Your gas tank is not an oil well. Your battery will not be a power plant.

Also published on Resilience

My car comes with an amazing energy-storage, demand-management-and-supply system; perhaps you’ve heard of it. It’s called the “gas tank”.

Thanks to this revolutionary feature, if I get home and the electric grid is down, I can siphon gas out of the tank and power up a generator. In a more urgent energy crunch, I can siphon out some gas, throw it on a woodpile, and get a really hot fire going in seconds. If a friend across town has no power, I can even drive over there, siphon out some fuel, and run a generator to provide power in an alternate location. It’s beautiful! I can shift energy provision and consumption both temporally and spatially.

There is one minor drawback, to be sure. If I siphon the fuel out of the tank then I can’t actually drive the car, at least not more than a few kilometers to the nearest fuel station. But let’s not let that limitation cast a shadow over this revolutionary technology. If this flexible load-management system were widely adopted, and there were cars everywhere, think how smoothly our society could run!

These thoughts come to mind when I hear someone rhapsodize about the second coming of the electric car. Recently, for example, a Grist headline proclaimed that “Your Electric Vehicle Could Become a Mini Power Plant. And that could make the electrical grid work better for everyone.” (June 21, 2021)

Stephen Peake, in Renewable Energy: Ten Short Lessons (review here) wrote that “new fleets of electric vehicles parked overnight could become another mass source of electricity storage and supply.” (emphasis mine)

One more example: an Oct 2020 article at World Economic Forum says that “When electric vehicles are integrated into a city’s energy system, the battery can provide power to the grid when the sun is down or the wind isn’t blowing.”

The key to this supply-and-demand magic is “bidirectional charging” – the electric vehicles of the near future will have the equivalent of a gas tank with a built-in siphon. Thus their capacious batteries will not only be able to quickly suck power out of the grid, but also to empty themselves out again to provide juice for other purposes.

But allow me this skeptical observation: electric car batteries do not have huge batteries because the drivers want to offer aid to the “smart grid”. Electric car batteries are huge because cars are huge consumers of energy.

(True, electric cars don’t consume quite as much energy as internal-combustion cars of similar class and weight – but they consume a whole lot more energy per passenger/kilometer than intelligently routed electric buses, trains, or especially, electric-assisted bicycles.)

And let’s be clear: neither an electric car vehicle nor its battery provide any “energy supply”. The car itself is a pure energy suck. The battery is just an energy storage device – it can store a finite capacity of energy from another source, and output that energy as required, but it does not produce energy.

As with internal-combustion powered cars, when the tank/battery is drained for a purpose other than driving, then the car ceases to be a functional car until refueled.

That will leave some niche scenarios where vehicle batteries really might offer a significant advantage to grid supply management. The Grist article begins with one such scenario: three yellow school buses which run on battery power through the school year, and serve as a battery bank while parked for the summer months. If all 8,000 school buses in the local utility service area were EVs, the article notes, their fully-charged batteries “could collectively supply more than 100 megawatts of power to the grid for short periods — or nearly 1 percent of Con Ed’s peak summer power demand.”

When parked for the summer, electric school buses would not need to be charged and ready to drive first thing every weekday morning. So they could indeed be used simply as (terribly expensive) battery cases for two or three months each year.

OK, but … let’s be careful about singing the praises of school buses. This might be a slippery slope. If big buses catch on, soon Americans might start taking their kids to school in giant pick-up trucks!

Of course I jest – that horse has already left the barn. The top three selling vehicles in the US, it may surprise people from elsewhere to learn, are pick-up trucks that dwarf the pick-ups used by farmers and some tradespeople in previous generations. (It will not surprise Canadians, who play second fiddle to no-one in car culture madness. Canadians tend to buy even larger, heavier, more powerful, and more expensive trucks than Americans do.)

The boom in overgrown pick-ups has not come about because North Americans are farming and logging in record numbers, nor even, as one wag put it, that a 4X8 sheet of plywood has gotten so much bigger in recent years. Yet urban streets, parking lots, and suburban driveways are now crowded with hulking four-door, four-wheel-drive, spotlessly clean limousine-trucks. Those vehicles, regardless of their freight-carrying or freight-pulling capacity, are used most to carry one or two people around urbanized areas.

If we are foolish enough to attempt electrification of this fleet, it will take an awesome amount of battery power. And as you might expect, car culture celebrants are already proclaiming what a boon this will be for energy transition.

A pre-production promo video for Ford’s F-150 Lightning electric pick-up truck gets to the critical issue first: the Lightning will accelerate from 0 – 60 mph (0 – 97 km/hr) “in the mid-4-second range”. But wait, there’s more, the ad promises: the battery can “off-board” enough power to run a home “for about three days”.

Keep that in mind when you start seeing big electric pick-up trucks on the road: each one, in just a few hours of highway driving, will use as much power as a typical American home uses in three days.

