Return to 350ppm: a mountain of tasks ahead

 

 

(Based on the recent paper Below Zero. Story also published on Medium.)

Atmospheric CO2 concentration is currently around 420 parts per million (ppm), far above the range of 180 ppm to 280 ppm during the last million years.

And it will continue to grow: even the fastest, most ambitious climate-optimal transition will increase CO2 concentration to at least 430 ppm. This is because we need energy for building renewable energy infrastructure, which has to be supplied by current fossil power during the transition. Any delays in building renewables will further increase atmospheric CO2 concentration and, thus, the risks of triggering a climate tipping cascade.

The ongoing anthropogenic geoengineering experiment of massive CO2 emissions into the atmosphere was not intended to heat the climate but to provide cheap and abundant energy. It, however, not only destabilizes the climate but also comes with a general feeling of human superiority, dominance, and detachment from the rest of nature. This additionally leads to mass extinction, resource exploitation, waste, and pollution. The experiment is failing catastrophically because the unintended side effects destabilize our life support system.

It is not yet too late to navigate back into a stable Earth system state.

However, this will require actions far beyond current political and societal ambitions. For stabilizing the climate in the long run, it is not only necessary to halt emissions, aiming to stay below 1.5°C heating. But it is furthermore inevitable to reduce radiative forcing to prevent triggering a tipping cascade. Reverting anthropogenic CO2 emissions is the most direct way of cleaning up our past damages, as it meddles with the carbon cycle we pushed out of balance in the first place. All other geoengineering proposals for radiative forcing management (for example, ocean fertilization, artificial aerosols, enhanced weathering, etc.) interfere with other Earth systems and geochemical cycles, thus bearing high risks for further unintended side effects.

We will need to remove all cumulative emissions since 1988: the point in time when atmospheric CO2 concentration first crossed 350 ppm, proposed as the safe long-term climate threshold. Restoring natural ecosystems is essential to taking up CO2, relieving the pressure on the biosphere, and changing our mindset. However, it will alone be insufficient to clean up our emissions in time. As most anthropogenic emissions had been released technically (power plants, car engines, aircrafts,…), most clean-up will also need to happen technically with below-zero emissions. Technologies for direct air capture and safe, permanent storage are emerging; we need to prepare them to scale up.

At least 400 Gt of pure carbon (i.e. 1500 Gt of CO2) must be permanently removed from the atmosphere. This is as much carbon as there had been concrete in use in society in 2015. In other words, all concrete structures — buildings, bridges, foundations, etc. — in use in 2015 weigh combined as much as the carbon we need to remove to stabilize the climate. If the phase-out of fossil burning is further delayed or we still think we can allow ourselves “hard-to-avoid” emissions, we will have to remove and store even more. To keep this already gargantuan task at a minimum, an immediate, fast, and complete transition to 100% renewable energy is vital!

To better illustrate the task ahead of us: Would we pile up 400 Gt carbon rubble in a cone (45° slope angle, ~1 t/m³ bulk density similar to coal)? It would be a mountain more than 7 000 m high. Mount Carbon of Anthropa, the human “continent”, would be the second highest among the now eight summits. And every day we wait, it will grow taller. I’m convinced we can rise to this challenge, and we will have to!

Setting the record straight on the EROI from renewables. It is much better than that of fossil fuels

From a recent paper by Murphy et al. 

The analysis performed herein represents a much-needed update and harmonization of the EROI literature, and it advances the conversation surrounding the viability of renewable resources in the energy transition process. A common argument is that the EROIs from renewable energy technologies are supposedly lower than those provided by fossil fuels, and that transitioning to RE technologies would therefore result in a large loss in net energy. The results of this analysis rebuke that sentiment, noting that the three most important technologies for the energy transition—wind, PV, and hydropower—all have EROIs at or above 10 (even when the output is weighted in terms of primary energy equivalent assuming a future-proof life-cycle grid efficiency of ηG = 0.7, i.e., 1 unit of electricity per 1.4 units of primary energy). This means that more than 90% of the energy produced by these technologies is delivered to society as net energy. 

Perhaps more interesting still, the EROIs from liquid fuels, including the EROI from conventional oil production, are less than 10 once the costs of refining and delivery to the point-of-use are included. Oil is widely considered the most important fuel for the economy, used mostly in the transportation sector. This means that oil delivers less net energy to society for each unit invested in extraction, refining, and delivery than PV or wind. The transition to electric vehicles, according to these results, will actually increase the amount of net energy delivered to society (even more so when considering the higher efficiency of electrical power trains vs. internal combustion engines). 

