Both the grow-out farms (see Table 2) and the feed-mills
used electricity. We modelled electricity production and
supply by adapting the Norwegian production and distribution
network in EcoInvent®2.0 to the Vietnamese
situation. Norway was used because it most resembled
Vietnam in terms of its shape, energy source distribution
and electricity supply grid. The energy sources used for
electricity production (hydro-powered 20%; diesel 50%;
gas 12%; coal 18%) were retrieved from the Vietnam
Energy Information Administration (Anon 2007). We
assumed that all electricity imported from neighbouring
countries originated from hydro-powered plants. Moreover,
we assumed that natural gas remained equally important
after start-up of the new power plant in Ca Mau (An 2009)
and that diesel remained important for the other existing or
new plants in the Mekong Delta. On-farm electricity use
varied from close to 1 to 108 kWh/t fish; the average of
41 kWh/t fish was used in the calculations.