Disclosed herein are various embodiments of systems for drilling and operating a well which may have dual uses. The well may be drilled and operated as a geothermal well using a hybrid approach where a heat transfer fluid is injected into a hot rock formation but is not removed, and heat is extracted using a closed loop method. The geothermal well is then evaluated for use as a carbon dioxide sequestration well. In other embodiments, the well is drilled as a carbon dioxide sequestration well and then evaluated for its potential for generating geothermal energy using a hybrid approach where supercritical carbon dioxide is injected into a hot rock formation but is not removed, and heat is extracted using a closed loop method. Both horizontal and vertical wells are disclosed, in sedimentary rocks and in basement granite.