1. ‘The energy challenge’, (The Stationery Office, London 2006),Department of Trade and Industry
2. ‘Power system reserves and costs with intermittent generation’, UK Energy Research Centre Working Paper, 2006 available at: http://www.ukerc.ac.uk/component/option,com_docman/ task,doc_download/gid,548/, accessed January 2007
3. ‘The cost of generating electricity’, (The Royal Academy of Engineering, London 2004),ISBN 1-903496-11-X), Royal Academy of Engineering and PB Power
4. ‘Planning of the grid integration of wind energy in Germany Onshore and Offshore up to the year 2020’, 2005 available at: http://www.wind-energie.de/fileadmin/dokumente/Themen_A-Z/Netzausbau/ stud_summary-dena_grid.pdf, accessed January 2007 DENA Project Steering Group: Deutsche Energie-Agentur, Berlin