California Rooftop Revolution

Clawing back benefits for rooftop solar proves politically and programmatically perilous.

California is a leader in fighting climate change. You just have to look at a trace of an average day's electrical power sources to see what is going on:

One day in the life of the California electricity grid. Solar dominates during the day, but fossil fuels are still used heavily. Imports from other states are a mix of solar, nuclear, and fossil fuel sources, even some coal.

Solar power now dominates electricity production during mid-day periods. California has 1.5 million solar roof installations, (supplying 12 GW of capacity), which are, however, dwarfed by utility scale solar of about 24 GW in huge desert arrays. California doesn't have the kind of wind power that Texas and the Midwest have, but we have gone all in for solar, which supplies one fourth of our electricity.

But we are only beginning to reshape the grid. Addressing climate change means getting to zero fossil fuel use. In the graph above, you can see that, even at mid-day, we have natural gas plants humming along, supplying one third of electrical needs. It is the most efficient natural gas power plants (combined cycle) which can not be used as peaker plants, but need to be on full time, more or less, ironically. And then we have a huge fleet of peaker plants (and imported power from those in other states) to provide the mad rush of power required to transition every night from daytime solar to evening. The daily peak of power use comes not at noon, but at 6 PM. On top of this, decarbonizing transportation and heating/HVAC of buildings requires further electrical loads to be added to the grid, not all at convenient times.

California utilities are not state-run, but are heavily regulated. For instance, they make no profit from retail electricity sales, but from grid maintenance and power plant provision, via "decoupling" rules. The California Public Utilities Commission (CPUC) is the regulator, and has the job of planning this enormous transition. One of its biggest headaches is what to do about rooftop solar. Back in 2006, the state set its million solar roofs initiative, with the central component being net metering, or NEM. This said that retail customers get the same rate paid to them for electricity sent into the grid by their solar panels as they pay for electricity they take out of the grid. Back then, with solar barely viable and a tiny proportion of production, this subsidy made a lot of sense. And the program became increasingly attractive as solar costs came down.

But today, NEM is less economical. Solar customers make up 11.5% of total households, an increasingly significant share of the utility customer base. Solar power at mid-day is decreasingly valuable to the grid, failing to relieve the real crunch that happens into the evening. The lost revenue represents not only money for electrical generation, but for grid services and maintenance, which solar households make particularly significant use of, as the grid is essentially their battery and longer-term backup. And who pays the freight? The other rate payers, who on average are less rich than those who can foot the bill for solar. Extrapolating to all residences having solar power, the utilities would no longer have anyone paying for the system, at all. The CPUC made a proposal in 2021, inspired by these imbalances (not to mention the loathing utilities have for NEM), to drastically cut rates paid for exported solar energy, and also charge a grid connection fee of roughly $60 per month for solar households. 

This caused a firestorm, needless to say. In the proud American tradition of the powerful rebelling against any reduction of their ill-gotten gains or structural advantages, the proposal was mercilessly attacked in the press, and the governor forced the CPUC to go back to the drawing board. While the policy was indeed bad and would have destroyed the rooftop solar industry, the reaction was reminiscent of the Prop 13 "revolution", where property owners relieved themselves of taxes, or even the Boston tea party and American Revolution, where taxes meant to maintain the colonies were declared abhorrent impositions, later to be replaced by the far more ruinous costs of war and independence. 

In the newest iteration, just released, the CPUC follows the Prop 13 blueprint and grandfathers in all existing solar installations, selling only future installations down the river of reduced payback rates. It also drops the particularly galling grid connection fee, which was, in a policy sense, entirely appropriate. Someone needs to pay for the grid, after all. For my part, I would support a new grid electricity rate, charged on both import and export of energy. That way, solar users would be charged for the outgoing loads they put on the system, and encouraged to install (and use) batteries to reduce all loads on the grid. Extrapolated to universal participation, this would, instead of killing the grid by underfunding, make it smaller, as a backup resource, with funding aligned with usage.

