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Archive for August 2017

Logical fallacies and the environment: correlation and causation

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Last year I published a series about logical fallacies that abound in pronouncements about environmental issues (here is an installment, as an example).  But I recently came across one of the best examples that illustrate how correlation and causation are distinct.

The example comes from the recent book by Anurag Agrawal, a world authority on monarchs.  Monarch numbers are clearly in decline, but what is causing it?  There are multiple causes, as always.  One possible cause that has often been pointed at is the use of GM corn and soybeans.  These plants are resistent to herbicides such as Roundup (glyphosate), and therefore much more of the herbicide has been sprayed as before.  If the drifting herbicide is also killing milkweed, it would deprive monarchs of their food source (monarchs eat only milkweed – nothing else).  Could that be the main reason that monarchs are becoming rarer?

On page 236 of the book, Agrawal proposes a graph (reproduced below) that seems to indicate that this is the case.

The caption reads: a) correlation between the percentage of genetically modified, herbicide-tolerant corn and soybeans planted each year in the United States and the monarch overwintering population size in Mexico, and b) the number of cell phone subscriptions in the United States and the same estimate of monarch populations.  Each point represents a year (1993-2014).  Note that the points are not in chronological order.

The top graph seems to strongly indict the GM plants, doesn’t it?  But wait, the bottom graph shows that maybe radiation from cell phones is to blame.  This is not as farfetched as it may originally seem: we still don’t know exactly how monarchs orient themselves for their yearly migration to mexico, and it is conceivable that the EMF from the now cell phones and towers is affecting their ability to navigate using the magnetic field.

But if the monarch decline is plotted against the S&P January stock market values, we get as strong a correlation – what is going on?  The reality is that all three correlations are very strong because the percent of GMO plantations, the number of cell phones, and the stock market have all increased over the time period under consideration, while the monarch numbers have consistently declined.  Agrawal states clearly that the correlations, in themselves, are not an indication of what is causing the decline.  (He also indicates that this doesn’t get the GM crops off the hook, either – merely that causation and correlation are different.  Saying that the fact that this is a mere correlation shows that GM crops are innocent would be equally spurious, a case of either-or fallacy).

The book is full of little gems like this, and I thoroughly enjoyed it – I recommend it to anyone interested in ecology.  If time permits, I will try to post a true review.  But meanwhile, for completeness sake, in case anyone doubts that monarch numbers are declining, here’s the data (from page 214):

We do have a bit of a crisis on our hands, when it comes to the monarch.  But thankfully, this is not the main theme of the book; co-evolution, with all its mysteries and wonders, is what the book is about, and it is written in a very accessible style.  Meanwhile, though, here’s the key lesson: one can really easily find correlations by plotting against one another the Y-axis of time series that have strong time trends.  And quite likely, just as easily can you use it to convince folks that you’ve found the environmental culprit!  But don’t.



Agrawal, Anurag 2017.  Monarchs and milkweeds: a migrating butterfly, a poisonous plant, and their remarkable story of coevolution.  Princeton U Press.

Written by enviropaul

August 11, 2017 at 12:02 pm

Electric cars and the Formula E race

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Yup, those are electric cars

Last weekend Montreal hosted the Formula E grand prix: a car race, similar to a Formula One, except that all cars are electric.  It has been popular, if controversial.  If you call yourself an environmentalist, do you cheer such races, or boo them?

For engineers and other geeks, there’s a lot to like about the event.  This is where electric mobility is put to the ultimate test.  Despite the fact that the cars are restricted in top speed (225 km/h) and maximum power ( 170 kW, equivalent to 225 horsepower), there is still plenty to work on.

Electric cars have batteries, which much get recharged; this is done using a converted diesel generator that runs on glycerin, a by-product from bio-diesel production that burns cleanly and is carbon neutral.  (Glycerin is also a feedstock of choice for biogas generators.)

The cars typically have a single engine, and – atypically for electric cars – a gearbox to optimize power regime; innovations such as torque vectoring (giving more power to the outside wheels during a turn) are forbidden.  A unique energy boost of 100 kilojoules is granted to three drivers selected by fans.  And then there are all sorts of technical tweaks beloved of fans, for getting more power and more efficiency out of things such as software power control, regenerative braking, battery thermal load management, and the like.

Many of the innovations tested on Formula E circuits end up in production cars.  Jaguar, for instance, which fielded cars last weekend, uses the platform to test and improve the performance of its I-Pace system  that powers its brand new all-electric SUV.  Says  Alain Leynaert, product planning manager for Jaguar

The I-Pace is sharing the same electric motor technology as the race cars. We’ve been asked why aren’t we using the same motor as Tesla. From our perspective, what we’ve seen is there are packaging and thermal benefits to the permanent magnet motor so we’ve decided to go that route.

This racing is really the most extreme testing you can ask for. What we see happening in the road car is just a snap shot of the extremes that the race car goes through. If we can manage to make the race car run well and be thermally reliable, it translates right into the passenger vehicle.

