The sunflower
It bows down to the Sun
The image of resilience.
Showing posts with label solar energy. Show all posts
Showing posts with label solar energy. Show all posts

Monday, August 28, 2023

Energy too Cheap to Meter. A Comment by Christian Breyer on the Future of Renewables

 


A picture I took a few days ago of the sun setting behind the chimney of a house in central Tuscany. The sun is the ultimate source of energy for us, and it comes for free! Too cheap to meter.


Last year, I published a post on "The Sunflower Paradigm" blog where I discussed the sun as a "nuclear plant in space," the embodiment of the old concept of "energy too cheap to meter" that was expressed during the euphoria of the nuclear age, in the 1950s.

The low cost of the current generation of solar and wind energy makes it possible to return to that old concept. We don't need to bother with complex, expensive, and dangerous nuclear reactors on the Earth surface. We can use a nuclear fusion plant located in space; the sun. It works, it is already there, it costs nothing, and we now have good technologies to convert the energy it creates into electricity. It is cheap energy. Not yet "too cheap to meter" but moving in that direction. Look at these impressive data:



Unfortunately, many people (including opinion leaders and decision-makers) seem to have entered a negative psychological loop that pushes them to deny the usefulness of renewable energy and wait instead for impossible miracles, well knowing that they will not arrive. It is discussed, among others, by Glenn Albrecht in his book "Earth Emotions, " where he says

" When life becomes intolerable and there seems to be no way out, prayers and desperate hope for a final end, so that we might start all over, beckon. The nonbelievers in "rapture" religion simply engage in disaster euphoria, take drugs, and drink more."

So, I thought that the readers of this blog may be interested in the comment on the concept that I proposed that I received from Christian Breyer about this Christian is Professor for Solar Economy at LUT University, Finland. one of the foremost researchers in the field. is his comment, published with his kind permission and with a few minor edits to improve clarity. 

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Christian Breyer wrote:


Ugo, first of all, many thanks for your initiative.

Personally, I do not like much the wording ‘fusion power’ since it has a legacy of decades-old promises without any relevance for reality due to ongoing failures – why solar energy should be downgraded by such a bad reputation? That may be only my personal thoughts, since ‘fusion power’ (on earth) is nice wishful thinking, and, in the end, great research for high-temperature physics at its edges and respective material science, but has no relevance for energy supply. In case it might be successful, then it would be available at a time when the (solar & wind) powered global energy system has helped to survive the climate emergency. In any case, with all cost estimates as of today for a non-existing technology, it seems to be not competitive at all, since a 100% renewable energy system based largely on solar and wind will cost the same or less, but with a technology that can be handled by all countries globally, in particularly in the Global South, where most the additional energy demand will arise.

As a physicist, I fully agree that you are right 😉 and the fusion power of our sun is the way forward (among some other solutions). There may be another less helpful misunderstanding: solar power plants in space for sending energy on earth (space solar power). This option is nicely discussed from time to time, but chances are high that it will be never introduced at large, finally due to costs (higher than on earth) and the risk (destroyed due to all the garbage in the orbit and attacks due to warfare – we learn right now that nuclear threat in warfare is no theory but brutal reality).

We are now in year 47 of 100% renewable energy systems research. The following is really important:

Base load demand: will exist as long as a civilization is using electricity

Base generation demand: is something of the past of a fossil-nuclear energy system which is NOT required in an energy system based on solar and wind energy and modern technology options utilizing flexibility which is available in large quantities, and, NOT compromising energy services at all (for instance shown here: https://www.sciencedirect.com/science/article/pii/S0360544221007167; in more conceptual detail here: https://www.sciencedirect.com/science/article/pii/S0306261920316639, or here: https://www.sciencedirect.com/science/article/pii/S036054421831288X).

Modern energy system analyses are done in hourly resolution with real weather data and real demand data, so that it can be easily checked how a system has to be designed in such a way that it works properly at all hours of the year.

For those who still think that base generation would be impossible (or required) – we have even prepared a scientific paper in which this is shown on the based on solar and wind power (https://doi.org/10.1016/j.jclepro.2019.118466). The PhD student couldn't understand why such a ‘nonsense’ as base generation should be even published, since in state-of-the-art scientific publications, it has been shown in hundreds of papers that it is not required. However, for the debates on the topic, it helps to show that it will not be required, but even that could be done (BTW, for substantially less cost than new nuclear power …).

This is also discussed and embedded in a topical review on 100% renewable energy systems research as recently published (a bit more below): https://ieeexplore.ieee.org/document/9837910

RethinkX: Be aware that the oversimplified approach of Seba et al. is dangerous and makes only sense for those who have little clue about a real energy system. Why? An energy system based on solar-wind-batteries (and nothing more) is NOT stable and will NOT work for an uninterrupted electricity supply. I strongly suggest getting the RethinkX ideas published in a scientific journal, so that all the limitations of the oversimplification are made transparent.

The literature review on EROI in the linked Earth4All document is very good and worth reading. The fundamental impact of the learning rates is well presented, BUT a real energy system is MUCH more complex than the oversimplification indicates.