It is clear from these results that EROI estimates at the point of extraction can be wildly misleading. As a case in point, even if crude oil were measured to have an EROI of 1000 or more at the point of extraction, the corresponding EROI at the point of use, using global average data for the energy “cost” of the process chain, would still only be a maximum of 8.7. Furthermore, as the quality of oil, gas and coal continue to decline in the future, the energy “cost” of the associated process chains will increase, further reducing the EROIs. On the other hand, as the technologies used to harness renewable energy improve, the corresponding EROIs will continue to increase in the future.

The Growth of Photovoltaic Energy Continues!

 

Given the rapid advance of photovoltaic energy during the past few years, I think it is appropriate to repropose a post that I published some years ago on "Cassandra's Legacy" -- it was an easy prophecy to make, but it is a satisfaction to see that it is coming true. If we keep going at the current rate, in a couple of decades, fossil fuels will be memory, just like steam locomotives. 

From "Cassandra's Legacy"

Monday, August 15, 2016

Five billion years of energy supply: the "stereosphere" and the upcoming photovoltaic revolution

It seems to be popular nowadays to maintain that photovoltaic energy is just an "extension" of fossil energy and that it will fade away soon after we run out of fossils fuels. But photovoltaics is much more than just a spinoff of fossil energy, it is a major metabolic revolution in the ecosystem, potentially able to create a "stereosphere" analogous to the "biosphere" that could last as long as the remaining lifetime of the earth's ecosystem and possibly much more. Here are some reflections of mine, not meant to be the last word on the subject, but part of an ongoing study that I am performing. You can find more on a similar subject in a paper of mine on Biophysical Economics and Resource Quality, (BERQ)

"Life is nothing but an electron looking for a place to rest," is a sentence attributed to Albert Szent-Györgyi. It is true: the basis of organic life as we know it is the result of the energy flow generated by photosynthesis. Sunlight promotes an electron to a high energy state in the molecule of chlorophyll. Then, the excited electron comes to rest when a CO2 molecule reacts with hydrogen stripped away from an H2O molecule in order to form the organic molecules that are the basis of biological organisms. That includes replacing degraded chlorophyll molecules and the chloroplasts that contain them with new ones. The cycle is called "metabolism" and it has been going on for billions of years on the earth's surface. It will keep going as long as there is sunlight to power it and there are nutrients that can be extracted from the environment. 

But, if life means using light to excite an electron to a higher energy state, there follows that chlorophyll is not the only entity that can do that. In the figure at the beginning of this post, you see the solid state equivalent of a chlorophyll molecule: a silicon-based photovoltaic cell. It promotes an electron to a higher energy state; then this electron finds rest after having dissipated its potential by means of chemical reactions or physical processes. That includes using the potentials generated to manufacturing new photovoltaic cells and the related structures to replace the degraded ones. In analogy with the biological metabolism, we could call this process "solid state metabolism". Then, the similarities between the carbon-based metabolic chain and the silicon-based one are many. So much that we could coin the term "stereosphere" (from the Greek term meaning "solid.") as the solid-state equivalent of the well known "biosphere". Both the biosphere and the stereosphere use solar light as the energy potential necessary to keep the metabolic cycle going and they build-up metabolic structures using nutrients taken from the earth's surface environment.

The main nutrient for the biosphere is CO2, taken from the atmosphere, while the stereosphere consumes SiO2, taking it from the geosphere. Both metabolic chains use a variety of other nutrients: the stereosphere can reduce the oxides of metals such as aluminum, iron, and titanium, and use them as structural or functional elements in their metallic form; whereas the biosphere can only use carbon polymers. The biosphere stores information mostly in specialized carbon-based molecules called deoxyribonucleic acids (DNA). The stereosphere stores it mostly in silicon-based components called "transistors". Mechanical enactors are called "muscles" in the biosphere and are based on protein filaments that contract as a consequence of changing chemical potentials. The equivalent mechanical elements in the stereosphere are called "motors" and are based on the effects of magnetic fields on metallic elements. For each element of one of these systems, it is possible to find a functional equivalent of the other, even though their composition and mechanisms of operation are normally completely different.

A major difference in the two systems is that the biosphere is based on microscopic self-reproducing cells. The stereosphere, instead, has no recognizable cells and the smallest self-reproducing unit is something that could be defined as the "self-reproducing solar plant factory." A factory that can build not only solar plants but also new solar plant factories. Obviously, such an entity includes a variety of subsystems for mining, refining, transporting, processing, assembling, etc. and it has to be very large. Today, all these elements are embedded in the system called the "industrial system." (also definable as the "technosphere"). This system is powered, at present, mainly by fossil fuels but, in the future, it would be transformed into something fully powered by the dissipation of solar energy potentials. This is possible as long as the flow of energy generated by the system is as large or larger than the energy necessary to power the metabolic cycle. This requirement appears to be amply fulfilled by current photovoltaic technologies (and other renewable ones).

