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Tämä on yksi niistä postauksista mitä en olisi uskonut tarpeelliseksi, mutta aina oppii uutta. Kummallisen moni näyttää elävän siinä käsityksessä, että maanviljelyksen “jätevirrat” voivat olla merkittävä energianlähde. Olen kirjoittanut tästä ennenkin, mutta palataan nyt tähän. Kertaus on opintojen äiti.

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Kestävä bioenergian potentiaali

Suomessa mm. Neocarbon projekti ja Vihreät väittävät peltobiomassassa piilevän yli 20 TWh:n aarteen. Lähteenä tälle on Vihreillä Hannu Mikkolan väitöskirja.  Jos oikein sitä luen, mitään ympäristövaikutusten arviointia ei oikeastaan ole siinä tehty tai verrattu esimerkiksi vaihtoehtoisia toimintatapoja toisiinsa. Siellä ei siis ole pohdittu olisiko esimerkiksi metsittäminen parempi vaihtoehto tai sitä voidaanko näitä energiaplantaaseja tarvita tulevaisuudessa ruuantuotantoon.  On laskettu hehtaareja ja hehtaarikohtaisia tuottoja mm. ruokohelppiplantaaseilta ja päädytty tulokseen, että oljessa olisi energiaa ehkä 8 TWh ja että ruokohelvestä voisi saada ehkä 12 TWh. Noita voi verrata esimerkiksi Suomen energian kulutukseen, joka on lähempänä 400 TWh:a, mutta onko todellinen potentiaali likimainkaan edes tuon suuruinen? Rohkenen epäillä, että ei ole.

ECOFYS arvioi sivuvirtojen kuten oljen kestävää potentiaalia EU:ssa. He siis arvioivat myös sitä, että osalle näistä sivuvirroista on muutakin käyttöä ja kaikkea niistä ei voi ekologisin perustein hyödyntää (oljesta osa on jätettävä maaperään). He eivät antaneet arvioita Suomelle, mutta Tanskaa kyllä käsiteltiin. Oljen kestäväksi potentiaaliksi arvioitiin noin 3.2 miljoonaa tonnia “märkää massaa” (wet matter). Tästä määrästä osaa tarvitaan esim. karjan kasvatuksessa, mutta 1.4 miljoonaa tonnia arvioitiin potentiaaliksi energiantuotannossa. Jos energiatiheys on noin 9MJ/kg, tuo tarkoittaa noin 3.5 TWh energiaa. Tuo määrä on Tanskassa käytössä jo nyt eli lisäyspotentiaalia ei ole muuten kuin kestävyysnäkökulmat sivuuttaen (mitä 100%RE visionäärit valitettavasti tekevät).

Miten tuo arvio Tanskalle suhtautuu meihin? Arvio Tanskalle oli siis, että oljista 3.5TWh, kun taas Mikkolan väitöskirjassa oli Suomelle 8TWh. Tanska tuottaa viljoja vuodessa reilut 9 miljoonaa tonnia, kun taas me noin 3.6 miljoonaa tonnia. Kaiken järjen mukaan meidän kestävä potentiaalimme oljelle on alhaisempi kuin Tanskan, koska olkea syntynee vähemmän? Mikkolan väitöskirjan luku lienee vain arvio kaiken pelloilla kasvavan biomassan (jyvät poislukien) energiasisällöstä. Realistinen potentiaali liikkunee TWh suuruusluokassa. Onko sen käytössä mitään järkeä kun kustannukset ja vaadittava työ otetaan huomioon onkin sitten toinen kysymys. Pääpointti on kuitenkin se, että näistä jätepuroista puhuminen on korvikepuuhaa todellista dekarbonisaatiota odotellessa.

 

Renewables industry lobby group REN21 has published a new report “Renewables Global Futures Report 2017“. The report is written by Sven Teske who used to write similar reports together with the industry lobby groups for Greenpeace (some content has been copied from there). For this new report Teske et al. interviewed a bunch of “renowned energy experts” who were selected by asking for suggestions from…REN21! As a result of this careful selection process, they created a nice safe space of experts whose interests and preferences likely align well with the objectives of REN21. Success guaranteed!

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Weird…

Strangely they then explain how they ranked each candidate according to their level of faith, but as far as I can see, nowhere do they either explain what their ranking was or how it was used. There is some discussion that seems to indicate that faith was strong mainly among europeans and among these germans and greens seemed to be strangely well represented. Go figure.

