For example they may obstruct fish migration and affect populations. For example, carbon dioxide (CO2) emissions in Austria -measured in kilograms per USD of gross domestic product (GDP), purchasing power parity (PPP) adjusted - were 0.1 kg per PPP USD of GDP in 2014. In Albania, Bosnia and Herzegovina, the Former Yugoslav Republic of Macedonia, Montenegro and Serbia the respective C02 emissions were 0.2, 0.6, 0.3, 0.2 and 0.4 kg per PPP USD of GDP (World Bank, n.d ). There is considerable scope to increase both the security of supply and the sustainability of the energy sector by diversifying fuel sources. However, installed capacity of these technologies is practically non-existent at present (see Table 12.1). Renewables are promoted through a range of policy initiatives including rules for grid connection of renewable generation, obligations for the purchase of renewable power specified in secondary legislation such as grid codes and rule books, and subsidies to generation from renewables.