Keep it in mind, too, when you see a new bank of solar panels going up in a field or on a warehouse roof: the installation might output enough electricity each day to power 100 pickup trucks for a few hours each – or 300 homes for the whole day.

Given that we won’t have enough renewably produced electricity to power existing homes, schools, stores and industries for decades, is it really a good idea to devote a big share of it, right at the outset, to building and charging limousine-trucks? Are the huge batteries required by these vehicles actually features, or are they bugs?

Granted, an electric car battery can provide a modest degree of grid load-levelling capability in some situations. It can be drained back into the grid during some peak-power-demand periods such as early evening in the heat of summer – as long as it can be recharged in time for the morning commute. That’s not nothing. And if we’re determined to keep our society moving by using big cars and trucks, that means we’ll have a huge aggregated battery capacity sitting in parking spots for most of each day. In that scenario, sure, there will be a modest degree of load-levelling capacity in those parked vehicles.

But perhaps there is a better way to add load-levelling capacity to the grid. A better way than producing huge, heavy vehicles, each containing one battery, which suck up that power fast whenever they’re being driven, while also spreading brake dust and worn tire particles through the environment, and which significantly increase the danger to vulnerable road users besides. Not to mention, which result in huge upfront emissions of carbon dioxide during their manufacture.

If it’s really load-levelling we’re after, for the same money and resources we could build a far greater number of batteries, and skip building expensive casings in the form of cars and pick-ups.

Other factors being equal, an electric car is modestly more environmentally friendly than internal-combustion car. (How’s that for damning with faint praise?)  But if we’re ready for a serious response to the climate emergency, we should be rapidly curtailing both the manufacture and use of cars, and making the remaining vehicles only as big and heavy as they actually need to be. The remaining small cars won’t collectively contain such a huge battery capacity, to be sure, but we can then address the difficult problems of grid load management in a more intelligent, efficient and direct fashion.


Illustration at top of post: Energy Utopia, composite by Bart Hawkins Kreps from public domain images.

Sunshine, wind, tides and worldwatts

A review of Renewable Energy: Ten Short Lessons

Also published on Resilience

Fun physics fact: water carries so much more kinetic energy than air that “A tidal current of 3 knots has the same energy density as a steady wind stream at 29 knots (a fair old blow).”

And consider this: “Ninety-nine per cent of planet Earth is hotter than 1,000 °C (1,832 °F). The earth is, in fact, a giant leaky heat battery.”

Stephen Peake uses these bits of information and many more to lucidly outline the physical bases of renewable energy sources, including solar and wind energy, geothermal energy, wave energy and tidal current energy. But the book also touches on the complex relationship between the physics of renewable energy, and the role energy plays in human society – and the results aren’t always enlightening.

Peake takes on a formidable task in Renewable Energy: Ten Short Lessons. The book is part of the “Pocket Einstein” series from Johns Hopkins University Press (or from Michael O’Mara Books in Britain). He has less than 200 small-format pages in which to cover both the need for and the prospects for a transition to 100% renewable energy.

Key to his method is the concept of a “worldwatt” – “the rate at which the world uses all forms of primary energy.” Peake estimates the rate of energy flow around the world from various potential renewable energy sources. Not surprisingly, he finds that the theoretically available renewable energy sources are far greater than all energy currently harnessed – primarily from fossil fuels – by the global economy.

But how do we get from estimates of theoretically available energy, to estimates of how much of that energy is practically and economically available? Here Peake’s book isn’t much help. He asks us to accept this summation:

“Taking a conservative mid-estimate of the numbers in the literature, we see that the global technical potential of different renewable sources adds up to 46 worldwatts. There is a definite and reasonable prospect of humans harnessing 1 worldwatt from 100 per cent renewable energy in the future.” (page 31)

But he offers no evidence or rationale for the conclusion that getting 1 worldwatt from renewable sources is a “reasonable prospect”, nor how near or far “in the future” that might occur.

A skeptic might well dismiss the book as renewable energy boosterism, noting a cheery optimism from the opening pages: “There is an exciting, renewable, electric, peaceful, prosperous, safer future just up ahead.” Others might say such optimism is the most helpful position one can take, given that we have no choice but to switch to a renewable energy way of life, ASAP, if we want human presence on earth to last much longer.

Yet a cheerfully pro-renewable energy position can easily shade into a cheerful pro-consumptionist stance – the belief that renewable energies can quickly become the driving force of our current industrial economies, with little change in living standards and no end to economic growth.

Peake briefly introduces a key concept for assessing which renewable energy sources will be economically viable, and in what quantities: Energy Return On Energy Invested (EROEI). He explains that as we exploit more difficult energy sources, the EROEI goes down:

“As wind turbines have become larger and moved offshore, the EROEI ratio for wind over a twenty-year lifetime has declined from around 20:1 in the early 2000s to as low as 15:1 in recent years for some offshore wind farms.” (page 84)

Affordable renewable energy, in other words, doesn’t always “scale up”. The greater the total energy demanded by society, the more we will be impelled to site wind turbines and solar panels in areas beyond the “sweet spots” for Energy Return On Energy Invested. Peake’s book would be stronger if he used this recognition to give better context to statements such as “Renewable electricity is now cheaper than fossil electricity …” (in the book’s opening paragraph), and “solar is now the cheapest electricity in history” (page 70).

