Whether driven by high energy costs or the fight against climate change, the energy transitioning seems to be an increasingly polarizing topic. Although there have always been skeptics, switching to renewable energy sources (and avoiding nuclear power) is currently the "politically correct" position.

The environmental mantras: "All you have to do is a U-turn!" or "We promote the installation of solar panels!" or "We must expedite the construction of wind farms!" are all still unbelievably ignorant. There also seems to be a great deal of confusion about the place of climate change in the big picture, and whether it is a crisis or not.

The possibility of a global green revolution

In people's imagination, the future society's energy source is something safe, clean and infinite. Perhaps sustainable. At first glance, "renewable energy" seems to be a suitable and attractive candidate, consisting primarily of natural manifestations of solar energy (light, heat, wind, water, biomass.) It should be added, however, that most of these energy flows are gentle enough for living organisms to survive in them (hence "clean" and "safe.") This reality, however, casts doubt on renewable energy's capacity to sustain industrial civilization.

Approximately 10,000 times more solar energy falls on the surface of the Earth than is consumed by humanity. As long as we do not attempt to study the energy loss that occurs during the transmission of energy to the final user and the resulting ecological footprint in greater depth, capturing this 1/10,000 seems quite simple.

Musk (founder and CEO of Tesla and SpaceX) has described repeatedly in his talks how "easy" the shift to renewable energy could be: simply stack 200×200 km² of 20 percent efficiency solar panels (plus a few square kilometers of lithium batteries) in a desert, and the United States would have its entire energy supply. This claim is not entirely false, as the average annual energy production of such a solar farm would be comparable to the United States' annual energy demand.

On a similar level of superficiality, we should mention that such a structure would be inexpensive because the earth's crust contains an abundance of all the necessary (and not particularly rare) chemical elements. A more realistic assessment of the possibility of a green revolution, on the other hand, is a real issue.

For example, English physicist David MacKay attempted to do just this in his book "Sustainable Energy - Without the Hot Air" more than a decade ago.
Taking such a detailed approach in this article, however, risks drowning the reader in numbers, as the potential for renewable energy varies widely across different types and locations. So let's keep this analysis as simple as possible.

Therefore, our initial energy store spans four magnitudes. Let's reserve one percent of the planet's surface for solar and wind farms (because 10 percent would be ecologically disastrous.) With that we quickly lose two orders of magnitudes of energy. Even with solar panels with a 20 percent efficiency, it is practically impossible to convert more than 10 percent of primary energy into electricity, resulting in a further loss of an order of magnitude.

The efficiency of energy storage, conversion (e.g., to liquid fuels,) and transport (line losses, etc,) as well as the development, maintenance and disposal of all infrastructure, should be counted in as all the activities where energy is lost (before reaching the final user.) We barely had a magnitude's worth of energy reserve, and I'm not even certain that this final number will be positive.

The problem is not improved by the fact that the global energy demand is still on a steep rise. To create twice as much electricity, for example, twice as many solar panels or wind turbines would need to be constructed, which would require twice as much land (there will be some efficiency gains from technological progress over time, but these are marginal.)

Tech-savvy people are often overly optimistic about the potential of a green revolution. Elon Musk's thinking experiment has already been mentioned. Another frequently cited fact is that the price of solar panels, wind turbines and (to a lesser extent) batteries has decreased dramatically over the past few decades. It is possible that the cost per unit of nominal (or even actual average) capacity is less than that of fossil and nuclear energy. (Given the political marginalization of fossil and nuclear power, and the fact that solar and wind components are manufactured in China using the cheapest coal power and slave labor, this may not be surprising.) 

However, it is critical to understand that solar panels and wind turbines are only primary energy receivers. So let's get to the point where they cost nothing. The real challenge in this case is determining whether there is enough space to install them (which, of course, must be stolen from nature, as it turns out that there is some life activity even in the desert, and thus covering it with semiconductors is not necessarily environmentally friendly) and what to do with the resulting uncontrolled energy flow.

