Dr. Ahmed G. Abo-Khalil

Electrical Engineering Department

Energy payback

Energy payback

The energy payback time of a power generating system is the time required to generate as much energy as was consumed during production of the system. In 2000 the energy payback time of PV systems was estimated as 8 to 11 years[64] and in 2006 this was estimated to be 1.5 to 3.5 years for crystalline silicon PV systems[60] and 1-1.5 years for thin film technologies (S. Europe).[60]

Another economic measure, closely related to the energy payback time, is the energy returned on energy invested (EROEI) or energy return on investment (EROI),[65] which is the ratio of electricity generated divided by the energy required to build and maintain the equipment. (This is not the same as the economic return on investment (ROI), which varies according to local energy prices, subsidies available and metering techniques.) With lifetimes of at least 30 years[citation needed], the EROEI of PV systems are in the range of 10 to 30, thus generating enough energy over their lifetimes to reproduce themselves many times (6-31 reproductions) depending on what type of material, balance of system (BOS), and the geographic location of the system.[66]

Office Hours

Monday 10 -2

Tuesday 10-12

Thursday 11-1

My Timetable


email: [email protected]

[email protected]

Phone: 2570


Welcome To Faculty of Engineering

Almajmaah University




Links of Interest





Travel Web Sites






ستقام اختبارات الميدتيرم يوم الثلاثاء 26-6-1440

حسب الجدول المعلن بلوحات الاعلان

Summer training

The registration for summer training will start from 5th week of second semester

Academic advising

Class registration week 1

إحصائية الموقع

عدد الصفحات: 2879

البحوث والمحاضرات: 1280

الزيارات: 60411