Caught this story by the Financial Times and was shocked at the lengths the “reporter” went misinform the public. To be fair, perhaps Peter Campbell and Nathalie Thomas are just that ignorant, but if that is the case, they should not be reporting on stories like this.
Problems started with the headline:
Tesla truck will need energy of 4,000 homes to recharge, says study
Wow, the energy of 4,000 homes to power a single truck? That is staggering. Or is it? The key data point missing from the headline is the time factor. Energy for 4,000 homes for how long? Well, quick back of the envelope math tells me that assuming they were talking about the long range truck, which has a 1,000 kWh battery, we are at 250 watt-hours per home. So, how long will 250 wH last in a U.K. home? That depends on how much the home consumes. According to the Office of Gas & Electricity Markets, The average U.K. home consumes between 1,900-7,100 kWh per year. If I take the median value of those numbers, I get 4,500 kWh, or 12.3 kWh per day, or roughly 513 wH per hour. Based on those assumptions, we are running our 4,000 homes for less than 30 minutes.
Now, the energy to run 4,000 homes for just less than a half hour is an impressive amount of energy, but now we have context to our numbers, something the original headline did not convey. If I chose, I could have used the same absence of time context to make the headline “scarier” by using the lowest value of electrical consumption from OFGEM, run them for only a second, and then written:
Tesla truck will need energy of 15.9 million homes to recharge, says study
Way scarier headline, and just as true as the first one.
Okay, off to a bad start. Let’s go with the first three paragraphs:
One of Europe’s leading energy consultancies has estimated that Tesla’s electric haulage truck will require the same energy as up to 4,000 homes to recharge, calculations that raise questions over the project’s viability.
The US electric carmaker unveiled a battery-powered truck earlier this month, promising haulage drivers they could add 400 miles of charge in as little as 30 minutes using a new “megacharger” to be made by the company.
John Feddersen, chief executive of Aurora Energy Research, a consultancy set up in 2013 by a group of Oxford university professors, said the power required for the megacharger to fill a battery in that amount of time would be 1,600 kilowatts.
Here some context is implied, if we assume 30 minutes is the time the are talking about our 4,000 houses running, and we use that median consumption value of 4,500 kWh per year. But the article doesn’t tell us this, violating the first rule of math: “show your work”.
We are then introduced to this John Feddersen chap and his four year old consulting company made up of some Oxford professors. We are not told who Aurora Energy Research is funded by, their purpose, or the academic disciplines of these professors. When I popped over to AER’s web site I found that they are, in fact a consulting firm, with 15 directors, whose academic expertise consisted of eight economists, three business admins, one mathematician, one philosophy/French major and one mechanical engineer. What was completely lacking from a consulting firm that specializes in the entire spectrum of energy generation would be anyone with actual engineering expertise in any of the relevant fields. How much weight do I give Mr. Feddersen’s opinion on the technical aspects of Tesla’s batteries, chargers, and drive trains when he is an economist. not an electrical, chemical or materials engineer?
Tesla declined to comment on the calculations.
Well, one can understand why Tesla will not take time out of its busy schedule to rebut the opinions of people lacking the expertise to understand the rebuttal.
Mr Feddersen used the example of the Tesla truck to highlight the need for greater debate around how grid infrastructure will need to be adapted to meet demand for electric vehicles.
“There are smart and dumb ways to incorporate this level of capacity requirement into the system, but either way, fully electrified road transport will need a large amount of new infrastructure,” he told the Financial Times.
Certainly true. Also true: There are smart and dumb ways to write an article about this subject, but either way you need competent reporters talking to actual experts in relevant fields in order to write them.
National Grid, which oversees Britain’s electricity system, has suggested that in the most extreme scenario, electric vehicles could create as much as 18 gigawatts of additional demand for power at peak times in the UK by 2050.
Right, so what are the other scenarios? The more realistic ones that are not “the most extreme”? In the most extreme scenario I can foresee, a previously undetected asteroid the size of the moon could slam into the Earth in the morning and annihilate all human life on the planet. However, should I plan my breakfast cereal purchase according to that scenario, or a more reasonable one that involves being around to eat my Fruit Loops™?
Industry experts believe strains on the system could be reduced by using “smart chargers” that only re-boot vehicle batteries when the grid is able to cope, rather than at peak times, such as after work.
One “recharges” vehicle batteries, one does not “re-boot” them. And that, boys and girls, says all we need to know about the “expertise” of this article.