Installing solar panels on the roof of a home, selling the excess energy to the grid, becoming profitable (ideally) within a decade, and concluding that the greening problem has been largely solved is a third oft-repeated mantra.
The fallacy here should be self-evident: household electricity accounts only for a negligible part of an individual's energy footprint. Industry, construction, transportation and heating (including those solar panels on the roof, of course) all come at the expense of some other source of energy.

So renewable energy has two fundamental disadvantages; namely, dispersion and unmanageability. The only energy source that is (almost) free of these flaws is hydropower, which relies on nature to concentrate and stabilize energy. Hydropower is also the only means of large-scale electricity storage.

However, since hydropower is a concentrated form of renewable energy, its overall resource remains limited (and there is very little of it in Estonia). In any case, not even the nations with the most hydropower resources such as Iceland and Norway have been able to achieve a total green transition.

Regarding the unmanageability of renewable energy: on the face of it, it seems that energy just needs to be buffered for a couple of days until the sun comes out again and/or the wind starts blowing (hence Elon Musk's reference to a few square kilometres of battery bank.)

It has also been proposed that renewable generation will self-stabilize in a larger (and high-capacity) electricity grid given that the sun is always shining or the wind is always blowing somewhere. With more consideration, however, it becomes apparent that there is no sensible or definite limit to weather variability (as a statistical phenomenon).

The key period of long-term variability is the seasonal period, or a year. Organic ("old-fashioned") solar energy is mainly based on this: in summer photosynthesis stores solar energy in biochemical forms (crops, wood, hay, etc.), which is then consumed as needed to survive the winter.

Modern renewables differ in that they take primary energy (sunlight/heat or air/water movement) and quickly convert it to electricity, often with high losses.
Even if this slightly increases the amount of raw energy extracted from nature, it exacerbates the problem of unpredictability. After a prolonged period of drought, even hydroelectric power plants may be unable to generate energy.

If the studies are accurate, the energy produced by a solar panel or wind turbine can be several tens of times greater than the energy necessary to construct, maintain, and dispose of these devices during their entire life cycle. (However, the cost of materials per unit of energy produced exceeds by orders of magnitude the corresponding figures for fossil and nuclear energy, the other study finds, and the situation is just as dire for waste.)

Nevertheless, the initial assumption is not bad. Long-term energy storage appears to be responsible for this metric's catastrophic decline. Let's take a basic scenario. Estonia generates roughly 1000 gigawatt hours (GWh) of uncontrolled renewable electricity annually (wind + solar). Assume that we want to store 500 GWh of this energy for long-term supply security (surviving the winter months, etc.) The only pumped hydro plant now under construction will have a storage capacity of 6 GWh. So, we would need about 80 of them! Even the first one will not be operational until 2029, and that is after nearly 20 years of development and construction.

The same issue may arise if another "modern" energy source is used instead of hydropower. In the case of hydrogen energy, for example, wind turbines and solar panels require high-tech equipment such as an electrolysis unit, a fuel cell, and a hydrogen-handling infrastructure, etc.

While the aforementioned hydro pump makes sense in terms of smoothing daily energy fluctuations and is expected to have an efficiency of greater than 80 percent, the energy loss in the cycle electricity -> hydrogen -> electricity is two to three times greater.

So even if hydrogen technology were safe and cost nothing (neither of which is true), there would be a great deal less renewable energy remaining. In the distant future (when fossil energy is history), the synthesis of a chemical energy carrier (ideally liquid fuel) will be necessary, not so much as a buffer for renewable energy, but because long-distance transportation (ships, planes, and trucks) is unlikely to be powered by electricity.

In practice, this implies that the bulk of fossil-fueled power plants cannot be shut down and must remain "on standby" to cover any short- or long-term energy deficit.

Utilizing extremely fluctuating electricity costs to bring consumption in line with production also helps to alleviate the problem. No wonder biomass is the leading renewable energy source in Estonia. Although biomass allows for the controlled energy production, its energy density (capacity per unit area) is even lower than that of wind and sun.

