There have been some mentions of using a Tesla for fleet use, but I don’t recall seeing any workup on it, please forgive me if I am repeating. (No this is not a parody this time, so if you see some smelly assumptions call me out on it :smile: )
I was talking to an uncle-in-law who is a police officer in a smallish Texas town. He gave me some basic facts that started my analysis engine going:
Range is less of a concern than I would have imagined. The gas guzzlers they are using (Dodge chargers) get 19mpg and have 19.1 gallon tanks. Only 362 miles of range!
So the driving conditions are:
Here I am looking at an existing Model S, in terms of cost and capability. I think it could be an 85 nonP (although I suspect the “performance” is 15k upgrade that is 95% profit for Tesla, perhaps they can throw that in for free). So excluding fancy paint and pano roof figure a “model P” at about 90k to be conservative. Ideally, the car would be tweaked a bit. The styling could be toned down a bit, to raise up the roof in the back seat. Also, the back should really have a regular trunk instead of a hatchback purely because that is pretty lousy security for transporting suspects. But I suppose some bars in back of the seat would serve.
First I looked at range to see how unpleasant it would be. The EV suffers from not being able to refill between shifts, but the model is still decent. Here I am assuming the force is using HPWC with twin chargers:
So while the second shift can quickly top off the ICE, an EV officer would be starting with 2/3 range. But, with just a small amount of flexibility that can be fixed. For instance, if they plugged in for as little as one hour during a shift change (which seems likely/easy anyway) you get this:
Which is practically the same. In fact, since the officers actually DRIVE to the fuel depot you can see that much of that 1 hour turnaround time is absorbed by the ICE trip TO the fuel, whereas the EV could charge at the station.
Verdict: No real range concerns relative to a gas guzzler police cruiser.
So then I went to model the cost. A police force might be paying a premium to get a “Model P” fleet, but maybe it’s worth it? I laid out my analysis a few different ways to check it and found a surprising result. With the use parameters the way I understand it, a “Model P” fleet saves money from year 1. Here are my assumptions used:
I worked backwards from the “mostly idle” and “much less than 100 miles/shift” to get these parameters. So 2/3 idle time to get that low mileage. I am also boldly assuming a x2 lifetime due to many fewer moving parts, but I looked at x1 lifetime as well. Finally I assumed a 1kW/hour “idle” usage for EV car plus police gear. If someone knows the idle draw of a Model S I can fill in with some estimates for actual police kits. 1kW seems generous to me though, given that police lights are LED now and a typical laptop takes 100W going full bore. I then assume an ICE maintenance cost of $5k/year and EV cost of $1k/year. This excludes the cost of tires which is a function of miles and doesn’t change.
A look at the first 4 years:
Or looking long term (20 years) for a fleet of 20 cars, see graph below. Here I am assuming that the force replaces 4 cars a year. After 5 years they are over the 200k and are retired. So at 4 cars per year, this force never stops buying new cars, but if the EV lasts twice as long, they stop buying cars for 5 years. (The “1x” case below buys 4 EV’s a year just like the ICE’s with no extra lifetime assumed).
That is a 13 million dollar advantage from the ICE baseline to my 2x case, and this is a small police force. Astonishingly going to an EV fleet saves money from year 1. I figured most of the savings would come from my 2x lifetime advantage, but actually even x1 works. The difference in fuel costs is more dominant. The MOST dominant parameter is the more efficient idling performance. An ICE uses about 1 gallon per hour idling ($3.50 of fuel) or a kWh of idling ($0.10 of fuel). Even if I am off by a factor of 3x that is a huge efficiency.
Verdict: EV costs far cheaper relative to a gas guzzler police cruiser.
Tactical Advantages of an EV:
Let’s not forget, these are Tesla’s we are talking about. So the police could outrun just about everything on the road, and maneuver like a beast. (The Dodge charger goes 0-60 in 5.1 seconds) We brag about the performance of the Model S to our friends, but the police are the people who could actually put it to work. Also, they are *quiet*. That has to be worth something to police. But to me the intriguing possibility about the “model P” Is the big 17” touchscreen. This is of marginal value to the consumer, but for police (and taxis) this would be a GODSEND. If you have seen the inside of a police car, it is basically a bunch of computer terminals perched awkwardly in front of the center stack. As far as I know, the principle use of that computer gear is for dispatch information and crime database access. With some (not insignificant) software dev, that could simply be integrated to the Model P computer and be another app they can switch to, leaving room for other gear and greatly cleaning up the interior (and taking thousands of dollars of equipment cost out of the car, although some has to go back to the SW developer since their unit volume would be low for a long time).
Conclusion:
Because of the way police use their vehicles, (high annual mileage, long idle times, and predictable patterns), and due to the fact that police tend to have vehicles that are large with powerful engines, switching to EV’s is especially cost effective. Certainly by the time the Gen III comes out, the advantages will be even more apparent. To the extent that EV’s make sense for the typical commuter, they make vastly more economic sense to someone operating vehicles for long hours and high daily mileage like police forces.
I was talking to an uncle-in-law who is a police officer in a smallish Texas town. He gave me some basic facts that started my analysis engine going:
- Cost of a sedan (Dodge Charger) ~20k (plus the cost of the equipment, computers, lights etc. I am not modeling that cost because it’s the same for any car).
- Cars do 2 10 hour shifts and “rest” for a 10 hour shift in a 30 hour cycle.
- A 10-hour shift would always be much less than 100 miles, even for a patrol car which surprised me. Generally they don’t just drive around, they are driving from call to call, and if no call is coming in, they idle and do paperwork.
