TurboCharge your Solar ROI with an EV

What immediately becomes clear is that EV fuel replacement triples your solar ROI (Return On Investment).

Dollar Flow

Power Flow

See the Analytics page for a view of realtime Power Flow compared to $$ Flow.

Assigning a dollar value to each measured component of the power flow is the first step. It's pretty straight forward really. Essentially the power contract (as convoluted as it is) establishes an export price and an import price. However, using solar power to charge the car battery pits the price of petrol against the price of electricity from the grid.

The turbo kicks in when the Zappi charger diverts as much of the solar generated power as possible in to the car. In fact it becomes free (but not free as in free free) to operate with the replacement energy value becoming the price of petrol. So how much is that?

The graph reveals all. The replacement value fluctuates up and down as various home appliances come on and off. Whenever it becomes quiet the Zappi starts feeding the car. Boom, all of a sudden the savings skyrocket.

The technicalities

Adding per sample $ values to the analytics indices via Kibana enables a seemless realtime bill viewing. The process, known as rating ( what is rating ), converts power measurements to $$.

Here at ElectricBrain raw powerflow data is decomposed and a price added to each sensor's measurement on a per minute basis. In the world of data analytics this is known as data enrichment. In this case that process is particularly easy as the associated costs are pretty much fixed (except for petrol).

The basis for comparing electricity prices to petrol prices relies on the Mitsubishi PHEV which measures both. While these numbers fluctuate with driving conditions, the comparison settled on was 8.6 litres/100km which translates to 18kWh/100km. Depending on fuel types and prices (the PHEV here runs on 98 RON seeing as so little is ever purchased) which, allowing for other lower cost fuel types, translates to a number something like $0.70/kWh. Anywhere between $0.60 and $0.80 depending on where you are located and your electricity prices will effect the graph.

It's pretty certain, however, that the grid won't be paying anything like fuel prices for your solar system's exports.