Tesla to offer Zero Marginal Cost Motoring

We've all witnessed first-hand how within just two decades the internet has digitised industry after industry to deliver an increasingly zero marginal cost society (Marginal cost is the cost of producing an additional unit of a good or service after fixed costs have been absorbed.)

While I don't subscribe to the entire zero marginal cost society thesis, it is a good explanation for the effects that have transformed information industries like media, music & software. The same now applies increasingly to energy. While the fixed costs of the harvesting technologies to generate green electricity are decreasing exponentially, the marginal cost of producing renewable energy is near zero. The sun and the wind are free and only need to be captured and stored.

At a recent shareholder meeting, Elon Musk said Tesla's new solar shingles will cost less than a "normal roof" and the energy would essentially be free. Does this mark the dawn of mass market zero marginal cost mobility? Popular Mechanics recently ran the experiment, powering three electric vehicles with a conventional rooftop PV system. They concluded that buying a rooftop PV system to power your electric vehicle is comparable to prepaying three years worth of gasoline, based on $4/gallon, and never having to pay for it again.

We think the payback time for a retrofitted rooftop PV system can be even shorter! Based on average annual motoring of 15,000 km/year, a small 1.5 kW PV array (Popular Mechanics used 7.5 kw) could power a typical EV like a Nissan Leaf (114 Wh/km quoted energy consumption) on it's daily commute for 25+ years at an average cost of < $0.004/km.

Eliminating the $240/month a typical household spends on vehicle fuel, a modest rooftop PV system would pay for itself in just 6 months. Ticking the box to have Tesla tiles fitted to your new house eliminates the payback stage altogether. It is effectively a rooftop perpetual fuel pump where the per kilometer cost is zero from day 1.

Combine Tesla's solar shingles and EV powertrain which, irrespective of their "infinite Mile" 8 year warranty, is expected to last well in-excess of a million miles, (true for all EVs) with the ever growing installed base of rooftop PV systems (25% of households in some Australian states) and we could soon see zero marginal cost mobility becoming reality at internet speed, hammering another couple dozen nails in the coffin of ICE cars.

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