The question every electric car buyer asks is how convenient charging will be, and how much will the range limit my travel - known as "range anxiety."

I have written often about the new economies in transportation that future technology like robocars provide. In my research I've learned something that seems to not be well known in the transportation world -- that often, smaller is better and more energy efficient.

As you might guess, my recent switch to an electric car is revealing a variety of things to me, so you will be seeing more on that in the coming period.

Here's a moderately surprising result of switching to an electric car. Here in California, my electric bill went down. Just by a little, but in essence the (green) energy for my car is coming for free.

On my recent bill I used 900kwh and paid $168. 2 months ago I used 700kwh and paid $178. I drove around 900 miles. A small amount of my car electricity came from Tesla superchargers or other charging stations. Most was from my house. Yes, I use an above average amount of electricity already.

Why this this happen?

As an update to my proposal for a special circuit breaker to assist in managing home power I thought I would propose a much simpler alternative for those who have a dryer plug in their garage.

As I posted earlier I purchased a Tesla Model 3, the mid-range version with one motor and autopilot.

There are many reviews of this car out there, so I will go quickly over the common issues to get to areas I can give a special perspective on.

Scooters from Lime and Bird have been causing a stir as they move quickly into cities. There's been blowback, because riders travel recklessly, often on sidewalks, and they also leave scooters just lying on the sidewalk, blocking things, because as dockless scooters you can drop them anywhere. Riders are also getting hurt, these are not the safest things to ride.

So cities are striking back, trying to stop, regulate or collect money from these scooter operators.

Some news items, and then some analysis of the energy needed to reposition and charge all the dockless scooters from Lime and Bird.

While I was watching a rocket lifting some of my friend's satellites into space from my driveway yesterday, my new electric Tesla car was delivered to that driveway.

In the world of electric cars, some people talk about an idea called "vehicle to grid" or V2G. Renewable energy's biggest challenge is storage -- wind and solar only come at certain times of the day, but we need electricity all day. The V2G hope is to use all the batteries in electric cars as a means of grid storage.

Many of us believe that there's a natural fit between electric drive trains and robocars. It's not required -- you can certainly make robocars driven by gasoline, natural gas, hydrogen or anything else.

Electric has several advantages:

I and many others feel the best way to set urban and transportation policy is to properly price in the "externalities" into our travel, and to remove all other penalties and subsidies. If you can do this, then everybody is incentivized to improve the public good. In particular, entrepreneurs and companies are motivated this way, and it's their job to think of the new things nobody else thought of.

Today I want to look at some implications of Tesla's Master Plan Part Deux which caused some buzz this week. (There was other news of course, including the AUVSI/TRB meeting which I attended and will report on shortly, forecast dates from Volvo, BMW and others, hints from Baidu, Faraday Future and Apple, and more.)

In Musk's blog post he lays out these elements of Tesla's plan

• Integrating generation and storage (with SolarCity and the PowerWall and your car.)
• Expand into trucks and minibuses
• More autonomy in Tesla cars
• Hiring out your Tesla as a robotaxi when not using it

Except for the first one, all of these are ideas I have covered extensively here. It is good to see an automaker start work in these directions. As such while I will mostly agree with what Tesla is saying, there are a few issues to discuss.

Electric (self-driving) minibus and Trucks

In my article earlier this year on the future of transit I laid out why transit should mostly be done with smaller (van sized) vehicles, taking ad-hoc trips on dynamic paths, rather than the big-vehicle, fixed-route, fixed-schedule approach taken today. The automation is what makes this happen (especially when you add the ability of single person robocars to do first and last miles.) Making the bus electric can make it greener, though making it run full almost all the time is far more important for that.

The same is true for trucks, but both trucks and buses have huge power needs which presents problems for having them be electric. Electric's biggest problem here is the long recharge time, which puts your valuable asset out of service. For trucks, the big win of having a robotruck is that it can drive 24 hours/day, you don't want to take that away by making it electric. This means you want to look into things like battery swap, or perhaps more simply tractor swap. In that case, a truck would pull in to a charging station and disconnect from its trailer, and another tractor that just recharged would grab on and keep it going.