Anyhow, in a masterful show of bureaucratic obfuscation, the CPUC in its newest proposal sets the future payback rate of solar to be a mysterious function of overall costs and climate impacts over a regional and hourly basis through the year- called the avoided cost calculator, or ACC. From the simplicity of NEM, we now go to a system that is both impenetrable and unpredictable, since the yearly calculations have been wildly varying, and result from a byzantine mechanism that takes 100 pages to explain.

How the ACC was set in three recent years. The variability is evident.

This seems like a case of the road to hell being paved with good intentions. It makes sense (in an ideal economic world) to relate the payback rate of exported solar power to the actual value of that power. The wholesale electricity market deals in such rates on a minute-to-minute basis. But the solar installation industry relies on predictability- the predictability of solar power coming out of solar panels for twenty or more years, and the predictability of its value, which was so neatly supplied by the NEM concept. This variable pricing proposal might be as dangerous for the rooftop solar industry as the grid connection fee was going to be. 

That may have been the plan, I don't know. But the CPUC needs to figure out what it wants at a deeper level. We can grant that on a global basis, residential rooftop solar is a relatively inefficient way to supply electricity and fight climate change. It is roughly 30% more expensive than utility-built mass solar installations. In compensation, the distributed nature of residential solar lowers the typical grid load, evens out production, and supplies important backup capability to customers, when paired with battery storage. Battery storage is something the CPUC aims to make default for solar installations, by using differential rates to offer low rates for electricity export at peak solar times, and paying much higher (if unknown!) rates at peak grid demand and demand growth times. The need to stabilize the grid and get rid of all those natural gas peaker plants is palpable. The CPUC plans for a future of utility scale battery installations that will provide that time-of-day balancing.

The California climate plan- how will we get there?

The key problem is that the state (and CPUC) plan is to grow residential solar, almost doubling penetration over the next decade, and more than tripling over the longer term. The combination of ever-expanding grid scale to electrify the state plus decarbonization means that everything needs to be pursued- utility scale, residential, and storage, all as fast as possible. That is not going to happen with reduced incentives and greater uncertainty for the residential solar sector. After all, the whole regulatory mechanism exists to not to precisely calibrate the lowest cost source of power- markets can do that. It exists to shift costs around, so that the future (and externalized) catastrophic planetary, social, and economic costs of climate change can be brought forward to influence today's choices. 

So there is a solution to this mess, which is to tax fossil fuels at much higher rates. Rather than fighting over marginal solar export rates and which kind of solar installation is better for the grid, we need to assess costs where the real costs lie- at the fossil fuels that are poisoning the biosphere and keeping us from a sustainable future. Since the CPUC is in control of the economics of electricity in the state, it should turn its formidable bureaucratic skills (in collaboration with the other entities that are in charge of fuel taxation, principally the legislature), in a more useful direction, such as raising the costs of the fuels we don't want while lowering those we do. That might mean charging a climate mitigation fee over all fossil fuels (beyond the very modest cap and trade fee California already participates in) that would pay for a moderated NEM bonus for residential solar, plus the batteries, grid strengthening, and everything else needed to put us on a deeper decarbonization path. Raising rates for electricity overall while redistributing prices in this way to favor clean energy would be difficult to sell, but quite justifiable. Especially if it did not penalize electricity use over the direct use of fossil fuels for heating and transportation, by taxing those fuels uniformly.

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Skype for Cells, and Valves for Mitochondria

Connexin is one of those proteins that get more roles the harder people look.

