I’ve had a few interesting articles / news stories cross my path recently related to both energy and transportation. I love optimism, but I don’t have much time for naive optimism. So here are a few bubble-bursting reflections on the future of energy and transportation.
Get your calculators out…
The first article I want to talk about is a very sobering assessment of the state of renewable energy today.
You may have got the impression from announcements like that, and from the obligatory pictures of wind turbines in any BBC story or airport advert about energy, that wind power is making a big contribution to world energy today. You would be wrong. Its contribution is still, after decades — nay centuries — of development, trivial to the point of irrelevance.
And that pretty much summarizes the state of affairs with respect to renewable energy. But, some numbers, please, “…wind and photovoltaic solar are supplying less than 1 per cent of global energy demand.”
That doesn’t sound right. After all, aren’t we regularly told that renewables are providing a greater and greater percent of the energy needs of the world?
Their trick is to hide behind the statement that close to 14 per cent of the world’s energy is renewable, with the implication that this is wind and solar. In fact the vast majority — three quarters — is biomass (mainly wood), and a very large part of that is ‘traditional biomass’; sticks and logs and dung burned by the poor in their homes to cook with.
Ah… the devil is in the details. And here are a few more details for you. The author points out that global energy demand increases roughly 2% per year. Hypothetically, new installs of wind and solar each year could at least cover that, right? Not so easily, it turns out.
At a density of, very roughly, 50 acres per megawatt, typical for wind farms, that many turbines would require a land area greater than the British Isles, including Ireland. Every year. If we kept this up for 50 years, we would have covered every square mile of a land area the size of Russia with wind farms. Remember, this would be just to fulfil the new demand for energy, not to displace the vast existing supply of energy from fossil fuels, which currently supply 80 per cent of global energy needs.
Even if we were to install that many wind turbines people forget that wind turbines are not made of wood, grass and Mother Earth’s kisses. The process of manufacturing wind turbines is highly dependent on fossil fuels, and… um…
But out of sight and out of mind is the dirty pollution generated in Inner Mongolia by the mining of rare-earth metals for the magnets in the turbines. This generates toxic and radioactive waste on an epic scale, which is why the phrase ‘clean energy’ is such a sick joke and ministers should be ashamed every time it passes their lips.
It gets worse. Wind turbines, apart from the fibreglass blades, are made mostly of steel, with concrete bases. They need about 200 times as much material per unit of capacity as a modern combined cycle gas turbine. Steel is made with coal, not just to provide the heat for smelting ore, but to supply the carbon in the alloy. Cement is also often made using coal. The machinery of ‘clean’ renewables is the output of the fossil fuel economy, and largely the coal economy.
They don’t produce a whole lot of power, we need disproportionately large amounts of land just to get what meager power we do get from them, and their environmental impact is plausibly no better than existing technology. In principle I think the continued development of alternative energies is a good thing, but let’s not hold to any naive views about how “clean” this energy really is.
I won’t steal his thunder on the rest of the article, you should really read it yourself.
Fossil fuel vehicles
And then there is this article about the future of fossil-fuel powered vehicles. I always get a chuckle from the profound absurdity of prophets from religious groups like the Jehovah’s Witnesses, but climate catastrophe prophets seem to put them to shame on a regular basis.
No more petrol or diesel cars, buses, or trucks will be sold anywhere in the world within eight years. The entire market for land transport will switch to electrification, leading to a collapse of oil prices and the demise of the petroleum industry as we have known it for a century.
Really. Eight years. Tell me more!
- People will stop driving altogether
- There will be a massive shift to self-driving electric vehicles
- Electric vehicles will be ten times cheaper to run than fossil-fuel vehicles, and will have a 1 million mile life
- Cities will ban human drivers
- Price of oil will plummet
- The fossil-fuel industry will collapse
- Silicon Valley will become the new center for all things vehicular
- Fossil-fuel based vehicles will enter a vicious cycle of increasing costs.
- Etc, etc, etc.
The problem with prophecies of this sort is the rather long list of interconnected chains. If any one of those prophetic chains fails to materialize then the whole chain collapses. For instance, if cities don’t ban human drivers (because, I don’t know, people in democracies might not agree to that; crazy thought…) then the entire picture changes. The predictions are suspect. If the prophecy (elsewhere in the article) that once electric vehicles have a range of at least 200 miles and a sticker price below $20,000 then “the avalanche will sweep all before it.”
For comparison sake, let’s look at the Chevrolet Bolt versus the Chevrolet Sonic. The Bolt is 164 inches long and the Sonic is 160 inches long; very close. Both seat up to 5 passengers. They have the same track width (59 inches) and the legroom and headroom for the passengers are pretty close.
