<DIV>For various reasons the development of the energy markets throughout the world has been characterised by market imperfections and government intervention. The energy market has been primarily regarded as a matter of supply, and research has been dominated by technical issues. Since recently the awareness has emerged that this market is determined by demand. In his inaugural speech, Jan Willem Velthuijsen states that government intervention has to be replaced by market elements. Measurement of the determinants of behaviour of energy consumers is of increasing importance to design adequate policy. Plenty of work for economists. <BR><BR><BR>