Limits Of Expertise
Posted by Pete McBreen 15 Feb 2011 at 18:09
A common problem in software development and science is that people are often not aware of the limits of their knowledge.
The electric car provides a great example of this. Richard Muller in Physics for future Presidents makes several statements about the feasibility of electric cars that have turned out to be incorrect.
This quote is from Confusing Future Presidents part 2
High-performance batteries are very expensive and need to be replaced after typically 700 charges. Here is a simple way to calculate the numbers. The computer battery for my laptop (on which I am writing this) stores 60 watt-hours of electric energy. It can be recharged about 700 times. That means it will deliver a total of 42,000 watt-hours, or 42 kilowatt-hours, before it has to be replaced for $130.
Muller implies in this post that a car would need to replace the battery after only 700 cycles, but although this might have been the case at the time, car battery suppliers are continually extending the life of a battery.
Better Place which is the pioneer in rapid change for electric batteries in cars has also pointed out that the end of life is not a fixed point. In their blog post batteries can have a second life they state
In the world of batteries, what does â€œend of lifeâ€ really mean? According to the industry, end of life is defined as that point in time when a battery has lost 20% of its original energy storage capacity or 25% of its peak power capacity. This implies that an EV battery, with an initial range of 100 miles per charge, will reach its end of life when, years later, it only delivers 80 miles per charge.
That time is likely to be reached only after the battery has carried an electric car about 200,000 miles or 2,000 cycles. But that’s not really the end for an EV battery â€“ it’s just the beginning of a second life that not many people know about.
All this goes to show that Muller’s expertise in a branch of physics does not necessarily extend to expertise in economics, engineering and battery chemistry. Muller had tried to dismiss the Tesla roadster before it was released by claiming that it would cost too much and the batteries would be too heavy Confusing Future Presidents part 1. But the Tesla was launched successfully as a niche sports car. Now the GM Volt and Nissan Leaf are also proving that it is possible to build electric cars.
The Better Place business model of renting the battery through quick change stations that can swap a battery faster than you can refuel at a filling station is likely to be a game changer as well.
So the next time someone states categorically that something is not possible, first check to see if they have the relevant expertise in the appropriate areas before listening too long or hard.