written 13 Mar 2022
published 20 Mar 2022
The price of oil and gasoline has jumped in the last few weeks due to the Russian invasion of the Ukraine, highlighting that the supply of oil was already barely able to satisfy global demand. Since global oil production peaked a few years ago, this will continue to get worse with time. In addition, global scientists, the Federal government, and the State of California are all calling for a 50 percent reduction in atmospheric carbon emissions by 2030, if we are to have any chance of a habitable climate for our grandchildren. Reducing fossil fuel demand by increasing energy efficiency, and rapidly shifting our energy economy, is now more essential than ever. Last week, in part 1, I described what will be needed to achieve this goal, in terms of increased renewable production and storage. But that is just a start.
Transportation produces about half our carbon emissions, and there are over 90,000 vehicles in Mendocino county. EVs are 3 times more energy efficient than internal combustion engines, reducing emissions and overall energy demand, but will require an extensive charging system. The basic questions are: what to install, how many to install, and where to place them.
What to install?
Most of the EVs on the market today consume about 30KWhr (kilowatt hours) for each 100 miles of travel, and battery capacities for a 250 to 300 mile range are becoming common. Every year we see more models, with increased affordability and longer range.
There are three levels of chargers. Level 1 is generally 120V(volts)@15A(amps) (1.8KW/hr), which can be plugged into any household outlet. Level 2 is 240V@30-80A (7.2KW/hr-19.2KW/hr). Most of the public chargers are level 2, which can also be installed in a home. Levels 1 and 2 charge through an EV standard plug rated at 80 amps.
Level 3 is 400-900V@100-400A (40KW/hr-360KW/hr), requiring significant electrical infrastructure, costing 6 to 10 times more to install than a level 2 charger because they handle so much more power, and therefore are usually only public. Level 3 chargers use a different plug, and the industry standard has not yet been determined.
Most level 2 chargers already installed have current capacities averaging 34A (8KW/hr), which is the typical battery charging rate for EVs today, giving about 25 miles of range for each hour of charge. But charging rates will increase rapidly as EV production matures. Since EV chargers are a long-term investment, it seems prudent to install only 80A level 2 chargers, providing the maximum current rating of the standard plug. This will support the newer vehicles as they become available, providing 100 miles of range from a 90 minute charge, without any further upgrades.
How many to install?
The State of California suggests a ratio of one public charger for every 20 vehicles. To cut transportation emissions in half by 2030, 45,000 vehicles in Mendocino county will have to shift to electric, requiring 2300 public chargers.
Where to place them?
Assuming most EV owners will charge at home, the demand for public chargers divides into six categories: transient charging, tourist overnight charging, fleet charging, shopping/socializing charging, work charging, and those with no home charging available.
Transient charging, supporting long distance travel, is the only situation justifying the more expensive level 3 chargers, providing several hundred miles of further range in a fraction of an hour, and should be located primarily along the 101 corridor.
Tourists who come to the county and spend the night should be able to charge at their hotel or motel. As fleets transition to EVs, overnight charging will be needed, and the same sites could be used to supply workers or customers during the day. The last three categories are county residents who need to recharge to return home. Any business where people are likely to spend an hour or more, or where workers park, should plan to have significant parking lot charging. The downtown shopping areas of each city should have extensive charging opportunities.
Places where vehicles are parked should not only have access to charging, but also canopy arrays to collect and store the power, reducing the load on the grid, while maximizing the use of the land.
Developing such charging infrastructure by 2030 will require coordination between the local utilities, governments at all levels, local businesses, and private financing.