While Peake expresses confidence that a prosperous renewable energy world is just ahead, he doesn’t directly engage with the issue of how, or how much, affluent lifestyles may need to change. The closest he comes to grappling with this contentious issue is in his discussion of energy waste:

“We need to stop wasting all forms of energy, including clean renewable sources of heat and electricity. The sooner we shrink our total overall demand for energy, the sooner renewables will be able to provide 100 per cent of the energy we need to power our zero-carbon economies.” (page 141)

Near the end of the book, in brief remarks about electric cars, Peake makes some curious statements about EVs:

“Millions of [electric vehicles] will need charging from the network. This presents both a challenge and an opportunity in terms of managing the network load.” (page 130, emphasis mine)

And a few pages later:

“In the future, new fleets of electric vehicles parked overnight could become another mass source of electricity storage and supply.” (page 134 emphasis mine)

In my next post I’ll take up this concept of the electric vehicle as energy storage, supply and load management resource.

In conclusion, Renewable Energy: Ten Short Lessons is a valuable primer on the physics of renewable energy, but isn’t a lot of help in establishing whether or not the existing world economy can be successfully transitioned to zero-carbon energy.


Photo at top of page: Wind Turbines near Grevelingenmeer, province of Zeeland, Netherlands

 

the otters and the others

PHOTO POST

This post is mostly about “the others” – meaning those other herons who aren’t so well known as the Great Blue Herons. But some other others also have a way of popping into the photo opp when you least expect them.

And even the Great Blues, which you see almost every time you gaze across the marsh, can still surprise with new poses.

Meerkat Impressions, First Prize (click images for full-screen views)

This bird gave me a double-take, because I didn’t recall ever seeing a Great Blue stand so perfectly erect. Just a moment later the same bird looked a lot stouter.

Space Needle

What I really love about this time of year, though, is that the small herons make themselves visible too. The Green Heron and the Black-Crowned Night Heron both stay hidden most of the time in early summer, but now that their young ones have left the nest both adults and juveniles are out and about, particularly as the sun sets.

Whether you see much green in its feathers or not, the Green Heron is, in my considered opinion, one of the snappiest dressers in the neighbourhood.

Focus Right

But both the Green Heron, at left below, and the juvenile Night Heron, at right below, have beautiful and striking patterns that nevertheless can serve as great camouflage in many marsh settings.

Different Strokes

Young Night Heron at Dusk

Other than the distinctive red eye, the juvenile Night Heron looks only slightly like its dowdy parent, below. The elder sports a nifty long white plume, but otherwise keeps the design simple.

Night Heron, Plumage

The small herons keep their eyes open for small fish and frogs – and grab insects when they are close at hand. (Or close at foot; an insect landed on a Green Heron’s foot, below, and was snapped up in a flash.)

Very Light Supper

Whether in full light of day, the glow of sunset, or by the light of a full moon, there are few birds more striking than the Green Heron.

Listening Post

That being said, while you’re out looking for herons you never know who else might light up the evening. On one recent evening, a Wood Duck turned on the wattage before slipping back into the shadows.

Wood Duck Glow

And just as darkness falls, a couple times a year if you’re lucky, the Otters might suddenly join the party, splashing and diving and swimming circles around each other.

Surfacing

While you watch them they periodically perform an “up periscope” routine to get a closer look at you. And then after a few breathy barks, they suddenly disappear among the lily pads and the waters are still.

Pop Goes the Otter

the fullness of summer

PHOTO POST

The afternoon sun is hot, but the evening air cools. Gardens and marshes are lush and green, but golds and reds peek through. Fruits ripen, seeds swell. The fullness of summer is now.

Wood Duck in a Rippled Mirror

A young Spotted Sandpiper (the spots will come later) hunts in the shadow of lily pads.

Sandpiper seeks Shadow

The full-grown pads easily support the weight of these diminutive birds.

Sandpiper seeks Light

The lily pads may also hide supper – a frog, perhaps? – for a Great Blue Heron.

Blue on Green

Closer to home a Blue Jay relaxes in the early-morning sun.

Blue Jay with Tall Grass

The hundreds of Red Soldier Beetles that gathered on a Hydrangea Paniculata were not ready to relax.

Busy Beetles

Mushrooms pop up every day and many, like these on a wood chip path, won’t stand up to the mid-day sun.

Sprouting through the wood chips

The Tomatillos in the garden, on the other hand, love the August sunshine as long as they get enough water.

Tomatillo Forest

The Sour Cherry crop is now put away – and our resident Chipmunks were glad to help in the harvest.

Ground Squirrel out on a Limb

Cherry Chipmunk