The average energy densities are 15 watt per square meter (W/m²) for solar, 3 for wind, and 0.5 W/m² for biomass. Other forms of renewable energy (hydropower, geothermal, and tidal) are far less efficient. In other words, renewable energy sources that are both reliable and manageable are scarce.

The dispersed and unmanageable nature of renewable energy and the technological complexity of "modern" renewables pose many challenges that cannot be addressed here: huge negative impact on the environment, lots of hazardous waste (in many ways more hazardous than radioactive waste), lots of new "green" jobs (curiously thought about as something positive), etc.

Sustainability of industrial civilization

To be able to see the bigger picture, it is important to recall that the driving force behind industrial civilization is the introduction of ever-more-advanced, in some ways superior (not to mention nonrenewable) energy sources that enable technological progress and, consequently, an improvement in the quality of life. "Superior" can refer here to increased energy capacity or usability. With renewables in mind, even the steam engine was cumbersome and inefficient (i.e. biomass).

How can this paradigm, however, manage resource depletion and environmental contamination? The only possible (but not guaranteed) solution to these problems is to continue progress, i.e., to transition to the next energy source before both problems become serious. As was the case for almost thirty years with nuclear energy, stagnation is bad.

The next-generation energy source will have higher energy density or volume, so increased energy consumption will not necessarily have a greater environmental impact. For instance, the extensive use of fossil fuels has made it possible to reduce deforestation in some countries (including Estonia). By analogy, a number of synthetic materials (produced from petrochemical residues) could be thought of as more environmentally benign than their 'natural' counterparts. The higher price of the latter usually comes along with its larger energy footprint.

In any case, the use of nonrenewable energy sources has undesirable or harmful side effects, such as pollution, climate change, and waste. The next generations of technology (and people) will be responsible for mitigating them. It is important to recognize that these negative side effects are generally marginal compared to the increase in living standards brought about by improved energy supplies.

The air, water and food we consume now are often cleaner (and better regulated) than they were before the industrial revolution (nearly 300 years ago). Not to mention the fact that hunger is almost non-existent.

Yes, according to various estimates, several million people die each year as a result of air pollution from fossil fuels. This is primarily due to the fact that these people die a few years earlier than they would in a perfect world without air pollution. Without the widespread usage of fossil fuels, famine and disease would have inhibited progress, and these people would never have been born.

Even the simplest (often more than a century old) scientific models representing the thermal balance of the Earth and its surrounding atmosphere under solar radiation are broadly consistent with the observed rate of global warming. Each successive molecule of CO2 emitted warms the atmosphere less than the one before it. This is because the CO2 distinct absorption bands (in the infrared) responsible for the greenhouse effect are already saturated.

Nor is there any reason to believe that the equilibrium in question (as it evolved long before widespread human activity) is in any way delicate or unstable, the slightest disturbance of which could trigger a catastrophic chain of events. The contribution of atmospheric physics (including the greenhouse effect) is somewhat secondary - the base temperature is still determined by the intensity of solar radiation (solar constant) and and the albedo of the Earth (reflection coefficient).

Physically speaking, the only disadvantage of the greenhouse effect is that more heat energy is "trapped" in the atmosphere, which can lead to more severe weather conditions. In any case, despite climate change, climate-related mortality has been on a long-term downward trend despite the rise in world population. This means that even while the climate on average has become more dangerous, technology is offering increasingly better protection against it.

In the end, however, there is a cost associated with climate change (both for humans and other species) and that is the cost of adaptation. On the other hand, these changes are slow, and everything eventually breaks down, thus civilization must keep reconstructing itself all the time.

The usual perception of natural resources is also problematic. Strictly speaking, there are no natural resources; there are only raw materials in diverse forms. Raw materials become resources for us when they are used, i.e. acquire value. Therefore, the quantity of natural resources is generally not precisely to define. For example, despite the ever-increasing consumption of fossil energy, it will continue for the next 50 years or so, just as it did half a century (or even a century) ago.

