An Editorial Article: A Marriage of Convenience – Electric Vehicles and Solar Energy

By: Anthony Cotton, Energy Conscious, LLC, Connecting the Dots…

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Solar has been gaining ground at an accelerating pace. Electric Vehicles (EV’s) are poised to do the same. Utilities and other change adverse entities are starting to push back hard.

One significant battlefront is net metering… a mechanism where the grid acts as a balancing agent for intermittent Solar production.


Although in the past the grid was for many considered the source of power, the grid also acts as a very important balancing agent. This balancing operates across a number of time scales;

  • immediate (minutes)… balancing thousands of devices switching on and off
  • daily (hours)… balancing typical peaks in morning and evening with very low loads late at night
  • seasonal (months)… balancing seasonal shifts between winter heating load transitioning to summer air-conditioning (AC) load

Now the grid has to balance both variable loads AND variable sources. They have a very real and legitimate concern.

We all need to be “good grid citizens”… but how?

Solar (Photovoltaic PV) Limitation


Market penetration for unmanaged solar is” guesstimated” to be about 15% due to the grid instability impacts of intermittent production. Sun is out= full production,  clouds appear = full production can drop off significantly. This is not an issue when Solar installations are few and far between.  But what if they start to take off, like in mature markets such as California and Hawaii?

If only there was a way to economically buffer this free intermittent resource.

Electric Vehicle (EV) Limitation


Electric Vehicle adoption is currently minimal, but signs of material growth are on the near term horizon (i.e., Tesla’s recent 400,000 sight unseen orders for the Model 3). Some utilities have a program where they will pay you $50 to “register” your new EV with them. They are watching for a situation known as “clustering”… multiple neighbors getting EVs in quick succession. That can represent a significant new load in one specific location.

Moving this charging load to the quiet early morning hours can help significantly. But as adoption levels increase there may be a point where a capacity upgrade (transformers or residential lines to support them) is needed… but then the question is . . .  who will pay?

If only there was a way to adopt this much cleaner mode of transport without costly facilities upgrades.

A Systems Approach…”A Marriage of Convenience”

Photovoltaic (PV) and Electric Vehicles (EV) not only need each other… they were made for each other. Only together, can they move past their individual market penetration limits.


  1. PV growth needs a way to buffer the intermittency of local production…. but it can’t add expense without value (i.e., it cannot negatively impact its current ROI)
  2. EV growth needs a way to support substantial increasing loads without materially impacting the existing distribution network.

It is generally accepted that local storage is the answer to item #1 above. The closer to the source of production, the better.

Some have made the connection that distributed production (local) can address item #2. Again, the closer the source of PV production is to the EV load, the better.

But here is something that is not generally recognized:

“Re-purposed” EV packs (i.e. after they have achieved their ROI in the vehicle, they are now candidates for hanging on a wall in your garage (a.k.a Tesla Powerwall). They are now fully recovered (economically) resources serving a second and substantial economic life in buffering Solar AND storing local production to charge the EV rather than having to pull that load thru the distribution network… a Marriage of Convenience!


Looking forward we see PV and EV tightly coupled both physically and economically.

PV is locally deployed along with EV’s and their second life packs now hanging on the garage wall. The re-purposed packs are buffering the intermittent solar and load shifting the daily peaks to the later night time loads (primarily recharging the EV for the next day’s travel). This stable and predictable load profile, paves the way for unlimited PV adoption moving forward.

At the same time, people start to recognize the significantly stronger value proposition of PV offsetting $2.50-$3.00/gal gasoline rather than $0.15/kWh electricity.

The final piece is the intelligent power electronics needed to orchestrate all these major new power flows in the home. The emerging IoT (Internet of Things) promises to organize these new power producers and consumers into autonomous and resilient “Enernet” nodes.

Clean energy AND grid stability will grow in from the edges by entrepreneurial entities with the vision to “…connect the dots”.

Note: Since this article was drafted, there have been several significant announcements establishing re-purposed EV packs as a target for supporting growing levels of intermittent renewables.

Link 1 – Nissan and Eaton introduce home energy storage system with second-life EV batteries

Link 2 – “We believe electric vehicles can become a mobile power unit,”