Dispatchable hydropower versus pumped storage, Round 2

Glen Canyon Dam Tapped for Emergency Water Releases to Meet California Power Demands (Arizona Republic, Phoenix, AZ)https://t.co/BsrRZIfUN6

— Energy News Digest (@energydigest) August 19, 2020

I've been meaning to return to this concept of dispatchable hydropower and distinguishing it from pumped hydropower storage. The tweet above shows how one example of it being used in practice. We could do much more, somewhat to help in energy crises similar to what's happening now in California, and more to smooth out renewable power-based systems generally.

Sammy Roth publishes some great work about climate and energy, and recently published eight low-carbon solutions to variability in renewable power. Pumped hydro was one of them, while dispatchable hydro was not. Glen Canyon Dam suggests it should've been.

Dispatchable hydropower is (mostly) distinguishable from pumped hydro storage in that it makes use of existing dams and reservoirs, and (mostly) doesn't build new infrastructure like pumped hydro does. Its focus is a change in how hydropower is used and released from baseload power that's used constantly, first in line to satisfy demand, to dispatchable power that - subject to other constraints that require release - is conserved and then released when needed.

I previously had some documents that I'll try to dig up from my local Community Choice Energy Aggregator that showed essentially no 24-hour variation in the hydropower they received, and that's the type of baseline use that could be saved, somewhat, for the late afternoon and evening hours when demand is up and solar is down.

I also want to distinguish this from Mark Jacobson's Wind Water Solar system for replacing all fossil fuels. He's proposing something gigantic, I'm discussing something much smaller and therefore able to be implemented much sooner. In particular, what I had read a while back was that he wants to quadruple the dispatchable power from existing dams by rebuilding their outlets. I don't know how well that would work, but I do know it would require dewatering and then mostly or entirely rebuilding the dams themselves. I'm not talking about that.

These ideas do shade into each other a bit. You can't fully turn off and turn on water from dams, they have ecological and water supply reasons for running as well. Some construction might also be helpful for dispatchable hydropower, particularly an afterbay below a dam that stores a tiny percent of the total water, maybe a day's worth or more, and can modulate the downstream releases from the main dam. The expense would be small though compared to other massive projects, or you can just not do it and still use some limited flexibility in water releases to time them for dispatchability.

Using that power in this manner could help in the shortages California is facing now, and maybe elsewhere too, along with batteries and everything else we can do to reach 100% carbon free economies.

Renewables up, gas down, and coal at less than half capacity

Interesting report by think tank Ember on state of energy transition, comparing the first half of 2020 to 2019 and also looking back to 2015. Over five years, solar and wind doubled worldwide from 5 to 10 percent of generation, and coal's share unsurprisingly decreased by 5 percent in that period.

Comparing first halves of 2020 and 2019, solar and wind generation rose 14% despite decreasing electricity demand due to covid, while gas decreased 1.6%. This is an especially early indicator of renewables starting to outcompete and reduce gas generation, not just coal, even without fully pricing carbon. I say "especially early" because I assume gas will bounce back for 5-10 years as electricity demand recovers and gas has more opportunity to replace coal. But as renewables rise into the range of 15-25% of the total, they'll take out some gas generation.

Coal took the biggest hit in generation in 2020, falling 8.3% compared to 2019, again unsurprising that in a period of reduced demand, the most expensive operating-cost input would decrease the most. With that, already somewhat-idle coal plants dropped to now using 47% of their capacity.

Plants straining at 100% capacity are probably not the most efficient, but neither are plants that are mostly unused. In a free market a lot of these plants would probably be closed down permanently. Most places don't have a free market, but they still are influenced by economic forces. If demand for coal doesn't go up after covid, and it's doubtful it will outside of Asia, then I'd expect to eventually see shutdowns.

So good news globally, although as the report says, this decline still isn't fast enough to keep warming to 1.5C. We're really going to have to work on carbon-negative policies.

In the US specifically, a mixed bag: coal's taken a huge hit, generation down 31% and capacity at 32%. OTOH gas generation increased 7% - not as much as solar/wind's 16% but more in overall watts, for now. Still not a bad result with an anti-science, pro-coal administration. Let's look forward to January 2021, hopefully.

Note BTW that I used "renewable" and solar/wind interchangeably for purposes of this discussion although renewables is a bigger/more amorphous category. Also some wags might point out that solar/wind typically operate at significantly less than 47% capacity, but the difference is that they are designed and priced at the level of generation compared to capacity, and coal is not.

Who's Next

 Brian and MT hav already taken some free whacks at Michael Shellenberger, but Eli would a couple too. In a truly deranged article at Forbes Shellenberger goes fully insane 

Who Are We To Deny Weak Nations The Nuclear Weapons They Need For Self-Defense?