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Increased demand. Those thinking demand will be lower in 2050 are outliers.

Now it is not too surprising that those interviewed have a relatively high level of faith in renewables, but it is more interesting to explore how their expectations actually align with serious climate policies. This report ignores actual emissions implication almost entirely and one can only wonder why? It is not, however, difficult to see the implications. First of all, even most of their carefully chosen experts foresee substantially increased energy demand.

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“Expert debates within the climate and energy communities take place largely within their own silos…”

Bizarrely the report then seems to criticize its own experts by speculating on why they are wrong. So who were the renowned expert? Teske or the people interviewed?

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More renewables, but lots of other stuff as well and how much of this is things like biofuels?

As for the share of renewables of the overall demand there were varying opinions, but it seems that median expected share in 2050 was around 50%. So lets put things together. Around 40% demand increase, maybe 50-60% RES share and we are left with maybe 30% emissions reductions from energy production by 2050. So sad. So their carefully selected experts do not, in fact, believe that renewables can deliver the kind of emissions reductions we need. Why didn’t Teske or REN21 highlight this? It does not promote happy talk for sure, but maybe time for happy talk is over and we should start feeling inspired by policies that would actually be meaningful. Grownups see the need for action on a broad front with all possible tools on the table.

PS. The report has also weirdly misleading spin. See below for an example. For those familiar with Teske’s past behavior this is not too surprising. When IPCC made the mistake of giving him the microphone when their SREN report (on renewables only energy issues) was released. He promptly used this as an opportunity to promote Greenpeace’s and industry’s E[R] scenario as representative of the SREN scenarios while ignoring contributions from most other authors. In reality  E[R] was an extreme outlier even in the context where most authors were probably more kindly disposed towards renewables than the average.

Correction added 8.4: I misintepreted the below figure. (I thank Ikemeister for pointing this out.) The text talked about doubling (from 28%) so the claim is correct (although phrasing/spin could be clearer IMHO). I cannot resist pointing out how the text accompanying figure on RES share of final demand was crafted. Note that more than 60% share was guessed by about 49%. Text quotes higher figures by using subsamples from India and Europe. Desire to spin the right narrative was stronger than desire to use all the data.

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No they didn’t. About 41% did. (note correction)

Added 8.4.2017: Note also how skewed the distribution of experts is. About half seem to be from  few west european countries (most are germans), from Japan, or US. That is less than 10% of global population and from rich countries that are unlikely to determine the energy trends for humanity in the next decades.

Addition 13.4.2017: I will add a little news on the issue of “spin” since this happened almost at the same time as this post. Reuters relying on some Greenpeace report announced that China will spent a lot on solar and wind etc. Being a sort of guy who likes to go to actual sources, I tried to find it. I found a press release announcing this, but then had to follow a link to a Greenpeace-China page . Then from the very bottom of this chinese page I eventually found a link to the actual report (in chinese). I almost got a feeling they didn’t want people to actually read it. So of course I had to have a look and ran it through a translator. Below is the reports vision on chinese electricity supply and demand until 2030. The vision implies substantial increases in the use of fossil fuels. Increases in low carbon sources is inadequate to even cover the rising demand let alone decarbonize. One would think this would be relevant piece of information for public to know, but clearly Greenpeace thought otherwise.

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Vision implying climate failure. 

 

In the earlier post I summarized my estimates on the limits to capacity utilization if production is done either with wind or solar power.  Here I will (over)think implication a bit further.  mthOn their own wind and solar power implied strong restrictions on achievable utilization rates. Overbuilding generation capacity (and associated distribution system) could increase utilization rates, but at the expense of ever increasing amount of wasted power and underutilized power lines. Storage could also help, but smoothing out the production profile would require large amount of underutilized storage capacity. There doesn’t seem to be away around this. Low capacity factor of variable power source has cascading effects elsewhere. If not fixed capacity utilization of end users would be strongly constrained and most likely too low to enable profitable business. On the other hand attempts to fix the problem would imply underutilized generators, power lines, and/or storage. Technical developments will not change this since the problem is not due to specific technology or costs.  Are there ways around these problems? Of course…

If you are planning to invest in a new plant producing for example solar panels and you find production to be unprofitable with utilizations rates implied by solar power, your first choice is simply not to invest. If economic preconditions do not exist, production never materializes even if we might find such production desirable or even critically important. Production would either not happen or move to a place where higher utilization rates are possible. Various shades of gray might also exists as they do today especially in the developing world. If production process is such that you could for example store some parts for later use, it might be possible to outsource only those phases which require reliable power elsewhere. Of course, this still opens up possibilities for those not saddled with the same constraints.

