Siirryn wordpressin puolelle/Moving to wordpress

Koska wordpressin ympäristö vaikuttaa toimivammalta, päätin siirtää blogini sinne. Tämä blogi pysyy kyllä pystyssä, mutta uusi sisältö ilmestyy jatkossa osoiteeseen passiiviidentiteetti.wordpress.com. Olen myös siirtänyt täällä olevan sisällön uuteen blogiin ja siirto tuntui onnistuvan joitain videotiedostoja lukuunottamatta hyvin.

This blog will move to passiiviidentiteetti.wordpress.com.The old content will remain available here, but can also be found in the new site.

Presidentinvaalit 2012

Olen tyytyväinen, että toisella kierroksella ovat vastakkain nämä ehdokkaat. Jos haluat edesauttaa kiinnostavampaa toista kierrosta, niin käväisepä tekemässä lahjoitus Haaviston kampanjaan. Tässä vaiheessa tehdään tärkeitä päätöksiä siitä mihin kampanjoissa on varaa ja Haaviston leiri on varmasti köyhempi kuin Niinistön. Haavistolle voi lahjoittaa osoitteessa: http://haavisto2012.fi/lahjoita/.

EU:n visioita hiilivapaudesta

Hupinsa kullakin, mutta minä olen hauskuuttanut itseäni perehtymällä EU komission "Energy roadmap 2050" visioihin. Koska kyseessä on pohjimmiltaan poliittinenraportti, ei siltä ehkä kannata odottaa kovin reipasta kriittisyyttä tai avomielisyyttä vaihtoehtoja kohtaan. Raportteihin on ennen kaikkea koottu vähän teknisempää tietoa konventionaalisen viisauden tueksi. Oma kokemukseni tällaisten raporttien lukemisesta (koskee muuten usein myös IEA:n raportteja) on se, että usein kiinnostavin tieto piilee numeroissa ja graafeissa. Tekstiin voidaan helposti ujuttaa liirumlaarumia, jolla numeroiden merkitystä kumotaan. Toki kriittinen pitää olla kaiken suhteen, mutta "Corporate bullshit":iä on vaikeampaa esittää numeroin. Lähtöoletukset ovat myös kriittisen tärkeitä. Se on nimittäin kohta josta käsin voi helpoimmin vaikuttaa analyysin lopputulokseen. Mikäli ideologia rajoittaa käytettäviä keinoja ja lähestymistapoja, niin lähtöoletukset on valittava ideologian mukaisiksi niin, ettemme vahingossa saa "vääriä vastauksia". Tässä joitain huomioita, jotka itsestäni tuntuivat tärkeiltä:

