Productivity Growth and Biased Technological Change in Hydroelectric Generating Dams

This paper analyses productivity growth and the nature of techni- cal change in a sample of Portuguese hydroelectric generating plants over the period 2001 to 2004. In a ¯rst step, we employ the Luen- berger productivity indicator to estimate and decompose productivity change. The results paint a picture of mixed productivity performance in the Portuguese energy sector. In a second step, we analyse the na- ture of this technical change by using the recent concept of parallel neutrality (Briec et al., 2006). We observe a global shift in the best practice frontier as well as evidence of input bias in technical change.