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Renewable energy: words and their meaning

Right on the KDPV you see my car. With a consumption of 5 liters of diesel per hundred kilometers (actually a little less) and an average mileage of 16.7 thousand kilometers per year for Russia, it releases approximately 2.2 tons of carbon dioxide per year into the atmosphere (a liter of diesel forms 2.66 kg of carbon dioxide (.pdf) ) . The number of registered cars on the planet exceeded a billion . The burning of fossil fuels in private vehicles is considered one of the main causes of anthropogenic CO2 emissions.



On the left of the KDPV you can see my stove. The whole cold season, from autumn to spring, I drown it with wood. As WHO (.pdf) tells us , about three billion people on the planet use solid fuels for heating or cooking. For not the longest, because as the southern heating season I burn about fifteen cubic meters of firewood, emitting about 9 to 10 tons of carbon dioxide into the atmosphere *. Since firewood belongs to renewable biofuels, their heating is considered carbon-neutral and not contributing to anthropogenic emissions of CO 2 .
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* I did not find ready numbers for converting firewood to carbon dioxide, and in any case these are much less accurate values. However, based on the mass of cubic meters of wood and the mass fraction of carbon in the wood , the calculation of the amount of carbon dioxide is not particularly difficult.

- We know, we know! - you will say, - Wood carbon is involved in carbon cycles, regularly entering the atmosphere without assistance, and diesel fuel carbon from these cycles was quite long removed and buried deep underground, until we returned it to the atmosphere.

This wonderful argument does not take into account only one. The trees that I burn in the furnace this winter have grown for several decades. Next year winter will come again, and I will have to buy and burn the next fifteen cubic meters of firewood. And a year later will have to. And so every year. If this spring I, wanting to provide fuel for the future winters, plant seedlings, the trees that grew from them will cut down my sons for firewood: by the time, sadly, I have said goodbye to this world for a long time.

In other words, the characteristic turnover time of that part of the carbon cycle, which includes wood, is at least many decades. Experts of the United Nations, speaking about the danger threatening us, operate rather in the first tens of years. The difference in half order.
In a critical situation: and if we have only ten years left to act, then the situation is undoubtedly critical - a half-order difference seems to be a sufficiently serious reason for further reflection.

Let's be familiar: carbon footprint.

This is a relatively new concept, trying to introduce a single comparable indicator of damage to the natural environment, calculated as the amount of carbon dioxide emitted into the atmosphere. Like any single indicator, it is not overly good in details, but extremely convenient for evaluation and management purposes. It is also subject to all typical problems of common indicators (as a good example, we can consider disposable finances as a single indicator of the usefulness of a member of a society).

Without describing this concept in detail, we note that it may contain actions that do not lead to additional CO 2 emissions into the atmosphere, or even linking a certain amount of atmospheric carbon dioxide. The possibility of the existence of such actions directly implies the idea of ​​a carbon-neutral fuel, the use of which, once again, either does not lead to carbon dioxide emissions into the atmosphere, or, together with emissions, generates the processes of binding atmospheric CO 2 . In the framework of the carbon footprint concept, the use of such fuel, of course, should be fully encouraged.

Unfortunately, a significant part * of management decisions made in the field of carbon-neutral energy, can and should be attributed to an extensive class, commonly called profanity.

* Just in case, I will clarify. Under the noticeable part should be understood as “a noticeable part”, and not “the majority” or, all the more, “all”. I did not analyze all decisions on the management of renewable energy, but those that I criticize here are clearly visible. Including by results: cuttings are well seen on satellite images.

No, of course: national authorities and supranational organizations are calling for "taking urgent, unprecedented and large-scale measures" , as well as "to reduce carbon dioxide emissions by almost half by the year 2030 and reduce them to zero by the year 2050" .
Regular "British scientists" calculate carbon footprints even for sandwiches , making conclusions on the literal scale of the space.

