The building is using solar energy as a source of electricity production with photovoltaic stepping toward the south side. 
http://www.cseindia.org/userfiles/Ar%20Deependra%20Prashad_DPAP.pdf

References

https://inhabitat.com/finlands-luukku-house-wins-architecture-prize-at-solar-decathlon/
http://www.nzeb.in/case-studies/detailed-case-studies-2/ipb-case-study/