Policy instruments on electricity production from renewable sources. The variable measures the presence of a policy instrument in 1970, 1980, 1990, and 2000.

Variable coding:
0 = 'No policy'
1 = 'Obligatory standard, prohibition or ban'
2 = 'Technological prescription'
3 = 'Tax or levy'
4 = 'Subsidy or tax reduction'
5 = 'Liability scheme(s)'
6 = 'Planning instrument'
7 = 'Public investment'
8 = 'Data collection / monitoring programme(s)'
9 = 'Information based instrument'
10 = 'Voluntary instrument'
11 = ‘Extra instrument for energy’.