And at the same time, the US Environmental Protection Agency (EPA) announces "a new decision on the carbon-neutrality of forest biomass )
The European Union issues a directive expressly calling for greater mobilization of existing timber reserves (To use the full potential of biomass ... assistance is needed to maximize the mobilization of existing timber reserves).

Well, and under our native aspens there is an active discussion of the issue of recognition as a renewable peat resource , the characteristic accumulation time of which is thousands of years.

What year do you say it is necessary to reduce emissions by half? ..

Good news from governments were immediately picked up by business. I quote without reference, on request “wood heating is carbon-neutral” you will find such a joy in quantity without my help.
Wood heating - a renewable energy source. We were the first in the market of fireplaces to calculate the carbon footprint of our fireplaces: the impact of the production and delivery of the fireplace to the customer can be leveled out in 1–2 years of operation. In this way, we help solve problems with the heating of homes and preserve the environment.
Indeed, if your business suddenly turned out to be useful to nature, this fact simply asks for a commercial!

In fact, under the flag of renewable energy development, we see another iteration of the destruction of natural ecosystems, this time not even for building materials, food and other cellulose, but simply for firewood.

What's happening?

Complementary to the carbon footprint concept is the idea of ​​carbon credits. It is quite simple: let's introduce a ceiling for carbon dioxide emissions. Anything higher than the ceiling will be subject to a fine - the underused quota can be sold to anyone who needs it. At the international level, the idea seems to have even taken root: if there is a product, there will also be buyers. For buyers catch up exchanges, futures contracts, derivatives, options ... well, you understand.

Essentially important point: the polluter pays, the source of the CO 2 emission. If the issue happened for a reason, and using carbon-neutral technologies, then it would not happen. And pay, it turns out, it seems, and not for that. Here it is, the driving belt of logging for firewood, now fashionably called “energy from biomass”, as well as persistent attempts to push through the same peat burning here.

Is it as good as it sounds?

Let's see what happens in the surrounding reality.

In terms of carbon balance, natural ecosystems are carbon stores, a huge carbon buffer that is in dynamic equilibrium with the environment. It is thanks to the dynamic equilibrium inherent in many chemical systems that the composition of the atmosphere is maintained constant with very good accuracy. Over the past few hundred years, the volume of this buffer has been significantly reduced by nature-reforming human activity, and continues to decrease with increasing speed.

Somewhat simpler, to assess the situation, all carbon on the planet can be divided into being in the atmosphere (in fact, also dissolved in the ocean, but it can be considered as a proportional part from the atmosphere) deposited and buried.
Buried is oil and coal, and carbonate layers of marine sediments. Without a specially applied external effort, he cannot return to biological cycles. Being in the atmosphere is also more or less clear.

The deposited carbon is currently bound in the organic matter of the biosphere. He did not cease to participate in whirlwinds, and he, undoubtedly, will return to the atmosphere: one question exactly when. The length of stay in the deposited form is highly variable. Thus, carbon dioxide, freshly bound by photosynthesis at the end of April, may return to the atmosphere after grass has fallen in early May. On the other hand, in non-chopped and unburned forest or in steppe black soil (where there are still steppes: there are already very few such places on the planet) fixed carbon can exist for more than one millennium, moving along trophic chains between different organisms. Well, for the extraction of carbon from the peat deposit, a geological cataclysm, even local, is required.

If 78% of nitrogen is believed to be inherited by the Earth from the abiogenic era, then the biosphere is fully responsible for the content of oxygen and carbon dioxide. For a time much longer than a person’s life, as a species, it controls the composition of the atmosphere with great accuracy. Strictly speaking, its responsibilities are not limited to the composition of the atmosphere, especially in terrestrial ecosystems, where vegetation cover ensures the availability and purity of fresh water, limits erosion, forms soil and so on. No animal or plant species in itself has such properties. To do this, I apologize for the allusion, a harmonious system of checks and balances, negative feedbacks and buffer elements.

Ecosystem.

