Methods
An investment-oriented CGE framework
PIO-CGE description
For the analysis of the economy-wide impacts of investment projects across the different project phases (infrastructure construction, financing and operations) we introduce the Project Investment and Operation single-country CGE model (PIO-CGE). PIO-CGE uses the IFPRI standard model \cite{robinson2002} as a starting point and thus inherits its main characteristics suitable for analyses in developing contexts: the capability to assess impacts over multiple household types (urban/rural, income groups) and to include labour by skill level; the inclusion of home (non-marketed) and subsistence consumption; the small open-economy assumption - trade is permitted subject to duties but does not influence world prices of commodities.
Other more general characteristics of CGE are also inherently adopted: utility maximising households, cost minimising firms, supply and demand parity across all commodity and factor markets. Trade is included through commodity flows between the economy (Ghana) and the rest of the world: following the Armington assumption \cite{Armington_1969}, imports and domestic varieties are considered imperfect substitutes; exports are supplied through a CET function (constant elasticity of transformation) through which domestic production needs to adapt to foreign markets.
Productive activities are specified through nested CES functions (constant elasticity of substitution). To allow for a more advanced specification of the role of energy within an economy, the IFPRI specification of production was extended to include direct substitution possibilities between capital-labour and energy, similarly to other energy-oriented models (e.g. \cite{2002}, other ENV-LINKAGES, GREEN) - Figure \ref{802454}. Energy bundle