One reason genetics is hard is that genetic products (proteins, generally) can have complicated roles in the organism- i.e. phenotype. For every simple case like sickle cell anemia, there are ten complicated cases where mutations are covered by duplicative functions, or have effects only revealed under unusual circumstances, or have multiple effects that are hard to connect and understand. Today's post focuses on a protein called connexin, which joins up into hexameric (6-member) complexes to form membrane half-channels, or hemichannels. When two such hemichannels on neighboring cells meet up, then join to form a gap junction, which is a small pore, permeable to molecules up to about 1000 Daltons. So ions, water, hormones, and other small molecules get through, but not most proteins or nucleic acids. They also help align the electrical charge or electrical propagation of neighboring cells. These junctions are surprisingly common in our bodies, functioning a bit like Skype, keeping neighboring cells in close touch. They have big roles in development, adhesion, neuron activity, and even cancer. Cancer cells tend to turn their gap junctions off in order to go their own way.

Structures of some connexin complexes, as hemichannels (below), and as full gap junctions (above).  "In" denotes inside each cell, "Ex" denotes the extra-cellular space, and the lipid bilayer would be the plasma membrane in this normal case.

But recent work has shown that hemichannels by themselves have regulated conductance properties and a variety of roles, some of which do not even rely on their channel properties. One recent paper (though with precedent work going back to 2006) raised the prospect of connexin hemichannels functioning in mitochondria, on the inner membrane, as regulated potassium channels. The mitochondrial inner membrane is notoriously impermeable, in order to accumlate the proton-motive force (pmf), which is the product of respiration / catabolism of food, and used for the synthesis of ATP. Protons are pumped out of the innermost mitochondrial matrix and into the inter-membrane space, setting up a pH and charge gradient, usable as energy. The ultimate concentration of hydrogen is not terribly high, however, and the overall ionic (and osmotic) balance remains governed by more conventional gradients of ions like sodium, potassium, and chloride. Thus it is important to regulate those balances using channels that are specific for those ions and don't conduct (i.e. leak) protons. 

Aside from the connexin channel discussed here, there are numerous other potassium conducting channels in the mitochondrial inner membrane, with individual regulation.

For potassium, there are at least seven channels now known, each regulated differently. That is amazing, really, for a membrane that should be so impermeable, though most are present at low levels. There is a K+/H+ antiporter that extrudes K+ to maintain osmotic balance, and then the other channels are all leakage channels that allow K+ back in, under various regulated conditions. The logic seems to be that the electron transport chains of respiration can easily run too "hot", giving off poisonous reactive oxygen species like peroxide, instead of the coordinated O2 reduction to water and proton export, as intended. So the major transport chain stations appear to have associated potassium channels that are inducible by reactive oxygen species, among other things, in order to fine-tune the local membrane potential and respiration rate. It seems like a curious way to run things, reducing the efficiency of a system that would be better inhibited earlier in the respiration process. 

Another model is that the fine-tuning by these channels forestalls the more catastrophic activation of PTP channels (mitochondrial permeability transition pore). These are more like gap junctions, totally non-discriminating in their channel characteristics, and are induced by high levels of stress from reactive oxygen species. When induced, these can totally leak away the protonmotive force, and if sustained, can kill the mitochondrion and even the whole cell. This would lead to what the current researchers found, which was that genetic reduction of the levels of the connexin Cx43 caused all kinds of bad outcomes in cells treated with peroxide, such as lower proton motive force, lower electron transport chain coupling, and lower ATP production.

ATP production is raised by leaking K+ into the mitochondrial matrix, and lowered conversely by reduction of connexin levels. "CxKD" denotes a genetic knock-down, or reduced expression, of the Cx43 connexin protein. They note, however, that expression of one ATP synthase component is reduced as well in this setting, so there may be yet other (gene regulation) effects going on here.

 

At any rate, the finding that one connexin that participates in cell surface gap junctions, called Cx43, is also specifically transported to the inner membrane of mitochondria during reactive oxygen species stress, (a stress that has very wide-ranging occurrence and effects, at the cellular and organismal levels, not just in mitochondria), and then acts there as a regulated K+ leakage channel, is quite unexpected. While the gap junction is a promiscious, wide channel, this activity must be far more discriminating. Add to that that it associates specifically with the H+ consuming ATP synthase, at the matrix side of the inner mitochondrial membrane, and we have a protein with a double life.