Any ecosystem somehow interacts with the environment, exchanging with it flows of matter and consuming energy. As the initially lifeless territory is settled (this process is called succession and has a rather long series of stages), it accumulates a store of organic matter made up of so-called biomass and mortmass. These are fairly simple concepts: biomass is all that is part of living organisms; Mortmass, respectively, is an inanimate biogenic organic. Humus, forest litter, dry trunks and other peat. The ratio of biomass and mortmass can vary quite a lot: for example, in equatorial forests there is relatively little of it, the biota is very painful there, any dead organic matter is eaten up almost instantly. And in some peat bog the ratio will be reversed. But in both cases we are dealing with an accumulated stock of organic substances, thereby deposited carbon.

The process of accumulation of organic matter in an ecosystem is called production, and the substance itself is called production.

The extraction of carbon from the atmosphere is mainly engaged in green plants that use solar energy for this. All other members of the ecosystem use for life the energy of chemical bonds from plant-accumulated organic matter. The plants themselves, however, also spend part of the accumulated organic matter to maintain vital activity. The result of this process is the release of carbon dioxide into the atmosphere. This process is called breathing.

Very roughly the process of becoming an ecosystem can be divided into two stages. On the first, the ecosystem actively accumulates reserves of organic matter, the carbonic depot: on the second, it enters with dynamic equilibrium with the medium, including atmospheric carbon. The second stage is referred to as mature ecosystems, climax communities, and more; around the content of these terms and their meaning in botany, more copies were broken than was the case in Mamayeva, but the ecological essence does not change. And it consists in the equality of products with breathing. Binding carbon and return it to the atmosphere.

Here, on Habré, the argument about a dead tree is voiced from time to time, which, after decomposition, returns all bound carbon to the atmosphere. For a single tree, this (with a fair stretch: even a single tree will be eaten by wood-destroying fungi and insects, and will also contribute its share of organic matter to the soil) will be true. But for the forest, in which the hunters are very quickly located on any abandoned organic matter; Moreover, these hunters specialize in the extraction of specific forms of orphan organics - in general, this argument is incorrect for the forest. Only to achieve a climax in a community, at least several generations of trees should change in a natural way. But with his achievement still far from over.

The climax community, like any chemical system that is in dynamic equilibrium, interacts with the environment in complete agreement with the Le Chatelier principle known to us from chemistry: with external changes, equilibrium shifts towards compensating for these changes. In other words, with an increase in the concentration of CO 2 it will begin to more actively synthesize organics, depositing additional carbon into the bio and mortum. I did not find any estimates of this additional volume, but based on personal observations and general considerations + 10%, we can safely take it for a rather conservative value.
How effective can such compensation be?

Only in the forested area of ​​the Earth, which is about a third of the land area, is the amount of deposited organic matter calculated in terms of carbon dioxide a few trillion tons. It would seem that anthropogenic emission with its pitiful thirty billions on this background pales and is lost, fractions of a percent, the grain to the elephant. If it were not for the sad fact that there are not so many old communities close enough to equilibrium on the planet, and the area occupied by them continues to shrink. And earlier stages of development or restoration (actually, this is not the same thing) are characterized significantly, at least by an order of magnitude, by a smaller volume of carbonic depot, and not the first ones will be required to restore the previous volume even in the absence of the following violations. hundreds of years. Those very few generations of trees.

Moreover, in the extraction of wood, including for “carbon-neutral” heating, the forests that have already gone through a significant part of this long way are cut down, first of all.

Actually with a carbon trace in this place, there is also some slyness. In reality, after cutting down a natural or close-to-such forest, that very mature community: even if you take out and use all forest residues, there is a lot of organic matter left on the cutting area, which will not exist as an organic matter without an existing forest canopy. These are specific forest herbaceous plants, shade-tolerant and moisture-loving, these are mosses and other liverworts, finally, this is forest soil, devoid of ground cover, torn off by skidding, and rapidly oxidized by direct contact with the atmosphere.

