Tables A.1 and A.2 show that crude oil makes a big contribution
to the total WFES, even though it contributes very little to
the WFEP. This is because Thailand imports most of its crude oil
and thus depends on water in foreign countries. On the other
hand, it is the exact opposite for petroleum products: they
contribute heavily to the WFEP but very little to the WFES. This
indicates that Thailand consumes water to produce petroleum
products for exportation to foreign countries. In addition, it is
inferred that some of the imported crude oil is used to produce
petroleum products for exportation. Therefore, a next step in
developing a more accurate estimate of the WFEP and WFEP
would be to include foreign trade and intermediate transactions
by energy commodities