With 21 LEDs with the lightsaver version 0.6b it draws 250 uA current that would be 100 days of service off a 9 volt battery. So the simple fact is regular lighting for less than a watt per day is here. With a 0.0026 watt draw it is very possible that a whole building of lights would run off a driveway LED for all day providing full energy needs of the lighting. This is a real thing that can be done with 6-7 volt 80 mA solar cell you can run 30 lights of 200 – 500 lumen of light so all buildings of the World were to adopt this light it would be the same as removing all the cars off the road in energy savings
Version 0.6b of driver where I have a 7 series X 5 wide LED matrix. No Earth ground is connected to the circuit. with no 6.8 – 560 pf cap used and a 10000uf 25 volt on other with about a 3-5 M ohm resistor. T1 is 30 ga. bifilar wound clockwise single layer over AM loopstick with 24 ga. bifilar wound clockwise both are top to bottom. To set the load take a breadboard and connect in series about 10 – 15 LEDs conect one end and go about 5 -7 LEDs and test for current it will drop when you have the direction and the proper load attached. Remember it is a big balancing act to get the load verses removal of the stored EMF verses having to overcome the stored power by removing it thus lowering the operating cost ( energy ).