I've been electric car shopping, but one thing has stood out as a big concern. Many electric cars are depreciating fast, and it may get even faster. I think part of this is due to the fact that electric cars are a bit more like electronics devices than they are cars. Electric cars will see major innovation in the next few years, as well as a decline in their price/performance of their batteries. This spells doom for their value. It's akin to cell phones -- your 2 year old cell phone still functions perfectly, but you dispose of it for a new one because of the pace of innovation.

Last week, I commented on the VW scandal and asked the question we have all wondered, "what the hell were they thinking?" Elements of an answer are starting to arise, and they are very believable and teach us interesting lessons, if true. That's because things like this are rarely fully to blame on a small group of very evil people, but are more often the result of a broad situation that pushed ordinary (but unethical) people well over the ethical line. This we must understand because frankly, it can happen to almost anybody.

The ingredients, in this model are:

1. A hard driving culture of expected high performance, and doing what others thought was difficult or impossible.
2. Promising the company you will deliver a hotly needed product in that culture.
3. Realizing too late that you can't deliver it.
4. Panic, leading to cheating as the only solution in which you survive (at least for a while.)

There's no question that VW has a culture like that. Many successful companies do, some even attribute their excellence to it. Here's a quote from the 90s from VW's leader at the time, talking about his desire for a hot new car line, and what would happen if his team told him that they could not delivery it:

"Then I will tell them they are all fired and I will bring in a new team," Piech, the grandson of Ferdinand Porsche, founder of both Porsche and Volkswagen, declared forcefully. "And if they tell me they can't do it, I will fire them, too."

Now we add a few more interesting ingredients, special to this case:

• European emissions standards and tests are terrible, and allowed diesel to grow very strong in Europe, and strong for VW in particular
• VW wanted to duplicate that success in the USA, which has much stronger emissions standards and tests

The team is asked to develop an engine that can deliver power and fuel economy for the US and other markets, and do it while meeting the emissions standards. The team (or its leader) says "yes," instead of saying, "That's really, really hard."

They get to work, and as has happened many times in many companies, they keep saying they are on track. Plans are made. Tons of new car models will depend on this engine. Massive marketing and production plans are made. Billions are bet.

And then it unravels

Not too many months before ship date, it is reported, the team working on the engine -- it is not yet known precisely who -- finally comes to a realization. They can't deliver. They certainly can't deliver on time, possibly they can actually never deliver for the price budget they have been given.

Now we see the situation in which ordinary people might be pushed over the line. If they don't deliver, the company has few choices. They might be able to put in a much more expensive engine, with all the cost such a switch would entail, and price their cars much more than they hoped, delivering them late. They could cancel all the many car models which were depending on this engine, costing billions. They could release a wimpy car that won't sell very well. In either of these cases, they are all fired, and their careers in the industry are probably over.

Or they can cheat and hope they won't get caught. They can be the heroes who delivered the magic engine, and get bonuses and rewards. 95% they don't get caught, and even if they are caught, it's worse, but not in their minds a lot worse than what they are facing. So they pretend they built the magic engine, and program it to fake that on the tests.

We know electric cars are getting better and likely to get popular even when driven by humans. Tesla, at its core, is a battery technology company as much as it's a car company, and it is sometimes joked that the $85,000 Telsa with a $40,000 battery is like buying a battery with a car wrapped around it. (It's also said that it's a computer with a car wrapped around it, but that's a better description of a robocar.) (Update: Since this article was written, the cost of the Tesla battery has dropped to closer to $20,000.)

There has been lots of buzz over announcements from Tesla that they will sell a battery for home electricity storage manufactured in the "gigafactory" they are building to make electric car batteries. It is suggested that 1/3 of the capacity of the factory might go to grid storage batteries.

