Electric Rotary Kiln
- 1.5kg/kWhr at the 70kW scale - . Note: data jump from 50-70kw is dubious here.
- 300kWhr/day from small 50kW array of solar gets us to 450 lb of cement per day - or 2 yards of solar concrete and enough for 1 house a week.
- 24 person operation (50 houses/year) can go solar concrete with a 50kW PV array - rooftop of a 5000 sf workshop.
- Kiln is $15k 
- Modern kilns are 3.5 to 6.5' in diameter 
- Small electric ones are doable, such as this 100 kg/hour modular that fits inside a container.