amount of greenhouse gas emitted by the asset's usage.
+
+The carbon intensity of electricity is collected from local providers and down-sampled to 1 hour time slots. For each asset where there is enough data, the plugin evaluates when it is powered on and calculates the average energy consumed then the carbon emissions of this energy consumption.
+
+The results are then aggregated by day, and are used to calculate the total carbon emission on a larger time frame, like a month or a year.

source/carbon/types_of_impact.rst

@@ -0,0 +1,21 @@
+Types of impact
+===============
+
+Carbon dioxide equivalent
+--------------------------
+
+The amount of carbon dioxide (CO2) emissions that would have an equivalent effect on a specified key measure of climate change, over a specified time horizon, as an emitted amount of greenhouse gas (GHG) or a mixture of other GHGs. For a mix of GHGs, it is obtained by summing the CO2-equivalent emissions of each gas. There are various ways and time horizons to compute such equivalent emissions (see greenhouse gas emission metric). CO2-equivalent emissions are commonly used to compare emissions of different GHGs, but should not be taken to imply that these emissions have an equivalent effect across all key measures of climate change.
+
+Climate change 2021, IPCC, glossary, page 2224
+https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_FullReport.pdf
+
+Antimony equivalent
+--------------------
+
+Antimony is a metalloid: it has properties of both metals and non-metals. It is used in life cycle assessments to assess the impact of tie extraction from the Earth crust of non-biotic resources, like minerals and fossil fuels.
+
+
+Primary energy
+--------------
+
+The primary energy is the energy contained in natural resources before any conversion or transformation. It is used in lifecycle assessments to assess the impact of energy extraction from the Earth.