The curb weight for the Bolt is 3,580 lb whereas the Sonic is only 2,784 lb. The Bolt is about 28% heavier for a vehicle that is almost exactly the same size. What gives? It’s the batteries. More later.
And what about range? The Bolt’s range is “estimated” to be about 383 km, or 238 miles. So it meets the one criteria for range. The Sonic (5-door, manual) gets about 9.2 L/100 km on the highway, and it has a 46 L tank, so that translates to a theoretical range of 500 km, or 311 miles; roughly 31% further per fill.
Gasoline tanks take about 5 minutes to refuel, which might get stretched out to, at most, 15 minutes if some of the passengers need to use the facilities, buy another bag of chips, or use the wi-fi. Well, if there’s wi-fi then maybe 30 minutes. So the time it takes to refuel the Sonic is governed in large part by human factors like bladders, appetites and online games.
The Bolt, on the other hand – according to the Chevy website, no less – takes about 9.5 hours for a full charge. Almost ten hours! At a nominal highway speed of 100 km/hr it would take you less than 4 hours to reach your destination, whereas it would take more than twice that time to recharge the battery. In fact, if we take into consideration the recharge time, driving 383 km actually consumes 3.83 + 9.5 hours, for an equivalent of 13.33 hr. This yields an equivalent average speed of 383 km / 13.33 hr = 28 km/hr.
Interestingly, a number very close to that is going to come up again later in this article.
A quick note on price; the Chevy Bolt comes in at $42,000, but there are apparently about $14,000 of government rebates waiting for you. So the equivalent price is about $30K. The Chevy Sonic will run you about $18,000. These are Canadian figures.
The Bolt already surpasses the prophetic milestone of a 200 mile range, so it just needs to get down to $20,000 before the “avalanche” begins. But when it does get to that price, the Sonic is there, waiting for it, as well as other comparable vehicles from other manufacturers. So for the same price I could buy a vehicle with an average highway speed of about 100 kph or one with an average highway speed of about 28 kph, once you factor in the outlandish recharging time. And I can go about 30% further with the first one.
Electric cars probably make a lot of sense for city driving, but the moment you travel anywhere outside the city it’s going to be a long time before electric vehicles are a serious contender. Perhaps that’s why the Chevy Bolt sales figures are around 1,000 units per month in the US, whereas the Sonic’s sales figures got as high as 12,799 per month in August of 2014. Most months are at least 5,000 per month.
There’s no article for this one, but I have to cover it because it’s a personal interest of mine. Every now and then the idea of electric powered flight comes up and I always roll my eyes. Let me explain why.
Let’s take a pretty “average” airplane, the Cessna 172. According to Wikipedia it has an empty weight of 1,691 lb, a gross weight of 2,450 lb, a fuel capacity of 56 US gallons and a range of about 801 miles. The engine is rated to 160 Hp. Wing area is 174 ft2.
[Please excuse me for mixing imperial and metric units; I’m Canadian, but the aviation world is very much still imperial based. At least here in Canada it still is.]
Now let me introduce you to something called “energy density” (for the non-engineers in the crowd). There are multiple ways of measuring it, but for this article I’ll use weight. Energy density is the measure of how much energy something can contain per weight. For instance, aviation fuel (commonly called AvGas) has an energy density of about 45 MJ/kg. That’s 45 MegaJoules (1,000 Joules) per kilogram of fuel. How much is a MegaJoule? That doesn’t actually matter for this article, but your natural gas bill probably presents your monthly usage in GigaJoule (GJ) which is 1,000 times more than MJ, if you need a little context.
By comparison, Tesla’s model 3 is expected to have 30% greater energy density than (as I understand the article) the PowerPack 2; that means 30% greater than 130 Wh/kg. So what’s a Wh? Wh – or Watt * Hour – is just another way of measuring MJ; kind of like kilometer versus mile. From onlineconversion.com we find that 130 Wh is 0.468 MJ.
Or, 130 WH/kg is 0.468 MJ/kg. AvGas was about 45 MJ/kg, or about 100 X greater energy density than the Tesla battery pack. And the Tesla is likely one of the best battery packs out there for these kind of applications.
So what does that mean, practically speaking? If my Cessna 172 requires a certain amount of energy to fly me to some destination 801 miles away, then I can either get that energy from the AvGas or from a battery. But if I use a battery instead, then the weight of the battery will have to be about 100X the weight of the AvGas in order to provide the same amount of energy.
[This is part of the reason why electric vehicles have such lousy ranges; they’ve already packed a whole bunch of heavy batteries in there, but the energy they get from all that weight just doesn’t compete with fossil-fuels.]
So how much weight are we really talking about? I mentioned before that the Cessna 172 can carry about 56 US gallons of fuel; how much does that weigh? AvGas weighs about 6 lb / US Gallon, so that’s a total of 56 x 6 = 336 lb. If we were to get the same amount of energy out of batteries we would need about 100X that weight of batteries, or about 33,600 lb of batteries.
