【正文】 abour in underdeveloped economies cast serious doubts on any substitution possibilities. Given such supply constraints, capitallabour substitution bees inevitable. Furthermore, if the nature of technologies employed are considered, the fact that these are largely intermediate technologies that are energy intensive highlights the energy intensity of their use in production activities. Thus, it is not just the doubtful substitution possibility between labour and capital that is the 7 problem here, but rather that the energy implication of the absence of such a possibility demands some attention. It is this fact that underlines the plementarity between energy and capital and the attendant implications for energy consumption intensity in developing countries. Also critical to the debate is the cost associated with substituting capital for energy which has not received adequate consideration in the debate. In order to enhance capitalenergy substitution possibilities, massive investment in plants and equipment is necessary to replace the energy intensive intermediate technology widely in use. There is also an additional cost associated with developing the human re source base that is necessary to maximize the envisaged energy savings that would accrue from the introduction of efficient technologies (Cecelski et al, 1979). If such transition costs were to prove prohibitive, developing countries economies would be exposed to serious energy constraints. Equally important are the zero substitution possibilities that exist between mercial and traditional energy with respect to certain industrial and household activities, partly because of supply constraints, but mainly due to cooking habits and traditions. In other areas where these possibilities exist, the environmental costs in terms of desertification and drought tend to cast serious doubts on its sustainability as a longterm energy strategy. Evidently, it is obvious from the latter point that the issue of plementarity and substitutability between energy and capital in developing countries is largely irrelevant. Instead, we would argue that for the developing countries, energy plements capital. Given the desire of developing countries to increase valueadded contributions to primary modity exports on the one hand, and on the other, the small substitution possibilities between capital and labour, capital and foreign exchange scarcities will bine to plicate energy scenarios in these countries (Dunkerley et al, 1981). Several studies undertaken for the developing countries have indicated strong relationships between energy and economic growth (Leach et al, 1986。s industrial sector contributes 43% of total GDP, Tanzania contributes only 5%. Generally though, the sector in both countries exhibits similar characteristics, being dominated by import substituting footloose assembly type industries. Consequently, few backward or forward linkages exist between the industrial sector and the rest of the economy. A perennial balance of payment deficit, brought about largely by modity price fluctuation and adverse terms of trade between primary modities exports and manufactured imports, is a mon feature of both economies. Increasingly, external borrowings and financial aid have 9 bee dominant in macroeconomic planning. Consequently, these countries have bee heavily indebted. For example, total debts for 1992 stood at US$30 998 million and US$6715 million for Nigeria and Tanzania respect ively (World Bank, 1994). The magnitude of the impact on economic growth has caused unease at the Economic Commission of Africa, given the increasing proportion of export proceeds devoted to debt servicing (ECA, 1988). For example, total external debts to exports were % and % for Nigeria and Tanzania respectively in 1992. Furthermore, external debt as a proportion of GNP in 1992 was % and % respectively for the two countries (World Bank, 1994). It is no coincidence that economic growth has varied with foreign exchange availability in these countries (Singh, 1986). The energy sectors of both economies are undeveloped and characterized by shortages and supply constraints (Ebohon, 1992). While Nigeria is a oil exporter and flares more than 90% of its gas reserve, energy shortage is so marked that power interruptions and fuel shortages are monplace (Ebohon, 1992). This is attributable to inadequate energy infrastructure, lack of spare parts, manpower shortage and inefficient management. In Tanzania, it is rather the inability to sustain the huge energy import bills that is largely responsible for energy supply related debt, as a proportion of Tanzania39。 an increase in energy consumption) cannot be rejected for Tanzania in view of the estimated standard errors. This means that the inclusion of past values of Yand E in the regressions provided a better explanation of current values of E and Y than when excluded. Indeed, by this method, a simultaneous causal relationship can be seen to exist between energy consumption and economic activities, proxied by GDP and GNP. Given the predominance of cash crops and agricultural exports in total economic activities, this es as no surprise. However, a priori observation may suggest low energy use。s energy structure casts huge doubts on its ability to achieve sustainable economic growth and development, given its energy problems. Despite its huge mercial energy reserve (hydroelectricity, crude oil, gas and coal), percapitaenergy consumption ranked among the lowest in the world. Conventional or biomass energy (mainly wood and charcoal) account for more than 70% of total energy consumption whereas in Asia and Latin America, this source accounts for only 35% and 25% respectively (Davidson, 1992). While rural energy demand is totally met from this source, only 10% of ur