Guest post by Rud Istvan,
Here we are again on another Charles request, this time just summarizing the essence of several previous related and much more detailed renewables dissections at Climate Etc. Those previous posts were co-authored with electric utility ‘Planning Engineer’– (who after his recent retirement is invited to comment on this here also).
The specific issue Charles highlighted for possible comment was a newish article at the ‘irrefutable’ Atlantic. It claimed that but for President Trump’s intervention, the ‘Green New Deal’ (GND) grid could have been stabilized by nationwide grid connected GND renewables.
This article is more ‘fake news’ nonsense for several separate technical reasons, independent of the fact that the sun sets nationally so night is still a big solar problem as California is finding with its rolling blackouts, whether or not there is national grid—although AOC might think it helps.
First, voltage sags with distance thanks to resistance (a bit more complicated in the alternating current Tesla domain, but still true as the main reason Nicola Tesla (Westinghouse alternating current) beat Edison direct current (GE) for our present several large regional grids. Even a very high voltage national AC grid would lose some of its electrical energy: per regional experience, transmission grid energy losses would be on the order of 15%. That is why very long links tend to invert to HVDC, then revert to AC, as the Scandinavian/EU interconnectors do. There are inverter losses, but less than AC losses at higher distances. There are several other practical engineering reasons the US high voltage grid is still NOT nationally interconnected, even though it theoretically could have been from a purely technical perspective. None have to do with President Trump.
Second, wind and solar lessen grid stability because they lack grid inertia. So the more renewables penetrate, the less the needed grid inertia provides voltage (manifested as AC frequency) stability. More renewables means less grid inertia, thus more grid frequency instability (evidenced as (‘brownout’ voltage sag) that can shut the entire grid down to protect all the classic spinning generators. Massive rotating steam/gas turbine generators (several hundred tons each) also store kinetic energy for the grid via their simple rotational momentum. The grid demands more energy, they offer up the momentum and begin to slow down, and the ‘steam/gas’ turbine responds and powers them back up to keep their rotational frequency generating speed ~constant.
Neither wind nor solar have this inherent kinetic energy momentum ‘capacity’, since both are asynchronous. They lack ‘grid inertia’. So their addition to any existing grid increases its potential frequency instability. That is not a problem if asynchronous penetration is a small percent of the total generation. It is a BIG problem if their penetration becomes significant (>~10% or about equal to conventional rotational momentum spinning reserve standby capacity).
There is a grid inertia solution, but at great additional grid cost ignored by GND. You can add synchronous condensers in an amount equal to renewables. These are essentially big undriven (no attached turbine) generators spinning synchronously with the grid AC. They can provide the grid inertia renewables lack. But are ONLY necessary with renewables; wind farms and solar operators need subsidies BEFORE the added costs of underutilized backup power and synchronous condensors. They are hopelessly uneconomic. In Climate Etc. essay “True cost of wind” we redid the grossly erroneous Obama era EIA estimate of onshore wind compared to coal and gas. The lifetime cost of energy (LCOE, an annuity calculation) of CCGT is about $56/MwH. The true cost of wind, using the Texas ERCOT grid for some of the specifics, is about $146/MwH. About 2.6x higher. Not a little bit higher, more than two and a half times higher. And that was without adding synchronous condensers.
Third, a nationally connected grid still does not solve three other separate renewable intermittency problems.
(1) First, the sun always sets, albeit about 3 hours later on the US west coast than on the east coast. There is still much mutual night on both coasts. So there is always insufficient solar offset for the evening hours (dinner cooking, AC, laundry) on a US national grid. Florida cannot save California.
(2) Second, energy demand is always seasonal. The sun sets early in winter when additional energy is needed for heating. No national grid can solve northern hemisphere seasonality.
(3) Third, wind is still highly variable by location. There is no mathematical assurance that on average it will ever be average across the US. The windiest places in the US (north Texas, western Iowa) still have capacity factors averaging about 32% of nameplate capacity. So 2/3 of the time, not enough wind even in the best locations. No different than the same meteorological problem covering much smaller Europe. But for French nuclear and Scandinavian variable hydro, German wind renewables would already be toast.
The Atlantic should have stuck to its previously justified fame, satirical political cartoons. Rather than now becoming several itself.
Addendum from Charles Rotter:
I believe this tweet thread below from David Reaboi sums up nicely what happened in this instance covered by the Atlantic.