Another option is not to rely solely on variable renewables, but to have a fleet of dispatchable generators delivering the power services variable renewables cannot deliver. Today this most likely implies burning fossil fuels, but in principle hydro and nuclear power would work as well. This again implies overbuilding infrastructure and is unlikely to be economically optimal. However this fundamental reliance on existing infrastructure is the order of the day in the developed world.

Visions where variable renewables dominate are aspirational marketing material while on the ground unholy alliance seems to have quietly developed between many renewable and fossil fuel lobbyists. Cozy reliance on fossil fuels enables somewhat more variable renewables to be built before technical limitations become apparent. Supporting this modest buildup (with public money) buys fossil fuel industry social licence as well as removes long term threat of actual decarbonization. Petty about the climate, but the constituency for whom this is actually a priority is weak.  This is welcome also for many politicians who are only too happy to project an appearance of activity (at relatively low cost) while their policies imply changes which have a marginal impact on the actual problem. This relates to deep decarbonization in a same way as “champagne socialism” relates to revolution of the proletariat.

I recently read a very interesting book “Fossil Capital” by Andreas Malm on the history of industrial revolution in the United Kingdom. (Note: book is only worth reading until chapter 12. There the author got tired of thinking.)  Malm focused on the question of why coal and steam engine won over water power in the early decades of the 19th century. Remarkably coal did not win because water resource would have been insufficient. There was still plenty of untapped potential in the UK. Also coal did not win because it was cheaper. In fact, mechanical power from steam engines was more costly and many were of the opinion that it was also of worse quality. So what happened?

There were many overlapping reasons. For example, factories followed labour to the cities. In the early 19th century it was already clear from the demographics that labour was to be found in the cities. Water power was dispersed and getting meek labour to run the machines in the middle of nowhere was harder. In fact, owners of water powered factories were relatively more dependent on the apprenticeship system providing them with, what can apparently with some justification be called,  slave (child) labour. Water power was also more variable than steam, which made it even more important to have well behaved labour that would be willing to work long and irregular hours.

However, it turned out labour did not think their position was optimal (go figure) and started to make noise. This resulted in legal (and actually enforced) restrictions on working hours and gradual improvement on workers position. (It also induced technological change that made large number of especially troublesome workers redundant, but let us not talk about that here.) Owners did not of course like these limitations and lobbied against them, but relatively speaking those using steam found it easier to adapt. They could live with the shorter and more regular working week since reliable power could enable high productivity during working hours. Coal became the backbone of british industrial might and the road was opened for more broadly shared economic growth.

So can we learn something from this? I think we can since economic and social arguments for why coal won have not disappeared. If you listen to todays renewables promotion, you will be constantly bombarded with statements about how huge the potential energy resource is and how cheap it is…or is going to be any day now. Might it be a cause for concern that these two reasons were also promoted by water proponents in the 19th century Britain just when coal was taking over? Might there be a risk, we are discussing beside the point? If excessive reliance on variable renewables end up limiting capacity utilization, is there not a similar risk that water power faced in the 19th century? Who bears the cost of lower utilization? Labour? Lower salaries and/or more irregular working hours anyone? Vacations in the winter since solar power produces mainly in the summer?  If push comes to shove and such questions have to be asked, I am quite sure any techno-fetishes we might have, will evaporate.

To me conclusion seems clear. It is unlikely humanity will ever be primarily powered by variable renewables. If fuel etc. costs for dispatchable generators are high compared to the cost of electricity from variable renewables, wind and solar might be economically justified as a part of a more diverse fleet of generators. However, it is also possible that on economic grounds they will remain niche producers whose existence is dependent on subsidies and political good will. Future will tell.

This will probably be a fairly long post mainly summarizing findings from my simple toy model….so proceed at your own peril.  For a while I have been interested in how the properties of the power source affect the end user. For the consumer different power sources deliver very different value, but the public discussion is typically centered (more or less honestly) on costs. I think one issue of great relevance is the capacity utilization and the aim of this post is to record my studies on the matter. In particular I wish to explore the variable power sources such as wind and solar in the context of capacity utilization. My thoughts are in the end closely related to “capacity factor rule” discussed by John Morgan, but I approach the issue from somewhat different angle.

What is a capacity utilization  and why it matters?

