Q1 2015: $3.09/Wdc total for $0.70/Wdc modules [1]
Q1 2016: $2.93/Wdc total for $0.63/Wdc modules [2]
Q1 2017: $2.80/Wdc total for $0.35/Wdc modules [3]
Conclusion: Even if the modules cost $0.0000001, the total price could not fall much more unless the rest of the business model gets updated. Probably some solar installer companies will drop out of the market, and the survivors will adapt to lower profits.
The raw costs, not adjusted for inflation:
Q1 2014: $4.52/W total for $1.03/W modules [0]
Q1 2015: $3.09/Wdc total for $0.70/Wdc modules [1]
Q1 2016: $2.93/Wdc total for $0.63/Wdc modules [2]
Q1 2017: $2.80/Wdc total for $0.35/Wdc modules [3]
Conclusion: Even if the modules cost $0.0000001, the total price could not fall much more unless the rest of the business model gets updated. Probably some solar installer companies will drop out of the market, and the survivors will adapt to lower profits.
[0] Page 12, https://www.nrel.gov/docs/fy14osti/60401.pdf
[1] 5.2kW system. See page 7, https://www.nrel.gov/docs/fy15osti/64746.pdf
[2] 5.6kW system. See page 16, https://www.nrel.gov/docs/fy16osti/66532.pdf
[3] 5.7kW system. See page 21, https://www.nrel.gov/docs/fy17osti/68925.pdf