Reaboi is talking about issues at DHS, not the EPA, but this pattern has been repeated for the last four years throughout Federal agencies. If anyone wants to do some FOIA leg work, we’d all love to see this brilliant plan to ease renewable energy issues.
(1) ANATOMY OF AN INFO OP. You’re a Democrat career civil servant somewhere, and you hate the president, who’s a Republican. You want to undermine him, and also advance your own political and ideological goals. How do you do it?
(2) You write a report that dovetails with your ideological thinking, but one that has no support from your bosses, the administration, or even reality. It doesn’t even have to be coherent or factually sound.
(3) When it’s laughed out of the room, you leak it to the media–as you’d always planned to do. The media runs the initial story like, “see, even Trump’s own DHS doesn’t think Antifa and far-left terrorism is a priority, or even a problem!”
(4) Then, once the DHS report is scrutinized inside government and subsequently rejected–guess what? Media has another story: “Truthful report censored by Trump!”
(5) When a legit report comes out–say, about Antifa and its documented anti-American activity and violence–the media casts it as “politicized.”
(6) The people who do this are loathsome. They know exactly what they’re doing, and that it’s an effort to undermine. The media knows it, too– they’ve got the whole story arc of these pieces already planned out before the first one runs.
Originally tweeted by David Reaboi (@davereaboi) on September 9, 2020.
You know, there was a time when socialists and progressives…cared about power costs. Charging Bill Gates or Warren Buffet an extra $50/month for electricity is no big deal. But doubling or tripling the cost of electricity is a huge deal at the bottom of the economic ladder. And they literally …don’t care. Couldn’t care less if poor people are harmed by their polices. their callous natures coupled with ignorance is just terrifying.
Oh they have a plan for the impoverishment they bring to the ever expanding lower middle classes… re-distribution to buy votes. Take money from the increasingly thinning middle class that is the real driver of the economy and give to the tribal underclass they have created for increasing political power at the ballot box. It is what Hugo Chavez did to Venezuela. It is how California Democrats are cementing their strangle hold on Cal’s middle class wealth to re-distribute. Don’t underestimate the March to Socialism as a powerful lure that depends on basic human behaviors in an uneducated population to its pitfalls.
You have missed one other good reason why the USA is split into separate grid regions – the speed of light.
Essentially if you have two wires of different lengths arriving at the same place, and AC signal will be slightly different in phase from one wire to the other, and this leads to large power factor type losses – yes its part of the resistive loss, but it’s not just about delivering power through a resistance, it’s about delivering ‘wattless current’ through a resistance.
That is why the USA has three synchronous grids instead of one. Because actually in terms of resistance grids do not send power from one end to the other. If you look at the resistance paths its clear that generators will supply more current to loads near them, and indeed the grid is not sized to carry full load current over its entirety – it is more a balance and emergency overload supply.
So:
Local generators in general feed local loads, lending and borrowing a bit of power from the national (or part national) grid.
The grid is not sized to carry late afternoon power from California to new York, even if it were linked.
If it were linked, energy would be wasted, as some grid current would travel to New York and back, cancelling out energy sent direct to e.g. Las Vegas.
However the main thrust of the argument is valid: The grid is not and never was designed to transport massive amounts of power from one end of the country to the other. It is easier and cheaper to build a power station where its needed.
In order to do that, it would need to be massively extended – a cost that the proponents of ‘green energy’ ignore.
The rule of thumb that I learned back when I did a lot of circuit board layouts, was that a signal would move through a trace at about 1 ft per nano-second. As clock speeds started pushing 100MHz, this started becoming a big deal.
What the speed would be in a copper or aluminum wire, I don’t know.
>That is why very long links tend to invert to HVDC, then revert to AC, as the Scandinavian/EU
>interconnectors do.
There are other reasons for DC links. The links between Germany and Scandinavia and Continental EU and UK are not long links. They are DC because
1. Many of these link are underwater cables. Water is polar, so an alternating electric field agitates water molecules and absorbs energy from the cables converting it to warmer water. There are ways around this, but making the link DC is both cheaper and more efficient.
2. Most of the regional interconnects in the US are connected by HVDC lines that are maybe 20 feet long. The reason is that, unlike an AC link, the two end do not need to be frequency and phase synchronized. Reducing the size of synchronized areas simplified operations and cleans up some ugly failure modes. In Europe, Scandinavia and Continental EU are separate grids each with its own phase synchronization. The DC links allow this phase and frequency separation.
The downsize is that, like the inverters on solar and wind generators, the DC links are poor at providing grid inertia or reactive power control.