This technology needs to evolve with more intensity as it's one of the most useful for solving the problem of pollution. If a construction has solar panels, there's the possibility of storing all the unused energy for later use and ensuring that all is utilized with intelligence.
The most obvious factors are solar energy and batteries, although the circuit that provides charge also plays a very important role. Solar energy seems more or less constant and leaving aside the efficiency of photovoltaic cells, the great challenge is then the methodology of storage and time of self discharge.
For instance Ni-MH (Nickel – Metal Hydride) batteries were evolving to create a new technology called “Low Self Discharge” as the common ones do have a high rate of self discharge up to 30% per month. The self discharge rate, one of the most relevant specifications, it's sometimes not specified as it should perhaps because the numbers aren't especially wonderful.
Another specification of maximum value appears in the number of recharging cycles and original capacity after a threshold.
Thinking in a dwelling, these specifications need to be even better. There's hope to solar panels lasting more than a millennium or batteries retaining 100% capacity after unlimited cycles. Nonetheless nothing is perfect and the present environmental state claims for a shift toward renewable energies.
30-40 years for a solar panel is not bad, or 20 for a battery pack. These numbers are now a reality thus the technology is ready for being implemented as a rule in any dwelling.