A more realistic approach is close, as around 90% of all electricity could be from solar and wind power, and about 95% of all storage could come from batteries, as shown in this paper (https://www.nature.com/articles/s41467-019-08855-1), BUT, the lacking discussion on the difference to 100% is the reason why skeptics may believe that a solar and wind-powered system would not work (… “in hours of lack of sun and wind” …). A variety of smaller solutions enable the low-cost and stable 100% renewable solution. The much-discussed sector coupling (also called smart energy system) comes on top and further reduces the energy system cost. Again, more food for thought and references in the above-linked topical review article.

Outlook:

I do not want to be pessimistic, there is much indication to welcome a bright future.

In a recent review article, researchers from 15 universities (several are here on this list) have summarized the state-of-the-art of 100% renewable energy systems research:

https://ieeexplore.ieee.org/document/9837910

(overview on the roots of the discipline, development of publications, relevant global studies, regular criticism and the response [EROI, materials, variability, costs, a.o.] and a research outlook) – 400+ references are provided for further reading, and the knowledge of several key researchers in the field is aggregated, also representing the 5 teams with the most published articles in the field – while the emphasis was high to be as inclusive and balanced as possible when it comes to technologies, approaches, discourses and specific topics of relevance.

We have all in our hands to create a truly sustainable civilization, as for the first time humans have the technology and means to enable a world of energy wealth for all humans by the end of this century. This even implies the reduction of CO2 in the atmosphere, as it would be energetically affordable, and sustainably doable (although not with BECCS). There seems to be no fundamental show-stopper as long as (sustainable) renewable resources are used and a circular economy is the basis of our activities.

Best regards,

Christian











Friday, March 3, 2023

Electricity: the universal energy currency

 

By Harald Desing

Energy is conserved. Counter to common language, energy can neither be "produced" nor "consumed", but only transformed. However, there are more and less useful forms of energy: electricity, for example, is extremely versatile and can be transformed into any other form of energy with close to 100% efficiency. In contrast, low temperature heat cannot do much work anymore; it is the energy "waste" with no work potential. The work potential is called exergy: electricity has 100% exergy content, whereas heat at the same temperature than the surroundings has 0%. Society is driven by useful work provided through different energy resources. So, different energy forms should be compared with the useful work they are able to do.

Commonly, this is not the case. Energy statistics, such as the IEA or from national statistic offices, do compare apples with oranges: "Primary" energy is accounted on different levels: calorific energy content of fuels (that is the heat potential that can be generated by burning the fuel) alongside with solar electricity and geothermal heat at different temperature levels. All of them have different work potentials, and they are later used as different forms of energy: heat for buildings and industry, electricity, or motion for mobility.

When we defossilize the energy system, most of the fossil energy applications, which are not yet electricity, have to be replaced by renewable electricity. For example, instead of internal combustion engines in cars and trucks, we need battery electric vehicles and electric trains; gas boilers can be replaced by heat pumps powered by electricity; and high temperature heat for industry with either direct electric heating (such as an electric arc furnace) or hydrogen produced with renewable electricity (such for hydrogen-reduced steel). Low temperature heat could also be provided by solar thermal collectors, with a similar efficiency than converting to solar electricity first and to heat with heat pumps later. High temperature heat could be provided by concentrated solar systems, however, this is currently not very practical for most applications in industry. In particular cases, it may make sense to provide heat directly from solar, biomass or geothermal. However generally, electricity is the universal and versatile intermediary form of energy for all sectors.

We do not have to replace "primary" fossil energy, but only the useful work they provide to society. Fictively converting all primary energy to electric energy equivalents using state-of-the-art conversion technologies, provides a more reasonable estimate for what really needs to be replaced. It reduces the energy supply to society from almost 19 terawatt (TW) in 2019—as counted by IEA as "primary" energy—to 7.3TW.  Renewable energies already provide 15% of this, so "only" 6.3TW needs to be replaced during the energy transition with renewable electricity.

Sometimes, this reduction is labeled "gigantic efficiency improvements" when switching to RE systems, but actually it is merely counting energies on the basis of usefulness to society. The efficiency of the subsequent energy services remain the same. The efficiency of the energy provisioning system, in contrast, could be measured by tracing energy conversions all the way back to their origin. For most energy forms, this is our sun. Hydropower is nothing but converted sunlight: sunshine on oceans evaporates water, forms clouds and generates winds that carry vapor over land where it falls as rain. The height difference of the runoff back to the oceans is what can be used as hydropower. This description makes it clear already that from the original solar energy, only a tiny fraction can be converted to hydroelectricity. The same applies to wind and biomass. All of them are much less efficient than direct solar energy conversion. Fossil fuels are also nothing but (ancient) sunlight. They had been slowly built over many million years by buried biomass; now we burn them at a rate more than ten thousand times faster than they were built. The solar energy that created coal, oil and gas deposits is again much more than solar energy stored in recent biomass, reducing the conversion efficiency from sunlight to useful work even further. Nuclear, geothermal and tidal energies do not originate from our sun. They originate from exploding stars and need to be traced back all the way to the big bang. The energy from our sun can be traced back to the big bang too, which would be truly primary energy: all the useful work at our disposal originates from there.

Due to all the additional conversion steps for other energy forms, direct solar energy conversion is the most efficient way to provide useful work to society. And electric energy is the embodiment of useful work (100% exergy), which is why it is ideal for comparisons and modelling substitutions among different energy provisioning systems.