Now Eli knows that foresight was never the Breakthrough Institutes forte, given their inability to go beyond the bright shiny thing they see in the candy store window, but Michael Shellenberger needed to grow up sheltering under his desk.

Of course one could put together a carefully reasoned replies to this, but why bother when it has been done 50 years ago, and with rhythm. Going back to the old days of the nuclear arms race Tom Lehrer put it well

and as to the other side there will be universal bereavement, for Shellenberger an inspiring achievement, we will all go together when we go.

Shellenberger has always been a boy playing with toys, not able to figure out that sticking his finger in an electrical socket is not a great idea. As Oliver Cromwell put it, Dear Michael, in the name of God, go. there is more, but it fits so well

Tobis shellacs Shellenberger

Peeking out of my hutch momentarily (maybe longer) to highlight Michael Tobis' piece at RealClimate, taking apart Michael Shellenberger's twelve non-facts he's flacking in support of his non-nonfiction book.

I'll just add a few snarky stretches of my own responding to the nonfacts but read MT for the main discussion.


1) Humans are not causing a “sixth mass extinction”

Yes we are.

Moving on to Shell's other claims....Or does it deserve more response than that? I've never gotten around to blogging my own definition of the Anthropocene Epoch, but I think that some millions of years from now, whatever corresponds to paleontologists will begin the Anthropocene about 50-60k years BP, when the fossil record demonstrates that humans showed up in Australia and the Australian megafauna went away. Sixth extinction started then, sputtered along for a while, and flared up when humans showed up in the New World and the New World megafauna went away. Sputtered some more and then picked up the pace with invention of agriculture (and pastoralism), and then went to conflagration with the modern age. The mass extinction is well in hand looking at megafauna - maybe it'll take some time to see when counting marine molluscs, but that doesn't change the issue.

On top of that, the many species that aren't technically extinct, are functionally extinct in the wild. Shellenberger's claim is that these species aren't gone, but unless you posit a future where they replenish, then those future paleontologists millions of years down the line are unlikely to dig up the few animals that were hanging out in a zoo. If you are going to take off Shell's blinders and look at the future realistically though, then real extinction and real mass extinction are the likely short-term outcomes.


10) Habitat loss and the direct killing of wild animals are bigger threats to species than climate change 

Funny how Shell put his two biodiversity arguments nearly as far apart as possible from each other. Hunting and other direct killing are of little relevance to extinction for anything other than large fauna which I thought weren't important enough to Shell to count as a mass extinction (I'll concede overfishing is a big problem). Habitat loss - yes, nearly 10k years of habitat loss to farming combined with the last 200 years of massive population growth are more influential than climate change to date, but Shell is ignoring how climate change makes habitat loss much worse. Climate change makes existing habitat uninhabitable, and habitat loss makes it impossible for species to move to refugia, or eliminates the refugia. Pretty ridiculous for Shell to say something that makes a catastrophe 10% worse (and deteriorating) is somehow not so bad.

And btw, marine mollusc extinction is not as likely to affected by habitat loss and overharvesting as opposed to climate change.


3) Climate change is not making natural disasters worse

This old canard, originally from Roger Pielke Jr. Read MT for more, but it is in part a signal/noise thing, or better what I think James Annan described as detection/attribution, where we can appropriately attribute an increase in disaster impacts to climate change even if you can't hit 95% certainty on detection.

My other point that I made as far back as when I stupidly thought RPJr worth corresponding with is that an enormous amount of cost is built into preventing disaster, from seawalls to more expensive building standards, and that cost is ignored by his standard and is a cause that reduces his cost impact measurement. It's annoying, so I'm sure he'll continue it.


5) The amount of land we use for meat—humankind’s biggest use of land—has declined by an area nearly as large as Alaska

Like MT says, more accurate than most of his points but of little relevance. Also I've read elsewhere that between some or all of the decrease in pastoral land is made up for by increased farmland, often to feed livestock (sorry, can't find the link). That's not a good exchange from an environmental perspective.


6) The build-up of wood fuel and more houses near forests, not climate change, explain why there are more, and more dangerous, fires in Australia and California

I've written an Op-Ed on this! Kind of like habitat loss and climate change - land use/abuse currently is more important, and climate change makes it worse, with a worsening trend.


9) We produce 25 percent more food than we need and food surpluses will continue to rise as the world gets hotter

I agree with MT that most of the world will be able to handle future food crises. Subsistence farmers will not. If it's possible to separate ethical and environmental impacts, then I think the greatest ethical impact from climate change will be malnutrition and death among the poorest people in the world due to changed weather, especially changed rainfall. The greatest environmental impact will be the effect on biodiversity because that will take millions of years for recovery, as opposed to merely tens of thousands of years for the atmosphere and oceans to recover. But Shell isn't worried about biodiversity.