But you’ll recall that the Cessna’s maximum weight is only 2,450 lb, which means, to get the same performance out of batteries you would need more battery weight than 13 fully-loaded Cessna 172’s somehow magically squeezed into a single Cessna 172.
Just for fun, let’s consider solar panels; why not just mount solar panels on the upper surface of an airplane’s wing and get a bunch of free energy from the sun? First of all, have fun the moment a cloud passes…
The average sunlight hitting the earth over a 24 hour period of time is 164 Watts per m2. 164 Watts is about 0.22 HP. So to get the full 160 HP that the Cessna 172 requires would mean that we need about 160 / 0.22 = 727 m2 of solar panels. That’s about 7,825 ft2, or about 45X as large as the wing area of the Cessna 172 (which was 174 ft2). If we needed about 13 fully-loaded Cessna 172’s worth of batteries in one Cessna 172, then we need about 45 Cessna 172’s worth of wings, packed with solar panels, in order to get as much power as we need to run it.
And that assumes we convert 100% of incoming solar energy into electricity, so these numbers don’t even take into account the dismal efficiency of solar panels; less than 50%. And the more efficient solar panels are far more expensive; your typical commercially available solar panel might be in the range of 10% efficient.
We will have flying cars much sooner than we have electric airplanes. And they will probably be gasoline powered.
High efficiency cars
This article peaked my curiosity. Students at various universities have designed and built cars to test how efficient we can, theoretically, travel with various energy sources. The winning team this year built a car that can theoretically go 2,713 miles on a single gallon of gasoline.
Before you get all excited, read the fine print. First, let’s just say this vehicles isn’t exactly a five-seater like the Bolt, and there is very little – or, more to the point, absolutely nothing – for trunk space. It’s a purely R&D type of vehicle; not something you might actually drive in the real world.
Ah, but surely we can apply some of the technology to the real world. Yes, of course, there will probably be some applicable technological discoveries, but considering the overall design of the vehicle I suspect the applicable technology will be very limited. For instance, the engine is a mere 2 Hp. Yes, that’s right, 2.0 whole horsepower. The test takes place on a closed test track which, I’m going to hazard a guess, doesn’t have any big hills. Furthermore, the test involved getting the vehicle up to speed, killing the engine, and coasting for as long as possible until starting the engine again. The teams only had to sustain an average speed of 15 mph.
Again, good luck driving that slowly on the TransCanada highway.
15 mph, by the way, is approximately 24 kph. Which, if you’ll recall, is only marginally slower than the Chevy Bolt’s average speed (including refueling time) of 28 kph.
The bicycle alternative
The previous article begins by asking you to, “Imagine making the 2,710-mile trip from Philadelphia to Los Angeles using just one gallon of gas.” The test vehicle from Laval University can average about 24 kph so the trip would take quite a long time.
The Chevy Bolt can average 28 kph, once you account for the recharging time, but at least you get to bring your friends along. And a little bit of luggage (mind you, it’s no minivan).
But what about biking; how does that compare? With a bit of physical training – well, ok, with a whole lot of physical training, a support team, and probably a pretty expensive bicycle – it compares very well. The world record for Ultra Marathon, for men, is held by Christoph Strasser who biked 3,020 miles at an average speed of 26.425 kph back in 2014. That’s even further than from Philadelphia to Los Angeles.
26 kilometers per hour.
A high-end R&D gasoline powered vehicle using only 1 gallon of fuel, a commercially available passenger electric vehicle that spends more time recharging than driving, and an Ultra Marathon biker would all take about the same amount of time to get across the continental United States. Which is to say, more than a week.
Or, you could make the same trip in about two days worth of driving and spend the other five days of your time relaxing when you wanted to, where you wanted to, and for how long you wanted to. Are electric vehicles going to sweep everything else away? Colour me skeptical.
I’m a big advocate of advancing technology and seeking alternatives to non-renewable energy sources. I seriously am. In fact, I biked to work on the day this article published; about 40 km round trip.
But let’s not delude ourselves into thinking that we are on the cusp of some great technological revolution that is going to overthrow fossil-fuels any time in the next… oh, I don’t know… generation or two. Maybe three or four generations. Fossil-fuels are going to be here for a very long time because the physics surrounding the alternatives just don’t serve humanity nearly as well. They are far too limited right now. We must support their continued advancement, while acknowledging they have a very long way to go.
And considering the ungodly amount of government funding and private investment that is being thrown at these technologies – in relation to the relatively trivial advances that are being made – it may very well be the case that these alternative technologies never displace fossil-fuels at all.
But, I hope I’m wrong.