If one reads enough renewable energy/clean tech blogs, one is led to believe that 'vehicle-to-grid' (V2G) might not be a completely stupid idea. Electric cars are, after all, big batteries! That have energy! Why not use that energy for other purposes?
The latest iteration of this is believing that battery backup from a car during a hurricane might be a good idea. Before addressing the 'emergency scenario', let's discuss the 're-use storage' scenario most often discussed, wherein a Tesla sells power back to the power grid.
The core idea, is that energy storage costs money, and that vehicle-to-grid could save 'billions'.
Of course, there are many primary problems with this:
The latest iteration of this is believing that battery backup from a car during a hurricane might be a good idea. Before addressing the 'emergency scenario', let's discuss the 're-use storage' scenario most often discussed, wherein a Tesla sells power back to the power grid.
The core idea, is that energy storage costs money, and that vehicle-to-grid could save 'billions'.
Of course, there are many primary problems with this:
- The automobile, designed to move, must be idle
- The owner, having bought an electric car with a lot of range, must be willing to sacrifice some anticipated range in order to be paid a dividend for the use of 'surplus' storage
- It assumes companies working on self-driving cars must in some way fail, in order to maintain the current surplus of idle cars
- It assumes electric cars will never be right-sized - electric vehicles will always be big vehicles with fixed batteries
- It assumes pumped hydro storage and other storage alternatives is more expensive than installing the grid network necessary for vehicle-to-grid at scale.
And then the details of each conceived beneficial scenario reveals more issues:
Scenario 1: Give back to the grid during peak times during the workday
- Owner charges car at home
- At work, the car is hooked back up to the grid, after being instructed to keep a reserve for the trip home
- The car sells back the surplus to the grid, owner makes money
The problems:
- The workplace parking lot needs to build out a massive charging infrastructure before this makes sense, (It's no longer sufficient to have a few fast chargers in the garage, the workplace will need to hook up every car in the lot before the utility will see the scale it needs)
- Billing between charging networks, utilities and the customer is now 2-way
- The owner needs to be satisfied in their prediction capabilities (one will not to need to make an extra trip to the grocery store,
Scenario 2: Give back to the grid during peak rate times outside the workday
- Owner charges at work or an otherwise off-peak hour time
- Owner plugs in at home to sell during the late evening, night, or early morning
The problems:
- Rates don't typically work this way
- Owners tend to want to start the day with a maximum range
Scenario 3: Give back to the grid at whatever time the utility needs it
- Owner charges whenever, sets a target charge range
- The automobile charges and discharges as instructed by the utility (responding to pricing)
The problems:
- Resale. Although the owner could allow giving back a large percentage of battery at any time (the owner essentially bought far too much range), the owner pays out of pocket during resale when telling the next potential owner that the battery system was cycling 24/7 to in order to earn a few pennies.
Scenario 4: Give back to home/lights/connectivity during a natural disaster
- There is a natural disaster, like a hurricane
- Owner can hook up car to home
- Home maintains lighting/heat/connectivity
The problem:
It's a fucking natural disaster. Giving up the mobility represented by an electric car is a great example of robbing Peter to pay Paul during the most dangerous circumstances. For a cost likely comparable to the installation of a vehicle-to-home feedback loop, one could simply buy a backup generator or purpose-built backup battery and not deal with the headache of finding one's automobile at 0 miles of range because the "smart home" thought it needed to maintain the living room a few degrees above room temperature and keep the washer and dryer running throughout the storm of the century.
Vehicle-to-grid is stupid, it will not work. People that believe in this nonsense don't understand economics, physics, or psychology.