Capacity utilization compares realized production with what could be possible. The concept seems to be somewhat fuzzy since theoretically maximum output could be defined in different ways. However, for an advanced economy capacity utilization is high, for example, in EU it is typically higher than 80% with a scary dip during last financial crisis. In an undeveloped country capacity utilization is lower, for example around 55% in Bangladesh. This makes sense, since things like poor infrastructure hamper production that might have otherwise happened. High capacity utilization is needed especially when lots of capital is spent since otherwise production could not cover capital costs. If high capacity utilization cannot be ensured, investments requiring large amounts of capital will not happen (unless one finds someone to pay for the losses).

In a developed economy capacity utlization is not really limited by the power supply. We get power from the plug whenever we need it. Capacity utilization is limited more by things like rising labour costs if one aims for maximum production or perhaps uncertainty on whether or not a buyer can be found for the product. However, our electricity production follows the demand and not all power sources can do that. Some view it desirable that consumers should in fact adjust their consumption according to weather. This raises the question: “How will this limit the capacity utlizations?”

This is a hard question and I can only scratch the surface here. I assume a “machine” or factory that can use certain amount of power and what is produces is proportional to its electricity consumption. I will then either use wind power or solar power as a power source and also add a storage to help even out the power variations. If there is excess power and storage is not full, we fill it. If power supply is lacking, we drain the storage. (I assume 80% round trip efficiency.) How much power machine can use, is a variable. It probably makes no sense for this to be higher than the wind or solar capacity, but if it is reduced utilization rate for the machine can probably be increased. It should be noted that the estimates below do not (of course) use the economists definitions for capacity utilization. This is more likely to give an estimate on the additional limitations on capacity utilization on top of all those other factors that are operating in any case.

So let me quickly summarize what I find…

Figure 2: Wind power source limited capacity utilization as a function of “machine capacity” (i.e. what fraction of power source capacity it can use) and storage (days at average wind production). Wind power data from UK 2013.

Figure 3: same as Figure 1, but using solar power as a source. (Production data from Germany 2015.)

Figures 2 and 3 show my rough estimates for the “capacity utilization” as a function of machine capacity and amount of storage (hours of average power production). If machine capacity is equal to the capacity of the power source, capacity utlization is limited by the capacity factor of the power source. As machine capacity is reduced and/or storage is added capacity utilization can increase. However it is very hard to get to a situation where power source would not be a factor substantially limiting the overall capacity utilization.

In terms of capacity utilization wind power tends to beat solar power which has strong seasonal production profile. Removing that is hard since it would require massive amounts of seasonal storage which would (by definition) be used only by about once a year.

As machine capacity is reduced, the “factory”can run at a higher capacity utilization, but then certain fraction of the produced power will be wasted although waste can be reduced somewhat by storage. If we aim for high capacity utilization, wasted fraction can unfortunately be substantial. The unit cost of useful energy will rise with increasing waste.

Figure 4: Fraction of wasted wind output.

Figure 5: Fraction of wasted solar output. (Once daily variation is covered it is very hard to change things by adding even more storage.)

Waste can be reduced with storage, but then the question arises that how efficiently this storage is being utilized? Figures 6 and 7 illustrates this. If we add so much storage that capacity utilization is high and amount of wasted power is low, we tend to have a large amount of under utilized storage capacity lying around. Storage that is combined with solar power tends to be more efficiently used because of regular daily variation.

Figure 6: How efficiently storage is being utilized with wind power. (Here the scale is more arbitrary. I assumed full utilization amounts to one full cycle a day.)

Figure 7: Same as figure 5, but with solar power.

I suspect that these estimates are in fact too optimistic. If I choose a point from figure 2 with relatively high “capacity utilization”, the power supply for the machine is still quite erratic as seen in Figure 8.

Figure 8: Example power input to the machines when machines powered by wind had a capacity of 0.26 of wind capacity and system had 36 hours of storage at average wind output. Still a mess.

Maybe there are processes that do not mind this, but there are  also plenty of industrial processes where steady power supply is needed and where abrupt power cuts will undermine the economics of the plant. (It would be interesting to have real world examples of production economics as one changes between power sources. Do you know any? I suspect that current way of delivering power to industries in developed economies is close to optimal for their needs.)

I think I will stop here and discuss later what I think this will imply. Main point here is that nature of the power source will affect the capacity utilization and have economic consequences that are not accounted for when myopically computing the “cost” of electricity for the power sources.

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