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The Politics of Resentment

Ann Applebaum has seen where all this Trumpism is going ... in Eastern Europe.

Liberals in America are baffled. How could anyone vote for Republican candidates at this point? How could anyone, let alone half the electorate, vote for Trump? We are befuddled and anxious for the future of America, which, far from becoming great again, is turning into a banana republic before our eyes, if, hopefully, not worse. We in California are particularly dissociated, as Democrats run the whole state, and Republican voter registration continues to decline year after year and is now under one quarter of the electorate. What does the rest of the country see that we do not? Or vice versa?

Ann Applebaum has written a trenchant book on the matter, "Twilight of Democracy". She lives in Poland, so has had a front-row seat to the illiberalization of a political system, both in Poland and in nearby Hungary, which seems farther advanced. Eastern Europe has more reason than most, perhaps to be disillusioned with the capitalist orthodoxy, after their rather rough transition from Communism. But this is a world-wide phenomenon, sweeping fringe rightists into power from Brazil to Sweden. What is going on? Applebaum posits that the whole structure of meritocratic representative democracy, with its open competition for (good) public policy, and use of educated expertise over vast areas of state interests from foreign affairs to monetary regulation and education policy, have come under fundamental critique. And this critique comes partly from those who have been shut out of that system: the not-well-educated, not-bicoastal, not-rich, not-acronymed-minority, not-hopeful about the American future. It is, in short, a politics of resentment.

How have the elites done over the post-world war 2 period? They won the cold war, but lost virtually every battle in it, from Vietnam to Afghanistan. They let the lower classes of the US sink into relative poverty and powerlessness vs business and the well-educated classes, in a rather brutal system of collegiate competition, de-unionization, off-shoring and worker suppression. They have let the economy fester through several crushing recessions, particularly the malaise of the 70's and the real estate meltdown of 2008. While the US has done pretty well overall, the lower middle and poor classes have not done well, and live increasingly precarious lives that stare homelessness in the face daily. In the heartland, parents at best saw their children fly off to coastal schools and cultures, becoming different people who would not dream of coming home again to live.

America is heavily red, geographically.

And the elite-run state has become increasingly sclerotic, continually self-criticizing and regulating its way to inaction. A thousand well-meaning regulations have paved the way to a bloated government that can not build a high-speed rail line in California, or solve the homelessness crisis. Everyone is a critic, including yours truly- it is always easier to raise objections, cover one's ass, and not get anything done. So one can sympathize with evident, if inchoate, desires for strength- for someone to break the barriers, bring the system to heel, and build that wall. Or get Brexit done. Or whatever the baying right wing media want at the moment.

The elite party in this sense is the Democratic party - capturing the coastal and well-educated, plus public employee unions. The Republican party, the party of money and the rich, (not the elite at all!), has conversely become the party of the downtrodden, feeding them anti-immigrant, anti-elite, anti-state red meat. It was a remarkably easy transformation, that required only shamelessness and lying to make hay out of the vast reserves of resentment seething in middle America. 

But Applebaum's point is not that the elites have messed things up and it may be time to do things differently. No, she suggests that the new protofascists have reframed the situation fundamentally. The elites in power have, through the hard work of meritocratic institutions, set up pipelines and cultures that reproduce their position in power almost as hermetically as the ancien régime of France and its nobility. That anyone can (theoretically) enter this elite and that it is at least somewhat vetted for competence and rationality is disregarded, or actively spat upon as "old" thinking- definitely not team thinking. The path to power now is to stoke resentment, overturn the old patterns of respect for competence and empathy, discard this meritocratic system in favor of one based on loyalty and fealty, and so bring about a new authoritarianism that brooks no "softness", exercises no self-criticism, has no respect for the enemy or for compromise, and has no room for intellectuals. 

But Hungary is way ahead of us, in the one-party rule department.

