PV


 * PV Estimation Utility http://sunbird.jrc.it/pvgis/apps/pvest.php
 * C21e solar electric roof tiles or slates, work with concrete tiles http://www.solarcentury.co.uk/Your-home/Re-roof-C21e-Solar-tiles-slates
 * PV tiles that work with clay rather than concrete tiles http://www.imerys-roof-tiles.co.uk/united_kingdom/