A crucial question for all metabolic processes is whether the supply of nutrients (i.e. minerals) can be maintained for a long time. About the biosphere, evidently, that's the case: the geological cycles that reform the necessary nutrients are part of the concept of "Gaia", the homeostatic system that has kept the biosphere alive for nearly four billion years. About the stereosphere, most of the necessary nutrients are abundant in the earth's crust (silicon and aluminum being the main ones) and easily recoverable and recyclable if sufficient energy is available. Of course, the stereosphere will also need other metals, several of which are rare in the earth's crust, but the same requirement has not prevented the biosphere from persisting for billions of years. The geosphere can recycle chemical elements by natural processes, provided that they are not consumed at an excessively fast rate. This is an obviously complex issue and we cannot exclude that the cost of recovering some rare element will turn out to be a fundamental obstacle to the diffusion of the stereosphere. At the same time, however, there is no evidence that this will be the case.

So, can the stereosphere expand on the earth's surface and become a large and long-lasting metabolic cycle? In principle, yes, but we should take into account a major obstacle that could prevent this evolution to occur. It is the "Allee effect" well known for the biosphere and that, by similarity, should be valid for the stereosphere as well. The idea of the Allee effect is that there exists  a minimum size for a biological population that allows it to be stable and recover from perturbations. Too few individuals may not have sufficient resources and reciprocal interactions to avoid extinction after a collapse. In the case of the stereosphere, the Allee effect means that there is a minimum size for the self-reproducing solar plant factory that will allow it to be self-sustaining and long-lasting. Have we reached the "tipping point" leading to this condition? At present, it is impossible to say, but we cannot exclude that it has been reached or that it will be reached before the depletion of fossil fuels will bring the collapse of the current industrial system.

The next question is whether a self-sustaining stereosphere can coexist with the organic biosphere. According to Gause's law, well known in biology, two different species cannot coexist in the same ecological niche; normally one of the two must go extinct or be marginalized. Solid state and photosynthetic systems are in competition with each other for solar light. There follows that the stereosphere could replace the biosphere if the efficiency of solid state transduction systems were to turn out higher than that of photosynthetic systems. But this is not obvious. PV cells today appear to be more efficient than photosynthetic plants in terms of the fraction of solar energy processed but we need to consider the whole life cycle of the systems and, at present, a reliable assessment is difficult. We should take into account, anyway, that solid state creatures don't need liquid water, don't need oxygen, are not limited to local nutrients, and can exist in a much wider range of temperatures than biological ones. It means that the stereosphere can expand to areas forbidden to the biosphere: dry deserts, mountaintops, polar deserts, and more. Silicon based creatures are also scarcely affected by ionizing radiation, so they can survive in space without problems. These considerations suggest that the stereosphere may occupy areas and volumes where it is not in direct competition with the biosphere.

The characteristics of the stereosphere also allow it the capability of surviving catastrophes that may deeply damage the biosphere and that will eventually cause its extinction. For instance, the stereosphere could survive an abrupt climate change (although not a "Venus Catastrophe" of the kind reported by James Hansen). Over the long run, in any case, the earth's biosphere is destined to be sterilized by the increasing intensity of the solar irradiation over times of the order of a billion years. (and smaller for multicellular organisms). The stereosphere would not be affected by this effect and could continue existing for the five billion of years in which the sun will remain in the main sequence. Possibly, it could persist for much longer, even after the complex transformations that would lead the sun to become a white dwarf. A white dwarf could, actually power PV systems perhaps for a trillion years!

A more detailed set of considerations of mine on a related subject can be found in this article on "Biophysical Economics and Resource Quality, BERQ). 

Notes: 

1. I am not discussing here whether the possible emergence of the stereosphere is a good or a bad thing from the viewpoint of humankind. It could give us billions of years of prosperity or lead us to rapid extinction. It seems unlikely, anyway, that humans will choose whether they want to have it or not on the basis of rational arguments while they still have the power to decide something on the matter. 

2. The concept of a terrestrial metabolic system called the stereosphere is not equivalent, and probably not even similar, to the idea of the "technological singularity" which supposes a very fast increase of artificial intelligence. The "self-reproducing solar plant factory" needs not be more intelligent than a bacterium; it just needs to store a blueprint of itself and instructions about replication. Intelligence is not necessarily useful for survival, as humans may well discover to their chagrin in the near future.

3. About the possibility of a photovoltaic-powered Dyson sphere around a white dwarf, see this article by Ibrahim Semiz and Salim O˘gur.

4. The idea of "silicon-based life" was popularized perhaps for the first time by Stanley Weinbaum who proposed his "Pyramid Monster" in his short story "A Martian Odissey" published in 1933. Weinbaum's clumsy monster could not exist in the real universe, but it was a remarkable insight, nevertheless. 