Fears about the imminent threat of overpopulation alongside with "resource shortage" have also been often debunked. Fossil energy is expensive today but this is rather due to a number of political factors, such as CO² restrictions, the disruption of global supply networks and the abandonment of unconventional oil and gas production.

Fossil energy lasts on the order of 1000 years and will eventually end, sooner or later, either due to resource depletion or high CO² emissions (climate becomes unbearable or there is nothing left to breathe).

There will be many different generations of nuclear and fusion energy. They offer a way out of the problem of atmospheric pollution, but each is likely to have some minor but unavoidable side-effect, such as radioactive waste or thermal pollution. These energy resources are not quite infinite, but hopefully they will last at least 10⁵-10⁶ years.

It is difficult to predict what will happen next, but solar would be the natural next step. The sun is a stable, maintenance-free thermonuclear reactor that lasts 10⁹ years. Of course, calculating on such a scale deals with solar no longer as "renewable energy" but essentially means bringing humanity to the so-called Type II civilization level (on the Kardashev scale, science fiction - ed.)

In any case, according to this "progressive" viewpoint, the sustainability of renewables is guaranteed for at least the duration of the sun. But in the case of renewable energy, we can only be sure that it will guarantee endless vegetation at pre-Industrial Revolution levels, and that's assuming a significant decrease in human population.

Nuclear energy?

On the face of it, a large-scale switch to CO²-free nuclear power would have been the solution to energy shortages, air pollution and global warming.

Indeed:

• Within a few decades, nuclear energy supplied around 20 percent of the world's electricity after a successful start more than 60 years ago.
• Measured by the number of deaths per unit of energy produced, nuclear is likely the safest method of energy production (ahead of wind and, according to some data, solar). Moreover, considering that the number of wind turbines in the world is approaching one million and the number of households with solar panels is probably tens of times greater, the dangers of wind and solar energy are not at all surprising. Also, the issue of "affordability" remains: one unit of unmanageable renewable energy cannot be compared to the same quantity of steady nuclear or fossil energy. 
• Nuclear waste is by far the "best" waste: its generation is low (because of the high energy density of nuclear fuel), it is highly localized (stored near to the nuclear power plant), and its health hazards (radioactivity) are intrinsically temporary and easily detectable. (A simple Geiger counter, an electronic instrument used for detecting and measuring ionizing radiation, is now almost the size of a mobile phone and costs around €100.)
• What is all the more striking is that, while new technologies are usually expensive at the beginning and then become cheaper after widespread adoption, the opposite has happened with nuclear. Under the auspices of "greater safety," nuclear energy has been made costly and noncompetitive.

On the one hand, this is certainly due to irrational fears and scientific misconceptions that have developed for one reason or another. The opposition to nuclear power arose long before the Chornobyl incident. For example, an earlier film demonizing nuclear power, "The China Syndrome," was released back in 1979. On the other hand, however, it also seems to be due to certain value-based, almost religious attitudes in society.

It is not morally acceptable for many that humanity operates with such exotic/dangerous forces of nature ("atom splitting"), has access to nearly limitless  energy and is "expanding" on Earth. In wealthier countries, it has been possible to maintain such attitude quite until recently, as fossil fuels were abundant, the climate was not too bad and the promise of renewable energy loomed in the horizon. In addition, it was possible to simulate a "green turn" with various "greenwashing" strategies.

Natural gas is the only idea that makes sense at first glance, as fast-reacting gas plants are best suited to balancing variable wind and solar electricity, and natural gas is the fossil fuel with the lowest CO² emissions. However, even in such a system there are so many hidden fossil energy costs that it is not at all clear if renewable energy makes any real contribution or whether it is a parasitic sector. Perhaps the same environmental impact could have been achieved just by developing fossil energy without building a single wind turbine or solar farm.

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