Will photovoltaics and LEDs compete with usual greenhouses?

What if replace transparent coverings of a greenhouse with non-transparent thermally insulated walls, attach photovoltaics and add LEDs in order to save money on heating. 

Disclaimer: this text may contain mistakes.

I made some calculations for Rotterdam. This city was selected because "The Netherlands has some of the largest greenhouses in the world".

Assuming the temperature inside greenhouse is 30 C, and daily mean outdoor temperature is 10.7 C, the temperature difference is 19.3 K. For cellular polycarbonate (twinwall plastic) U = 3.0 W/(m*m*K). Average heating power is 19.3*3.0 = 57.9 W/m*m or 507 kWh/m*m per year. 507 kWh of natural gas costs some 25$. This value is some reduced due to heating from sun and heat accumulation.

1 square meter of photovoltaics generates 200 W/m*m of electricity, white light LEDs give 200 lumens/watt. It means 40000 lux. The Sun provides up to some 100000 lux, greenhouse coverings has 80% transparency. Plant leaves productivity is limited to 10000 lux, so for most of the plants there will be no difference betwen 40000 lux and 80000 lux.

Assuming photovoltaics costs 0.5 $/W and color LEDs cost the same, 1 square meter costs 200$. Replacing transparent greenhouse coverings with photovoltaics and LEDs will allow to save money on heating that costs 25$/m*m*year. Payback period is 200$/(25$/year) = 8 years. Red-blue lighting might be more effective for vegetation, so payback period might be lower.
Photovoltaics and LEDs are getting cheaper. If it continues, payback period might become 2-3 years in 10 years.

Additionally:
Photovoltaics panels can be optimally oriented or use tracking.
Non-transparent walls prevent escaping of light from inside to outside.
Photovoltaics surface area is not limited to greenhouse coverings area and might be higher.
Battery storage can store excessive energy (excessive light does not increase productivity) and provide it for vegetation during night.
In winter the benefit seems to be higher than year average because daylight is shorter but thermal loses are still happenning 24 hours per day. And heating requirements are higher, and fuel is more expensive, and cucumbers are more expensive.