This is very interesting because, at present, battery grid storage is not generally economical. The problem is the cost of the batteries. While batteries can be as much as 90% efficient, they wear out the more you use and recharge them. Batteries vary a lot in how many cycles they will deliver, and this varies according to how you use the battery (ie. do you drain it all the way, or use only the middle of the range, etc.) If your battery will deliver 1,000 cycles using 60% of its range (from 20% to 80%) and costs $400/kwh, then you will get 600kwh over the lifetime of a kwh unit, or 66 cents per kwh (presuming no residual value.) That's not an economical cost for energy anywhere, except perhaps off-grid. (You also lose a cent or two from losses in the system.) If you can get down to 9 cents/kwh, plus 1 cent for losses, you get parity with the typical grid. However, this is modified by some important caveats:

• If you have a grid with very different prices during the day, you can charge your batteries at the night price and use them during the daytime peak. You might pay 7 cents at night and avoid 21 cent prices in the day, so a battery cost of 14 cents/kwh is break-even.
• You get a backup power system for times when the grid is off. How valuable that is varies on who you are. For many it's worth several hundred dollars. (But not too many as you can get a generator as backup and most people don't.)
• Because battery prices are dropping fast, a battery pack today will lose value quickly, even before it physically degrades. And yes, in spite of what you might imagine in terms of "who cares, as long as it's working," that matters.

The magic number that is not well understood about batteries is the lifetime watt-hours in the battery per dollar. Lots of analysis will tell you things about the instantaneous capacity in kwh, notably important numbers like energy density (in kwh/kg or kwh/litre) and cost (in dollars/kwh) but for grid storage, the energy density is almost entirely unimportant, the cost for single cycle capacity is much less important and the lifetime watt-hours is the one you want to know. For any battery there will be an "optimal" duty cycle which maximizes the lifetime wh. (For example, taking it down to 20% and then back up to 80% is a popular duty cycle.)

The lifetime watt hour number is:

Number of cycles before replacement * watt-hours in optimum cycle

The $/lifetime-wh is:

(Battery cost + interest on cost over lifetime - battery recycle value) / lifetime-wh

(You must also consider these numbers around the system, because in addition to a battery pack, you need chargers, inverters and grid-tie equipment, though they may last longer than a battery pack.)

I find it odd that this very important number is not widely discussed or published. One reason is that it's not as important for electric cars and consumer electronic goods.

Electric car batteries

In electric cars, it's difficult because you have to run the car to match the driver's demands. Some days the driver only goes 10 miles and barely discharges before plugging in. Other days they want to run the car all the way down to almost empty. Because of this each battery will respond differently. Taxis, especially Robotaxis, can do their driving to match an optimum cycle, and this number is important for them.

A lot of factors affect your choice of electric car battery. For a car, you want everything, and in fact must just do trade-offs.

• Cost per kwh of capacity -- this is your range, and electric car buyers care a great deal about that
• Low weight (high energy density) is essential, extra weight decreases performance and range
• Modest size is important, you don't want to fill your cargo space with batteries
• Ability to use the full capacity from time to time without damaging the battery's life much is important, or you don't really have the range you paid for and you carry its weight for nothing.
• High discharge is important for acceleration
• Fast charge is important as DC fast-charging stations arise. It must be easy to make the cells take charge and not burst.
• Ability to work in all temperatures is a must. Many batteries lose a lot of capacity in the cold.
• Safety if hit by a truck is a factor, or even safety just sitting there.
• Long lifetime, and lifetime-wh affect when you must replace the battery or junk the car

Weight is really important in the electric car because as you add weight, you reduce the efficiency and performance of the car. Double the battery and you don't double the range because you added that weight, and you also make the car slower. After a while, it becomes much less useful to add range, and the heavier your battery is, the sooner that comes.

That's why Tesla makes lithium ion battery based cars. These batteries are light, but more expensive than the heavier batteries. Today they cost around $500/kwh of capacity (all-in) but that cost is forecast to drop, perhaps to $200/kwh by 2020. That initial pack in the Tesla costs $40,000, but they will sell you a replacement for 8 years down the road for just $12,000 because, in part, they plan to pay a lot less in 8 years.