Do Electric Vehicles Reduce Power Grid Capacity?

Bruce Murdoch, Cranbrook, BC, discusses the misinformation that abounds about BC's electricity capacity and the impact Electric Vehicles (EVs) have on the power grid.

Electric Vehicle (EV) charging

How EVs Can Boost Power Grid

This sounds counter-intuitive right? It sure does! I am going to demonstrate how EVs can (and already do to a small extent) free up capacity on the grid and electrical generation capacity. We are facing a lot of fearmongering about power utilities running out of capacity, and this is just one of many strategies that will expose the disinformation coming from fossil fuel companies and climate deniers.

How Power Capacity is Determined

When a utility such as BC Hydro determines the need for power generation capacity, they calculate the power requirements for the highest demand of the year. The rest of the year, there is plenty of capacity due to lower demand. So they get set up for the worst day of the year, and the worst time of that day…….usually it is a day in January between 4pm and 9pm when it is dark and cold, and everyone is getting home from work. So let’s say they can reduce those peak loads by 10%. Suddenly, they have 10% more power capacity and don’t have to spend nearly $20 billion each on more new Site C dams.

How EVs Fix the Capacity Problem—–V2G

V2G means Vehicle-to-Grid. That requires a charger that can send electrons in two directions: into the vehicle from the grid, or back into the grid from the vehicle. Since the power utility company has massive overcapacity in the middle of the night when everyone is sleeping, the EV gets fully charged. Then, it discharges that power back into the grid at peak times, ie 4-9pm, effectively borrowing night capacity and shifting into daytime capacity. Alternatively, you can simply power your house off the car during the day/early evening).

Electric Vehicle EV charging profits and savings

Why Would EV Owners Do This?

Because it makes money for them. BC Hydro already has a Time of Use power rate system. If you draw power at night, from 11pm to 7am, they charge you about 6cents/kWh vs the normal day rate of 11cents/kWh. With this system, they charge 16cents/kWh from 4-9pm. So the EV users charge up at night for 6cents, and discharge during the day to avoid 11-16cents daytime costs. For most homes, 4-9pm is about 20% of their full day’s use.

For EV owners who are home most of the time, that means their electricity costs can be nearly 100% at 6cents, which is super cheap. For EV owners who drive to work, their day would look like this: charge to 100% between 11pm and 7pm, and if they get home at 5 pm, they discharge from 5pm to 11pm. On weekends, it can discharge all day when the car is not being used.

Is This Really a Big Deal?

Yes, it will be. There are 200,000 EVs in BC right now, and that number is expected to grow faster as prices come down. So I did some calculations (thanks to AI) to find out how many cars it would require to feed the grid and free up capacity on the grid by 10% during peak hours. I assumed each car would have 50kWh of capacity to share. Here are the calculations.

"To calculate how many EVs with 50 kWh capacity would be needed to power 10% of British Columbia’s electricity demand from 4-9 pm (a 5-hour period), the steps are:

1. Total average daily electricity use in BC: 180 GWh.

   
   

2. 10% of daily electricity use: 180×0.10=18180×0.10=18 GWh.

   
   

3. The 4-9 pm (5 hour) period is 524≈0.208245≈0.208 of the day.

   
   

4. Assuming demand during this peak period is 1.5 times the average to reflect higher load: 18 GWh×1.5×0.208=5.616 GWh18 GWh×1.5×0.208=5.616 GWh

   
   

5. Each EV’s battery capacity is 50 kWh = 0.05 MWh.

   
   

6. Number of EVs needed: 5,616 MWh0.05 MWh/EV=112,320 EVs0.05 MWh/EV5,616 MWh=112,320 EVs

   
   

Therefore, it would require about 112,320 electric vehicles with 50 kWh capacity each, fully discharged, to supply 10% of BC’s electricity demand during the 4-9 pm peak period.

This calculation assumes ideal conditions including full battery discharge and vehicle-to-grid capability, which may not be fully achievable in practice but indicates the scale of storage represented by EVs [calculation based on previous data].” (calculations by Perplexity Pro AI)

So it is already theoretically feasible to free up 10% of the grid’s capacity with only 112,320 cars needed for the requirements.

Here is where the numbers get really interesting. To increase BC Hydro’s capacity by 10%, it would cost $20 billion based on the cost of the Site C dam. How many EVs could you buy for $20 billion at $50,000 each? 400,000. But of course they don’t have to buy the vehicles, they are are already bought and paid for by EV owners who simply need to be paid to use their vehicles during peak hours.

How Close is This To Becoming a Reality?

California already has numerous pilot projects currently underway. Once they learn best practices from that, V2E will roll out and the rest of the world can learn from them. California V2G should be widely available before 2030. (V2X -Vehicle-to-Everything)

In the meantime, Time of Use rates are already shifting electrical loads into the night time with EV charging, laundry and dishwashers drawing at night. Even hot water can be maximized at night and turned off during the day if the tank is big enough.

The entrenched fossil fuel interests who are hard at work trying to scare people away from electrifying are counting on people not being aware of what is coming to allow full electrification that we need to clean up the atmosphere.

Bruce Murdoch, Cranbrook BC