# What is the typical embodied energy of a solar photovoltaic panel?

What is the typical embodied energy of a solar photovoltaic panel, in terms of nominal power output or panel area? The ideal answer would be in kWh/WP, but kWh/m2 would also be acceptable.

I understand there is probably a range of answers to this question, so here are some simplifying assumptions:

• If the manufacturing process is more efficient for larger panels, then the answer for large panels (best case scenario) is preferred.
• If the manufacturing process has become more efficient over time, then an answer for the most modern and efficient process (best case scenario) is prefered.
• If different manufacture technologies (monocrystal, polycrystal, thin film) have different amounts of embodied energy, then the lowest answer (best case scenario) is preferred.

According to the Wikipedia article on EROI, 585 kWh/m2 is a median value for the embodied energy of a photovoltaic panel, rated based on surface area.

The "energy invested" critically depends on technology, methodology, and system boundary assumptions, resulting in a range from a maximum of 2000 kWh/m² of module area down to a minimum of 300 kWh/m² with a median value of 585 kWh/m² according to a meta-study. [9]

Assuming a panel efficiency of 20% (typical of commercially available panels) and solar irradiance of 1000 W/m2, 1.0 m2 of panel would have a peak power output (WP) of about 200 W/m2. Or stated differently, it would take about 50 cm2 of panel to deliver 1 Watt, and manufacturing that panel would use about 2.9 kWh of energy.

So as a rough back-of-the-napkin calculation, the embodied energy of a solar panel, normalized for peak power output, is about 2.9 kWh/WP.