The rest is silly, and again MT takes care of it.

Germany requiring gas stations to have EV chargers

From Electrek:

As part of Germany’s new increased electric-vehicle incentive package, the country will require gas stations to offer EV charging. Details about the plan are not yet known, such as the timeline and type of required chargers. But EV advocates quickly praised the move as a boost to electric-car adoption.

BDEW, Germany’s association for energy and water industries, believes that at least 70,000 charging stations and 7,000 fast-charging stations are required to achieve a mass market for EVs in the country. BDEW reports that there are currently about 28,000 stations in Germany.

According to Reuters, electric cars made up only 1.8% of new passenger car registrations last year in Germany, with diesel and petrol cars accounting for 32% and 59.2%, respectively.

I think I agree with Electrek's opinion of this news:

We’re not sold on the idea that gas stations are the best location for EV charging, especially if Level 2, 240-volt charging stations are used. On the other hand, petrol stations situated along expressways and equipped with ultra-fast EV charging make more sense.

Look at where Tesla and Electrify America, among others, are locating quick-charging stations: near amenities, like shopping centers, hotels, and restaurants, where you might want to hang out for 30 minutes.

A 240-volt charging station that adds about 25 to 30 miles in an hour is definitely not the right choice for a gas station. That said, many German gas stations have a level of amenities not offered in the US. Moreover, the visibility of seeing EVs plugged in sends a message that charging is abundant, and range is not an issue.

The decision to require every single gas station to offer EV charging is a little odd. It applies an outdated combustion-oriented frame of mind to new technology. The sentiment is great, but let’s hope the details get sensibly worked out when it comes to implementation. 

Maybe Germany has more gas stations with amenities where people theoretically could hang around than in the US, but that doesn't mean people will want to hang around, and still there are all the other gas stations without much in the way of amenities. Ironically, the costs of installation might actually close down some stations that were on the edge of solvency, and I expect there will be more of them shutting down over time. The infrastructure for ICE vehicles will get spotty, and is unlikely to be supported in many places just by adding EV chargers.

A low-key protest

I've been wearing this mask since the end of April. Every day I've been out, I've been complimented about it. I originally meant it as a reference to covid, but I think it applies to the current situation too. Anyway, all you need is a fabric marker to make your own. pic.twitter.com/QgChsPTDjW

— Brian Schmidt (@BSchmidtTweets) June 3, 2020

Good Intentions

To be honest, and Eli is always honest, good intentions slip away when one is sleeping through a lockdown, one day like another, and another and another and one simply stays in bed and does not visit Rabett Run muchly

However to continue where we left off, Eli has come across a a rather nice way of showing how absorption of thermal radiation in the atmosphere warms the surface.

Start with the simplest case the surface of an Earth whose atmosphere does not absorb infrared radiation. Solar energy q falling on the surface warms it until the surface can radiate an equal amount of energy. The temperature at which this happens is given by the Stefan-Boltzman equation.

Ok, this is a bit simplified, no albedo, all the energy is absorbed and none reflected and the emissivity of the surface is unity, no view factor, but that can be added back in later, here all Eli wants to do is establish the principle.

What would happen if we added two absorbing layers between the surface and space

Since the heat, the net thermal energy passing between each layer has to be the same as the heat going into the surface, q, there are three equations. At the top, the heat, being radiated to space is just the same as the heat injected at the bottom, and is given by σT₂⁴. 

Between the first and second layer the same amount of heat, q, is transferred. In this case, q is the net difference between the thermal energy transferred upwards as shown by the blue arrow and the backradiation from the top layer shown by the orange arrow. Note that at the top the backradiation equals the radiation emitted to space which in turn is equal to the radiation absorbed at the bottom. Conservation of energy and all that.

At the bottom, the heat transferred between the surface and the first layer is also q, but in this case the difference is between the upwards thermal radiation from the surface, σT₀⁴ and the backradiation from the first layer σT₁⁴

Three equation, add them up, and you get that 3q = σT₀⁴, solve for T₀ and compare to the result with only a surface. The temperature of the surface is warmer by a factor of 3^1/4 or if you want numbers about 1.3.

By inspection (instructor speak for do the work) if you had N layers the surface would warm by a factor of  N^1/4 while the input and output of heat from the system remains constant. 

Vacuum ovens use this principle with multiple heat shields to slow the transfer of heat from the inside to the outside and that is where Eli first came across them when he was but a little guy building his own systems. (not nearly as neat as this one). Looking closely there are about 7 layers to the cake here.

There are a lot of discussions on line of one layer energy balance models for the Earth's atmosphere which explicitly include emissivity and albedo, coming up with an effective emissivity of about 0,77 across the entire IR spectrum, but the multilayer POV puts paid to the argument that backradiation can't make the surface warmer