These are some of the benefits of this type of events: better electric vehicles.  Another set of benefits is public awareness: there are still many people who look at electric cars as glorified golf carts.  They are anything but, obviously; yet the two share something that fossil-fueled race cars don’t have: they are remarkably quiet, and they are pollution free.  This is why the races are held in an urban setting (downtown Montreal in this case): to show that, aside from the controversial road closures, there is little impact.  And this race had plenty of drama: there was a spectacular crash during the qualifying rounds as the current title holder, Sebastien Buemi  of Renault, crashed into a wall at high speed.  The car was repaired but eventually disqualified for being underweight.

So, overall, a good show, heralding the coming of the electric car.  Some people still poo-poo it (witness car commentator Motormouth here); others praise it.

Some of the commentary cautioning against widespread electric car adoption claim that it simply displaces pollution.  If the local electric power is produced by coal, isn’t that actually worse?  Well, no, it isn’t.  It may be in terms of ordinary air pollutants such as nitrogen oxides, if coal power plants are not equipped with pollution control devices as good as cars.  But this isn’t really the main point: rather, it’s about greenhouses gases.  According to some (such as Luc Vallée and Jean Michaud), it may actually be worse for the environment if coal is burned to make the electricity used in e-cars.  But this is a canard; an electric car is so efficient at converting electricity into motion that, even fuelled by coal-generated electricity, the production of carbon dioxide is still much lower than that of a similar gasoline or diesel vehicle.  That is because an electric car can convert over 90% of its electric charge into motion; an internal combustion car, only 20% at best (that’s why the radiator gets so hot: most of the energy disappears as heat).  In contrast, large coal (or natural gas) power plants have an efficiency of about 40%.  You can do the math: a combination electric car/coal plant is still twice as efficient as a gasoline car, and so emits only half the carbon dioxide for the same trip.  Unfortunately even Globe columnist Eric Reguly, who should know better, has fallen for that nonsense.

A better question may be: what would happen if all cars were replaced by electric cars?  Would that not strain the grid to the point of failure?  That is the line followed by proponents of big new projects, from Site C to the UK’s proposed Point Hinckley nuclear plant, a costly and unnecessary boondoggle if ever there was one.  Without question, this would indeed represent an additional demand to the system.  Ryan Carlyle calculated that, should all cars in the US turn into electric vehicles at the stroke of midnight, the electricity demand would increase by 29%.  (He also calculated that, with the current mix of power generation in the US, carbon dioxide generation would be reduced by 6% – so there, Reguly, Michaud and company.)

So an environmentalist may rejoice at the (smallish) reduction in CO2 emissions that electric cars represent, but blanch at the prospect of environmentally destructive megaprojects to boost electricity generation.  And it’s not just cars: much of our land transport, road and rail, could conceivably be fuelled by electricity, to say nothing of space and water heating, and many other uses of electricity that could replace fossil fuels and reduce greenhouse gas emissions.  Electric utilities have been considering this to justify forecasts of huge future demand increases.  They have a record of consistently over-predicting future demand ever since the 50s – but could they be right this time?

Not so fast, though – there are several trends and technical developments to consider, which complicate the situation considerably.  The first of these points is dispatchability, that is, the ability to generate electricity at the time when it is needed.   But cars do not typically consume power during peak demand times; power is needed when batteries get recharged, and this takes place most of the time at night, when demand is lowest.  Recharging a big fleet of electric vehicles may actually stabilize the grid; while more electrical energy would be consumed, the power capacity of the system would not need to increase, in this scenario.  That is because the power plants that we currently run have more than enough capacity to meet the recharging demand during off-peak hours.

The second trend to consider is increased efficiency.  Take lighting, for instance: the same brightness can be achieved with LEDs as with incandescent bulbs using less than 10% of the electricity required by the traditional bulbs.  The same is true for a variety of machinery, from electric motors to air-conditioners, computers to televisions, or data acquisition and control systems.  As technological breakthroughs keep happening, the overall demand for electricity of western societies is expected to drop.  So even if electric vehicles create an additional demand, that demand may well be canceled by efficiency gains elsewhere in the system.

The third trend that matters is the nature of electricity generation, itself, which is becoming decentralized.  Wind and solar power may be intermittent, but decentralized generation with matching storage means that grids are becoming much more robust than previously, not the other way around; the best test of this was the solar eclipse that occurred in Europe last year.  Many pundits expected black-outs and brown-outs from all the solar collectors going suddenly off-line, especially in countries heavily solarized like Germany; but the eclipse came and went without any hitch.  In practice, this could be as simple as charging a car at home using electricity from one’s own solar panels and batteries.

But most important is the trend away from cars.  A much smaller proportion of young people own cars or even have a driver’s license than a generation ago.  This is thought to be the result of a combination of factors, from a diminished value as status symbol (electronic gadgets replacing them) to improved transit and car-sharing.  As Eric Doherty eloquently describes, car-oriented projects that a few decades ago seemed fine are now considered absurd, such as the proposed ten-lane bridge over the Fraser.

