Smart meter- multi tiered power tariff

hi there for those, looking for a solution to smart meter and the multi tier tariff. my friend who lives in another province from me was perturbed because of the new multi tier tariff for smart meter, ~$.018kwh on peak and ~$0.8 offpeak. so here the solution we are trying for him if anyone else wants to try, and seams to work well currently
based on my GTI limiter sketch and emontx shield.
what we did. was calculate his average day time usage ( during the on peak peak time tarrif) in his case it was 500 watt ( not including heat)
500 X 12 = .6 kw.
so we installed 10 150AH- batteries to give him 18 kw of storage. ( could of being smaller but he want extra incase of power outage)
we use the GTI limiter sketch to adjust the current going to the 1kw GTI so that during the peak hours. keeps the grid usage at near zero. then we have a simple timer on the GTI output that disconnects the it from the grid at off peak hours and turns on a charger to maintain the batteries during the night. at a much lower rate of 8cents

currently he does not have any solar panels but next summer he incorporating them into the system. -

our next project this week is to install a heat buffer tank ( I believe that will require about 300 gallons for the size of his house , for this we are installing a couple heating cores, and based on the outside temperature, determines the internal temp of the heat buffer. the colder it is the warm the buffer tank is heated , and the buffer tank is heated only during the off peak hours, basically he operates the opposite of my system as I have lots of heat produce during the day by the sun, his will be heated at night by the electricity… - from my experience chances are he will not even have to duct in into the ventilation system, as one will get enough heat seepage to maintain the internal house temp. but we will in case of a very cold days and to maintain a more accurate living temp .

due in the change of tariff his energy bill went up +$1000 per year. from my guestimates we can recoup about +$1400 as the previously he had a flat rate of about $0.13kwh. as now he will be heating his house at a much lower cost of $0.08kwh compared to before - as heating cost was +60% of his annual bill – if all goes well he should recoup in 2- 3 years
good luck have fun