Clarification on the unit and meaning of Capital investment demand by tech (1975$ vs billion 1975$)

[yeonjungin11-bok]

Hi GCAM team,

When running the query “Capital investment demand by tech” in the model interface, the unit is displayed as 1975$.
However, it’s unclear whether this refers to absolute 1975 dollars or billion 1975 dollars.

From reviewing the source code (e.g., technology.cpp, input_capital.cpp), it appears that the variable may represent total capital investment (in 1975$) after multiplying by output.
Still, the accompanying note seems to imply billion 1975$, and when comparing the results with energy-investment from the National Accounts (reported in million 1990$), the magnitudes differ substantially.
So I’d like to better understand what Capital investment demand by tech exactly represents in economic terms compared with energy-investment.

Could anyone please clarify:

1.What is the correct unit of Capital investment demand by tech (1975$, million 1975$, or billion 1975$)?

2.Conceptually, how should this output be interpreted relative to energy-investment in the National Accounts?

Thanks in advance for your help!