So the demand for private cars is waning; and the demand for gas guzzlers is definitely dropping, with an end in sight.  Evans-Pritchard writes in the National Post that

OPEC and Big Oil thought they had 50 years. At best they have a decade…Just like what happened to Kodak when digital cameras appeared — the end will be swift and brutal.

So private cars may be on the way out, and that means less congestion, less noise, and fewer accidents.  But even so, the private car is not likely to disappear any time soon, if ever.  Tesla, now the darling of investors, has just announced the launch of its cheaper Model 3; there are already half a million customers who have plunked down a deposit to secure one.  China is now the biggest market for, and producer of, electric cars.  Germany plans to have one million electric cars on the road by 2020.  Electric cars already make up 40% of all cars sold in Norway.  The Nordic country, along with the Netherlands, will ban sales of fossil fuel cars by 2025; France and the UK plan to follow later.  Mining investors recognize that the demand for electric vehicles is already affecting the price of metals, particularly lithium and cobalt, but also aluminum, lead, and copper.   Shell’s CEO, Ben Van Beurden, has announced that his next car will be an electric one.  Electric cars are coming, like it or not.

I’m not much into car culture.  But if ever Formula E comes to Vancouver, I’ll enjoy the show.  With a clear conscience.

Written by enviropaul

August 5, 2017 at 5:06 pm

Dispatchability…uh, what?

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The emninetly dispatchable power of Dinorwig, a former quarry in Wales turned hydraulic storage

Today (8/8/17) SFU’s Mark Jaccard chimed in on the Site C debate with an opinion piece in the Vancouver Sun about dispatchability. Huh?

What appears to irritate Jaccard, a highly influential scholar and environmentalist, is the often repeated claim that while the costs of Site C keep climbing, those of renewables keep dropping.  By the time the Site C dam is completed, wind and solar will be so cheap that BC will be saddled with a white elephant.  Not so fast, says Jaccard: the real comparison should made on the cost of dispatchable electricity, not simply the price per kilowatt of capacity, nor that of produced electricity in kilowatt-hours.  Rather, what matters is the cost of producing electricity at the time when it is needed.  For instance, wind electricity that is only produced at nighttime, when no-one needs it, would indeed have indeed very low value; conversely, wind that reliably produces electricity at peak times (typically late afternoon), would be worth much more.  Dispatchable electricity, that is, electricity that can be matched to the demand, is indeed much more valuable.

Jaccard should be applauded for introducing this fairly arcane concept into the discussion.  As the Utilities Commission, which is finally reviewing Site C, drafts its recommendations, the concept of dispatchability is likely to get more airplay – and generate further confusion.  Forewarned…

That said, I expect this editorial to be embraced by the defenders of Site C.  Jaccard, wisely, does not pronounce himself on the issue.

That may be because, ultimately, dispatchability is unlikely to be a key issue.  Jaccard mentions that a large reservoir, such as would be created by Site C, does  provide dispatchability because of its ability to store water and release it only as needed.  A large hydro-electric reservoir is an ideal match for an intermittent source such as wind or solar.  Indeed, according to Jaccard,

As we invest in more wind and solar, the economics of dispatchable sources like Site C improves.

This is counter-intuitive, but true – in general.  But this is very unlikely to be true of Site C, itself.  This is because Site C would create just another reservoir, one among many in the province.  Site A, where the WAC Bennett was built, is a case in point: it created Williston Lake, a reservoir that dwarfs the proposed reservoir that Site C would create in the Peace valley.  And there are many more, of course: just think of Kootenay Lake or the Arrow Lakes to get an idea of the storage capacity we already have.  We are already well equipped to partner with any increase in intermittent power such as wind or solar.

Jaccard also mentions that other energy storage options, such as batteries, are much more costly than its equivalent capacity in a large hydroelectric reservoir.  But this is the same refrain as was said last decade about wind and solar: too expensive.  As larger and larger storage systems come on line (such as  the newly announced projects in Hawaii and Australia), unit costs per unit power are going to drop, just as they did for solar, because of the economies of scale in manufacturing, as well as new technical developments.  True, we’re not there yet, but there is no reason to expect that batteries would not follow a price curve similar to solar cells or computers.  In contrast, if Muskrat Falls is any indication, the price of Site C is going to keep soaring skywards.  I have not asked him, but my guess is that Jaccard’s prudence and lack of commitment on this issue comes from the fact that he knows these facts, just like Andrew Weaver does.  And like Weaver, I expect Jaccard to eventually admit, sooner or later, that Site C is unnecessary.

But if nothing else, Jaccard has the merit of introducing the concept of dispatchability to the general public, at least to those who read the papers.  If it becomes a household word, I fully expect the geothermal energy folks to start trumpeting: “Hey, we’re dispatchable! Invest with us!”

And a good thing that would be.

Written by enviropaul

August 4, 2017 at 3:40 pm