ecoinvent Forum Archive

Hello,

I need a bit of help understanding data sources for US grid electricity. I will use "market for electricity, high voltage/WECC, US only" from ecoinvent v3.6 as an example.

In the General Comment section, we can read:

* This dataset describes the electricity [...] for year 2014. 

* The shares of electricity technologies on this market are valid for the year 2016.

Then, in the Time period, we have a start period of 2014 and an end of 2019, with a comment indicating data is for 2014. 

Then, in the extrapolation section, we can read "This dataset has been extrapolated from year 2017 to the year of the calculation (2019). The uncertainty has been adjusted accordingly."

And, to add to the confusion, we have a "last edit date" of 2015-07-29.

I hoped to consult the documents mentioned in this comment "Further information can be found in a report available on ecoQuery, section 'Files'.", but could not find them.

CAn anyone clarify exactly what is being modelled in this dataset?

Thanks!

I received a direct answer from Christopher Oberschlep of PSI who worked on the dataset. He states that “The "market for electricity, high voltage [WECC, US only]" is a 2016 mix of unit-level US-WECC generation data with added disaggregated electricity imports from CA and MX. Thus, it is not a "complete" consumption mix as electricity trade between NERC regions is missing due to lack of data. While the general approach in this form therefore stayed the same compared to earlier ecoinvent versions, we have changed to a more detailed data source that allowed to abolish some of the simplifying assumptions from before (mostly with regards to technology splits). As a consequence, some US electricity markets have changed substantially in their composition, but US-WECC is not one of them.”

Ecoinvent, am wrong in assuming that the references to earlier years (2014) are vestiges of previous versions of the dataset, and that the reference to a future year (2017) is a mistake?

Dear Pascal,

Thank you for your comment. Indeed you are correct, that the reference to the year 2014 in the general comment is remnant of the comment in the undefined dataset, which remained unchanged since its creation. We acknowledge that this is confusing. The reference to 2017 and other timestamps you mention have different meanings:

In the General comment: ‘This dataset describes the electricity available on the high voltage level in Western Electricity Coordinating Council, US part only for year 2014. This is done by showing the transmission of 1kWh electricity at high voltage.’ This comment remains from the original dataset which was created for 2014. The section following this comment indicates for which year the statistics on which the shares and production volumes are based on are valid. Nevertheless, the electricity markets get regularly updated (yearly). Check the approach we use to update the electricity markets here. The empty market in the unlinked version gets updated with new shares and production volumes and the general comment is appended.

The start and end of period indicate during which years the dataset is considered valid. For the linked dataset the ‘End of period’ is set to the year of the publication of the selected ecoinvent version (e.g. 2020 for 3.7.1). This is also why the comment in ‘Extrapolations’ is added, which states that the dataset has been extrapolated from the ‘End of Period’ registered in the undefined dataset (which in this case is 2017) to the year of calculation (2020).

The field ‘Last Edit Date’ refers to the date when the undefined version of this dataset was edited the last time.

I hope this clears things up for you and I apologise for any confusion. When looking at electricity markets please refer to the second part of the general comment to gather on which year and statistics the shares and production volumes are based

Best regards,

Johannes Müller, Data Analyst, ecoinvent association

Thank you Johannes for the clarifications.

Pascal