A second angle on all this is that conservatives feel resentful for another good reason- that they have lost the culture war. Despite all their formal power, winning the presidency easily half the time, and regularly running legislative branches and judicial branches in the US, their larger cultural project to keep progress at bay, fight moral "decadence" and all the other hobby horses, have gone nowhere. The US is increasingly woke, diverse, and cosmopolitan, and the "blood and soil" types (including especially conservative Catholics and Evangelicals), are despondent about it. Or apoplectic, or rabid, etc., depending on temperament. Their triumph in overturning Roe may allow some backwater states to turn back the clock, but on the whole, it looks like a rearguard action.

This is what feeds disgust with the system, and with democracy itself. Republicans who used to sing the praises of the US government, the flag, and democracy now seem to feel the opposite, that the US is a degenerate wasteland, no better than other countries, not exceptional, not dedicated to serious ideals that others should also aspire to. Democracy has failed, for them. And Applebaum points out how this feeling licenses the loss of civility, the lying, the anything-goes demagoguery which characterizes our new right-wing politics. Naturally the internet and its extremism-feeding algorithms have a lot to do with it as well. Applebaum is conservative herself. She spent a career working in the Tory media in Britain, but is outraged at what Tory-ism, and conservatism internationally, has become. She sees a dramatic split in conservatism, between those that still buy into the democratic, liberal system, and those who have become its opponents, in their revolutionary, Trumpy fervor. In the US, the fever may possibly have broken, after a very close brush with losing our institutions during the last administration, as election after election has made losers of the far right.

Over the long haul, Applebaum sees this as a cyclical process, with ample precedent from ancient Egyptian times through today, with a particularly interesting stop in the viciously polarized Drefussard period in France. But I see one extra element, which is our planetary and population crisis. We had very good times over the last few centuries building the human population and its comforts on the back of colonization, fossil fuels, and new technologies. The US of the mid to late-20th century exemplified the good times of such growth. Now the ecological bells are ringing, and the party is coming to an end. Denial has obviously been the first resort of the change-averse, and conservatives have distinguished themselves in their capabilities in that department. But as reality gradually sets in, something more sinister and competitive may be in the offing, as exemplified by the slogan "America First". Not first as in a leader of international institutions, liberal democracies and enlightenment values, but first as in looking out for number one, and devil take the rest. 

Combined with a rejuvinated blood and soil nationalism, which we see flourishing in so many places, these attitudes threaten to send us back into a world resembling that before world war 1 or 2, (and, frankly, all the rest of history), when nationalism was the coin of international relations, and national competition knew no boundaries- mercantile or military. We are getting a small foretaste of this in Russia's war on Ukraine, which is a product of precisely this Russia-first, make Russia great again mind-set. Thankfully, it is accompanied by large helpings of stupidity and mismanagement, which may save us yet. 

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LPS: Bacterial Shield and Weapon

Some special properties of the super-antigen lipopolysaccharide.

Bacteria don't have it easy in their tiny Brownian world. While we have evolved large size and cleverness, they have evolved miracles of chemistry and miniaturization. One of the key classifications of bacteria is between Gram positive and negative, which refers to the Gram stain. This chemical stains the peptidoglycan layer of all bacteria, which is their "cell wall", wrapped around the cell membrane and providing structural support against osmotic pressure. For many bacteria, a heavy layer of peptidoglycan is all they have on the outside, and they stain strongly with the Gram stain. But other bacteria, like the paradigmatic E. coli, stain weakly, because they have a thin layer of peptidoglycan, outside of which is another membrane, the outer membrane (OM, whereas the inner membrane is abbreviated IM).

Structure of the core of LPS, not showing the further "poly" saccharide tails that would go upwards, hitched to the red sugars. At bottom are the lipid tails that form a strong membrane barrier. These, plus the blue sugar core, form the lipid-A structure that is highly antigenic.