1. "Energy roadmap 2050"-pitää sisällään liudan eri dekarbonisaatio-skenaarioita, mutta on silmiinpistävää kuinka samanlaisia ne toistensa kanssa oikeastaan ovat. Referenssi-skenaariosta primäärienergian kulutuksen pitäisi laskea 30-40%, ydinvoimaa ei saa käyttää hiilipäästöjen vähentämiseen muuten kuin lähinnä siltä osin kuin sitä on jo olemassa ja tuuli-, aurinko- ja biovoimaa rakennetaan valtavasti lisää. Sähkön loppukulutus (s.23) kasvaa ja on kaikissa skenaarioissa melko samansuuruinen eli 5000TWh nurkilla. Koska skenaarioiden lähtöoletukset ovat melko samanlaisia, ei lienee yllättävää, että kustannukset eivät ole valtavan erilaisia.
2. Kaikissa dekarbonisaatioskenaarioissa oletetaan, että talous kasvaa (noin kaksinkertaiseksi vuoteen 2050 mennessä), mutta energiankulutus pienenee rajusti. Tätä uskoa ei perustella ja jo nyt EU on pahasti jäljessä itselleen  asettamista säästötavoitteistaan (s.10). Eikö malleihin kannattaisi rakentaa sisään oletuksia politiikan onnistumisesta perustuen siihen onko sitä noudatettu tähänkään asti?
3. Skenaarioissa oletetaan globaaleja päätöksiä fossiilisten kysynnän pienentämiseksi. Tämä heijastuu melko maltillisena fossiilisten hintakehityksenä. Missään ei mainita termiä "peak-oil" vaikka monet järkevät ihmiset arvelevat sen olevan käsillä jo tarkasteltavan ajanjakson alkupuolella.
4. Skenaarioiden numeronmurskaukseen on käytetty "PRIMES" mallia (mikä lienee, vaikuttaa muhevalta paketilta). Tähän malliin laitetaan sisään monien muiden asioiden lisäksi verot ja tukiaiset. Tässä on se riski, että sinänsä hyödyllinen päätöksenteon apuväline muuttuukin päätöksentekijän apuvälineeksi mikäli inputin poliittisia reunaehtoja ei varioida. Jos vaikka akustiselle energialle määritellään riittävän korkea tukiainen, niin aivan varmasti sitä rakennetaan, koska hulluhan se on, joka ei ota vastaan ilmaista rahaa. Jos taas haluamme ymmärtää valintojen kustannuksia yhteiskunnalle, on oletettua politiikkaa varioitava. Esimerkiksi olisi ollut mielenkiintoista lukea oikeasti teknologianeutraalista vaihtoehdosta, jossa reunaehdoksi asetetaan kasvihuonekaasupäästöjen vähennys, ohjauskeinoksi pelkkä hiilivero (lähteestä riippumatta) ja kaikki tukiaiset (mahdollisia tuotekehittelytukia lukuunottamatta) poistetaan. Nyt vaihtoehdottomuus on silmiinpistävää ja poliitisten valintojen kustannukset ovat siltä osin piilotettu.
5. Kaikissa skenaarioissa energiankustannukset nousevat rajusti.  Esimerkiksi  energialaskun odotetaan BKT:n noususta huolimatta nousevan nykyisestä noin 10% noin 15% tasolle (tai enemmän). Olen aikaisemmassa kirjoituksessani vertaillut tuota summaa joihinkin muihin yleisesti tärkeänä pidettyihin menoeriin ja todennut, että muutos on massiivinen. Koska EU:n raportissa valitun politiikan kustannuksia ei verrata vaihtoehtoihin, tämä kustannusten nousu esiintyy ikäänkuin vääjäämättömänä luonnonvoimana. Asiana jolle ei ole vaihtoehtoa. Tämähän on poliitikoille tuttu tekniikka, jossa omaa lemmikkivaihtoehtoa ajetaan vaihtoehtojen olemassaolo kieltäen, mutta jos haluamme keskustelun perustuvan asialliseen tietoon on tehtyjen valintojen kustannukset tehtävä selviksi. Esitetyissä skenaarioissa pääomakustannukset kapasiteetin asentamisesta olivat välillä 2000-3200 miljardia euroa (2010-2050). Sen sijaan fossiilisiin keskittyvä raportti arvioi pääomakustannuksiksi vuoteen 2030 mennessä KORKEINTAAN reilut 600 miljardia euroa (bau+ccs), josta ekstrapolaatio vuoteen 2050 antaa arvion 1200 miljardia (vaikka bau oletus antaa huomattavasti korkeamman sähkönkulutuksen). Tämä kustannusten nousu ei ole välttämätöntä vaan poliittinen valinta. Sellaisena se tulisi myös esittää ja niiden, jotka sitä haluavat tulee perustella miksi tämä tapa käyttää yhteisiä resursseja on muita arvokkaampi.
