1. Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC.
2. The German government's Energy Concept, Long/term strategy for future energy supply. 28.09.2010. From http://www.bmu.de/english/energy_efficiency/doc/46516.php.
3. California Renewable Energy Ressources Act. From http://www.leginfo.ca.gov/pub/11-12/bill/sen/sb_0001-0050/sbx1_2_bill_20110412_chaptered.html, April 2011.
4. Roadmaps - Smart Grids © OECD/International Energy Agency 2011, figure 1, page 2.
5. Ogimoto K.; Power System Evolution - System wide issues related to massive penetration of PV in the electricity systems. IEA Task 14 meeting Valencia September 2010.