A Christmas Post: The Miracle of Renewables

by Ugo Bardi

This is a post that I wrote for the Italian newspaper "Il Fatto Quotidiano." For this reason, it is simplified and short, yet it says what's needed to understand the revolution we are going through that will change the world in the coming years. If you are interested in the source of the data on which I am basing my considerations, you can find them on Lazard.com. So, Merry Christmas, and never despair. Sometimes, miracles happen! 

Miracles are not so frequent and, if one has serious health problems, it is not probable that a swim in the Lourdes pool will solve them. However, it is also true that sometimes things change quickly, opening up new possibilities. That's what's happening with renewable energy. Talking about a "miracle" is a bit much, I know, but recent technological developments have made available to us a tool that until a few years ago we didn't even dream of having. And this could solve problems that once seemed unsolvable.

For years, I've been lecturing about climate change and other looming worries, such as oil depletion. Usually, the people who came to listen to me were prepared for a message that was not exactly reassuring, but the question was what to do about it. At the end of the conference, a debate normally ensued in which the same things were said: ride a bicycle, turn down the thermostat in the house, install double glazing panes on the windows, use low energy light bulbs, things like that.

It was a little soothing ritual but, in reality, everyone knew that these weren't real solutions. Not that they're useless, but they're just a light layer of green on a system that continues to depend on fossil fuels to function. We have been talking about double glazing and bicycles for at least twenty years, but CO2 emissions continue to increase as before. Actually, faster than before. If we don't go to the heart of the problem, which is to eliminate fossil fuels, we will get nowhere. But how to do it? Until a few years ago, there seemed to be no way except to go back to tilling the fields by hand, as our ancestors did during the Middle Ages.

But today things have changed radically. You probably didn't notice it, caught up in the debate on politics. But it doesn't matter whether the right or the left wins. Change, the real one, is coming with renewable technologies. Wind and photovoltaic plants have been optimized and scaling factors have generated massive savings in production costs. Today, a kilowatt-hour produced by a photovoltaic panel costs perhaps a factor of 5-10 less than a kilowatt-hour from natural gas (and maybe a factor of 5 less than a nuclear kilowatt-hour) (source). We used to call renewables "alternative energy," but today all others are "alternative."

Furthermore, producing energy with modern renewable technologies does not pollute, does not require non-recyclable materials, does not generate greenhouse gases, does not generate local pollution, and nobody can bomb the sun to leave us without energy. Now, don't make me say that renewables have automatically solved all the problems we have. It is true that today they are cheap, but it is also true that they are not free. Then, investments are needed to adapt energy infrastructure throughout the country, to create energy storage systems, and much more. These are not things that can be done in a month, or even in a few years. There is talk of a decade, at least, to arrive at an energy system based mainly on renewables.

But it is also true that every journey begins with the first step. And now we see ahead of us a road ahead. A road that leads us to a cleaner, more prosperous, and hopefully less violent world. I haven't stopped going around giving conferences but, now, I can propose real solutions. And it's not just me who noticed the change. In the debate, today you can feel the enthusiasm of being able to do something concrete. Many people ask if they can install solar panels at home. Others say they've already done it. Some mad (and rightfully so) at the bureaucracy that prevents them from installing panels on their roof or in their garden. You see the changed trend also on social media.

There is always someone who speaks out against renewables reasoning like the medieval flagellants who went around shouting "remember that you must die". But there are also those who respond in kind, like, "good riddance, live happily in your cave together with the other cavemen." If you have a south-facing balcony (and if your municipality doesn't sabotage your idea), you can already install photovoltaic panels hanging from the railing that will help you reduce your electricity bill. No paperwork needed! (another small miracle). One step at a time, we will succeed!

Flash Gordon's Revenge: the Campaign for Small Wind Turbines

 

By Ugo Bardi

We are seeing the development of a small (or maybe not even so small) PR campaign designed to convince people that small wind turbines are better than PV panels. It goes (or should go) without saying that these turbines are much less efficient than PV panels, they are expensive, unreliable, noisy, require maintenance, and - about the fact that they are "silent" wait a few years to hear the noise of the worn out ball bearings. And let's skip the description of what could happen if they are hit by a serious gust of wind. The one above is especially clunky, it looks like Flash Gordon's spaceship. Fortunately, it seems to be just a rendering of something that doesn't exist in practice.

It is, likely, a rear-guard battle of the fossil lobby to try to slow down the diffusion of photovoltaics. Unfortunately, some people seem to believe that these micro-turbines are useful for something. It shall pass, but, as usual, it will take some time.

https://www.informacion.es/medio-ambiente/2022/12/06/liam-f1-pequeno-silencioso-aerogenerador-79633542.html