- Most of the gas used was idle time. When police are filing reports, using the computers, working a car accident, or just about anything else, the car is idling, since the lights and electronics would drain the battery quickly.
- They fill the tank at the beginning of every 10 hour shift. So the cars are very topped off all the time. They buy directly in bulk so there is no retail markup, but retail markup for gas is quite small.
- The cars are retired from patrolling at 100k, and demoted to some other purpose to 200k and then auctioned. The second 100k is for detectives and such.
Range is less of a concern than I would have imagined. The gas guzzlers they are using (Dodge chargers) get 19mpg and have 19.1 gallon tanks. Only 362 miles of range!
So the driving conditions are:
- low average speed, stop and go city driving with a lot of “stop”.
- Hours of idle time.
- Little highway time.
- A lot of electronic use onboard.
- Need to have extra capacity ready all the time (running out of gas while following someone or transporting a suspect is really not an option).
Here I am looking at an existing Model S, in terms of cost and capability. I think it could be an 85 nonP (although I suspect the “performance” is 15k upgrade that is 95% profit for Tesla, perhaps they can throw that in for free). So excluding fancy paint and pano roof figure a “model P” at about 90k to be conservative. Ideally, the car would be tweaked a bit. The styling could be toned down a bit, to raise up the roof in the back seat. Also, the back should really have a regular trunk instead of a hatchback purely because that is pretty lousy security for transporting suspects. But I suppose some bars in back of the seat would serve.
First I looked at range to see how unpleasant it would be. The EV suffers from not being able to refill between shifts, but the model is still decent. Here I am assuming the force is using HPWC with twin chargers:
So while the second shift can quickly top off the ICE, an EV officer would be starting with 2/3 range. But, with just a small amount of flexibility that can be fixed. For instance, if they plugged in for as little as one hour during a shift change (which seems likely/easy anyway) you get this:
Which is practically the same. In fact, since the officers actually DRIVE to the fuel depot you can see that much of that 1 hour turnaround time is absorbed by the ICE trip TO the fuel, whereas the EV could charge at the station.
Verdict: No real range concerns relative to a gas guzzler police cruiser.
So then I went to model the cost. A police force might be paying a premium to get a “Model P” fleet, but maybe it’s worth it? I laid out my analysis a few different ways to check it and found a surprising result. With the use parameters the way I understand it, a “Model P” fleet saves money from year 1. Here are my assumptions used:
I worked backwards from the “mostly idle” and “much less than 100 miles/shift” to get these parameters. So 2/3 idle time to get that low mileage. I am also boldly assuming a x2 lifetime due to many fewer moving parts, but I looked at x1 lifetime as well. Finally I assumed a 1kW/hour “idle” usage for EV car plus police gear. If someone knows the idle draw of a Model S I can fill in with some estimates for actual police kits. 1kW seems generous to me though, given that police lights are LED now and a typical laptop takes 100W going full bore. I then assume an ICE maintenance cost of $5k/year and EV cost of $1k/year. This excludes the cost of tires which is a function of miles and doesn’t change.
A look at the first 4 years:
Or looking long term (20 years) for a fleet of 20 cars, see graph below. Here I am assuming that the force replaces 4 cars a year. After 5 years they are over the 200k and are retired. So at 4 cars per year, this force never stops buying new cars, but if the EV lasts twice as long, they stop buying cars for 5 years. (The “1x” case below buys 4 EV’s a year just like the ICE’s with no extra lifetime assumed).
That is a 13 million dollar advantage from the ICE baseline to my 2x case, and this is a small police force. Astonishingly going to an EV fleet saves money from year 1. I figured most of the savings would come from my 2x lifetime advantage, but actually even x1 works. The difference in fuel costs is more dominant. The MOST dominant parameter is the more efficient idling performance. An ICE uses about 1 gallon per hour idling ($3.50 of fuel) or a kWh of idling ($0.10 of fuel). Even if I am off by a factor of 3x that is a huge efficiency.
Verdict: EV costs far cheaper relative to a gas guzzler police cruiser.
Tactical Advantages of an EV:
Let’s not forget, these are Tesla’s we are talking about. So the police could outrun just about everything on the road, and maneuver like a beast. (The Dodge charger goes 0-60 in 5.1 seconds) We brag about the performance of the Model S to our friends, but the police are the people who could actually put it to work. Also, they are *quiet*. That has to be worth something to police. But to me the intriguing possibility about the “model P” Is the big 17” touchscreen. This is of marginal value to the consumer, but for police (and taxis) this would be a GODSEND. If you have seen the inside of a police car, it is basically a bunch of computer terminals perched awkwardly in front of the center stack. As far as I know, the principle use of that computer gear is for dispatch information and crime database access. With some (not insignificant) software dev, that could simply be integrated to the Model P computer and be another app they can switch to, leaving room for other gear and greatly cleaning up the interior (and taking thousands of dollars of equipment cost out of the car, although some has to go back to the SW developer since their unit volume would be low for a long time).
Conclusion:
Because of the way police use their vehicles, (high annual mileage, long idle times, and predictable patterns), and due to the fact that police tend to have vehicles that are large with powerful engines, switching to EV’s is especially cost effective. Certainly by the time the Gen III comes out, the advantages will be even more apparent. To the extent that EV’s make sense for the typical commuter, they make vastly more economic sense to someone operating vehicles for long hours and high daily mileage like police forces.
repair costs would be higher too since I assume replacement aluminum panels would be higher. However, the evidence so far is that Model S do strangely well in accidents. So the relative unlikeliness of being totalled might partially balance out the cost.