Let's go back to the beginning. What is my seasonal heating, fifteen cubic meters of wood? This is about 0.1 hectares of average forest in the Non-Chernozem belt of Russia, and about six tons of dry wood. And only on one tenth hectare of such forest we will have tons of thirty biomass, and from ten to thirty mortmassy. Total forty to sixty tons of organic matter. Here it is, carbon depot, about which I speak.

Where is the difference? Since the natural cycles of organic recycling in this area are destroyed, and most of the forest biota cannot continue to exist without forest, most of them went on an emergency basis to replenish anthropogenic emission of carbon dioxide. Or is in the process of such a dispatch. Some more will be used in the process of post-forest restoration: ecosystems, of course, have restoration mechanisms. But this part, I dare to assure you, will not be excessively large.

By the way, such an oxidation of soil organic matter is characteristic of any exposed soil, for example, for a plowed field. The famous black soil burned in the first tens of years. I happened to visit one of those places where V.V. was a century before me. Dokuchaev described a layer of chernozem with a two-meter thickness. Limestone pieces, loam, ten centimeters of slightly humified layer. All it took was to plow up after the war, but to surpass the plan for handing over grain to the state. And two meters of chernozem are several thousand years of soil formation, and a minimum of a couple centners of carbon dioxide per square meter.

If you believe, for example, this textbook on the fundamentals of environmental economics, published in 2005, tropical forests are cut down at a speed of 13 million hectares per year. The Wikipedia article on deforestation provides a more cautious estimate of 6 million hectares per year, but it is stipulated that this estimate takes into account only official data from state forest management authorities. Approximately imagining the scale of unauthorized logging in the third world, I personally am ready to count thirteen million as a fairly balanced estimate.

Recalculating the biomass of deforested forests for carbon dioxide, we can assume that only in tropical forests annually carbon is removed from the carbon depot, which more than overlaps the annual difference between anthropogenic emissions and current carbon dioxide utilization. A rough (and, alas, accurate) estimate of the difference between the afforestation of the planet now and somewhere at the beginning of the Holocene gives us a delta of several trillion tons of potentially deposited carbon.

In this state of affairs, perhaps, even there is a perverse plus. In the purely fantastic version of the moratorium on logging and other environmental-destructive work for the next few centuries, we will not have to worry about the products of combustion of fossil fuels. Carbon depot planetary communities now, more than ever before in history, are far from full. They have been engaged in their consistent decrease for many centuries.

Of course, I'm not the only one so smart. When I selected materials for this article, at the request of a “wood burning carbon neutral”, it’s mostly not advertisements for fireplaces, but a harsh criticism of this approach: one , two , three and so on. Unfortunately, in Russian such materials are much smaller, and they are far from being occupied by the first pages of search engines.

The bottom line is that we have a simple conclusion. If you encourage wood heating, if you encourage switching to “environmentally friendly” paper packaging: in general, if you consider withdrawal of organic matter long-term accumulated in ecosystems as carbon-neutral, congratulations, you are a reptilian agent for whom the current climate of the Earth is known to be somewhat cold . Thus, anthropogenic emissions of CO 2 do not fight, so it can only be increased.

But there is this warming in reality, or not, what to do and who is to blame - this, as they say, is a completely different story, and strictly speaking, it’s not for me to tell.

PS I wrote this article for too long. Strictly speaking, the first, somewhat unfinished version appeared a year ago. The surrounding reality did not wait: in late December, a freshly accepted addition appeared on the website of the European Commission, the sustainability criteria adopted, if I understand correctly, at the December conference on energy and sustainable development.
- Biofuels cannot be grown in areas such as wetlands or forests.
- Biofuels cannot be produced from raw materials such as primary forests or highly biodiverse grasslands.
This is similar to an attempt to bring administration in minimal compliance with reality. Good news.

Let's look at further developments.

Source: https://habr.com/ru/post/434770/


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