This outer membrane doesn't do much osmotic regulation or active nutrient trafficking, but it does face the outside world, and for that, Gram-negative bacteria have developed a peculiar membrane component called lipopolysaccharide, or LPS for short. The outer membrane is assymetric, with normal phospholipids used for the inner leaflet, and LPS used for the outside leaflet. Maintaining such assymetry is not easy, requiring special "flippases" that know which side is which and continually send the right lipid type to its correct side. LPS is totally different from other membrane lipids, using a two-sugar core to hang six lipid tails (a structure called lipid-A), which is then decorated with chains of additional sugars (the polysaccharide part) going off in the other direction, towards the outside world.

The long, strange trip that LPS takes to its destination. Synthesis starts on the inner leaflet of the inner membrane, at the cytoplasm of the bacterial cell. The lipid-A core is then flipped over to the outer leaflet, where extra sugar units are added, sometimes in great profusion. Then a train of proteins (Lpt-A,B,C,D,E,D) extract the enormous LPS molecule out of the inner membrane, ferry it through the periplasm, through the peptidoglycan layer, and through to the outer leaflet of the outer membrane.

A recent paper provided the structural explanation behind one transporter, LptDE, from Neisseria gonerrhoeae. This is the protein that receives LPS from a its synthesis inside the cell, after prior transport through the inner membrane and inter-membrane space (including the peptidoglycan layer), and places LPS on the outer leaflet of the outer membrane. It is an enormous barrel, with a dynamic crack in its side where LPS can squeeze out, to the right location. It is a structure that explains neatly how directionality can be imposed on this transport, which is driven by ATP hydrolysis (by LtpB) at the inner membrane, that loads a sequence of transporters sending LPS outward.

Some structures of LptD (teal or red), and LPS (teal, lower) with LptE (yellow), an accessory protein that loads LPS into LptD. This structure is on the outer leaflet of the outer membrane, and releases LPS (bottom center) through its "lateral gate" into the right position to join other LPS molecules on the outer leaflet.

LPS shields Gram-negative bacteria from outside attack, particularly from antibiotics and antimicrobial peptides. These are molecules made by all sorts of organisms, from other bacteria to ourselves. The peptides typically insert themselves into bacterial membranes, assemble into pores, and kill the cell. LPS is resistant to this kind of attack, due to its different structure from normal phospholipids that have only two lipid tails each. Additionally, the large, charged sugar decorations outside fend off large hydrophobic compounds. LPS can be (and is) altered in many additional ways by chemical modifications, changes to the sugar decorations, extra lipid attachments, etc. to fend off newly evolved attacks. Thus LPS is the result of a slow motion arms race, and differs in its detailed composition between different species of bacteria. One way that LPS can be further modified is with extra hydrophobic groups such as lipids, to allow the bacteria to clump together into biofilms. These are increasingly understood as a key mode of pathogenesis that allow bacteria to both physically stick around in very dangerous places (such as catheters), and also form a further protective shield against attack, such as by antibiotics or whatever else their host throws at them.

In any case, the lipid-A core has been staunchly retained through evolution and forms a super-antigen that organisms such as ourselves have evolved to sense at incredibly low levels. We encode a small protein, called LY96 (or MD-2), that binds the lipid-A portion of LPS very specifically at infinitesimal concentrations, complexes with cell surface receptor TLR4, and sets off alarm bells through the immune system. Indeed, this chemical was originally called "endotoxin", because cholera bacteria, even after being killed, caused an enormous and toxic immune response- a response that was later, through painstaking purification and testing, isolated to the lipid-A molecule.

LPS (in red) as it is bound and recognized by human protein MD-2 (LY96) and its complex partner TLR4. TLR4 is one of our key immune system alarm bells, detecting LPS at picomolar levels. 

LPS is the kind of antigen that is usually great to detect with high sensitivity- we don't even notice that our immune system has found, moved in, and resoved all sorts of minor infections. But if bacteria gain a foothold in the body and pump out a lot of this antigen, the result can be overwhelmingly different- cytokine storm, septic shock, and death. Rats and mice, for instance, have a fraction of our sensitivity to LPS, sparing them from systemic breakdown from common exposures brought on by their rather more gritty lifestyles.

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