6. On syytä huomata, että raportin skenaarioissa rakennetaan massiivisesti myös fossiilisia polttavia voimalaitoksia, koska tuuli- ja aurinkovoiman tuotanto voi pudota lähes nollaan. Näin ollen tuossa aikaisemmassa kohdassa mainitut investoinnit sisältyvät jo suurelta osin dekarbonisaatio-skenaarioiden kustannuksiin. Ero syntyy siis ennen kaikkea kapasiteetin rakentamisesta moneen kertaan (HRES-skenaarion verkkokustannukset ovat lisäksi rajusti muita skenaarioita korkeampia). Numeerisesti tämän  voi nähdä tarkastelemalla suhdetta (asennettu kapasiteetti)/(keskikulutus). Nykytilanteessa se on noin 1.9, referenssi-skenaariossa 2.6, energiatehokkuus-skenaariossa 3 ja HRES-skenaariossa 3.8.
7. En oikein ymmärtänyt tuotantokapasiteetin rakennustahtia. Esim. referenssi-skenaariossa fossiilisia rakennetaan vuoteen 2030 mennessä 178GWe. Toisaalla taas huomautetaan, että vuoteen 2030 mennessä EU:sta poistuu ikääntymisen myötä yli 330GW fossiilista tehoa. Kuinka tämä alhainen uuden kapasiteetin rakennustahti on mahdollista etenkin kuin referenssi-skenaariossa fossiilisen kapasiteetin on tarkoitus nousta nykytasosta 179GW vuoteen 2050 mennessä? (Toisaalta referenssi-skenaariossa annettu rakennustahti implikoi, että uudella fossiilisella kapasiteetilla tuotetaan hiukan vähemmän sähköä kuin uudella uusiutuvalla kapasiteetilla. Tämä näyttänee kauniimmalta, mutta ehkä tuolle on joku järkevämpi selitys. Ydinvoiman kohdalla vanhan kapasiteetin uusiminen on laskettu uudelleen mukaan, joten kyllä sen minun ymmärtääkseni pitäisi olla mukana myös fossiilisten luvuissa.)
8. Tuulivoiman (selvästi raportin tärkein "uusiutuva" energianlähde) oletetut pääomakustannukset (s.67) ovat selvästi alhaisempia kuin IEA:n tai DOE:n vastaavat luvut. Toisaalta ydinvoiman pääomakustannukseksi laitetaan muita korkeampi arvio. Tämä olisi ehkä perusteltu mikäli esim. OL3 olisi tyypillinen projekti sen sijaan, että se olisi projektinhallinnoltaan sössitty prototyyppi. Raportin vertaisarvioijat huomauttivat samasta asiasta ja on hiukan kuvaavaa kuinka tämä lakaistaan maton alle toteamalla (s.6), että jos tuulivoiman pääomakustannuksia nostetaan niin silloin oppimiskäyrä voi vastaavasti olla jyrkempi. On siis melko ilmeistä, että kustannustaso halutaan postuloida tietyn suuruiseksi. Jos kustannus on liian korkea, niin sitä pidetään asiana joka korjautuu tukiaisilla ja poliittisella tahdolla. Minusta tässä edetään p...se edellä puuhun ja todennäköisyys hyvään lopputulokseen on heikko. Aurinkosähkön pääomakustannusten odotetaan putoavan kolmasosaan ja minkäänlaista keskustelua luonnon asettamista rajoituksista eri energianlähteille ei ole. (Jostain syystä näitä argumenttia oppimiskäyristä ja poliittisen tahdon tärkeydestä ei muuten yleensä sovelleta keskusteluun ydinvoiman kustannuksista. Se ei ilmeisesti ole kosher.)
9. Raportissa visioidaan massiivisesti nykyistä korkeampaa biomassan polttoa.Esimerkiksi uusiutuvia erityisen paljon korostava HRES-skenaario vaatii ehkä noin 500 miljoonaa kuutiota biomassaa. Mistä tämä kasa tulee ja mitkä sen korjaamiseen ekologiset ja sosiaaliset seuraukset ovat, ei keskustella lainkaan. (Bioenergia on myös ilmeisesti oletettu päästövapaaksi.)  Energiaviljelmille visoidaan riittäviä tukiaisia, joilla tämä tavoite saavutetaan ja jos sillä on on ikäviä seurausvaikutuksia vaikkapa globaaliin ruokahuoltoon, niin se on nyt sitten ilmeisesti no voi voi.
10. Kun tein nopeita testejä aikaisemmin kokoamillani tuuli- ja aurinkovoiman  tuotantotiedoilla ja mallinsin EU:n vuosittaista sähkönkulutusta Iso-Britannian kulutusprofiililla, totesin referenssi-skenaarion olevan ehkä mahdollisuuksien rajoissa. Siinä luotettavaa kapasiteettia (katso s.23-24) on juuri ja juuri riittävästi kompensoimaan satunnaisen tuotannon katoaminen. Sen sijaan en ymmärrä kuinka esim. uusiutuvia täynnä olevan HRES-skenaarion voi saada toimimaan. Näytän ohessa simuloidun kulutuksen, satunnaisen-uusiutuvan tuotannon ja niihin liittyvät pysyvyyskäyrät (duration curves).Minulla on useita ongelmia tämän ymmärtämisessä. Ensinnäkin skenaariossa on luotettavaa kapasiteettia noin 600GW, mutta vuoden kuluessa maksimitarve on yli 800GW. Siellä näyttäisi siis olevan melko massiivinen 200 GW reikä luotettavassa kapasiteetissa. Toisekseen skenaariossa ylituotannon suuruus voi olla melkein 700GW eli enemmän kuin EU:n keskikulutus! Raportissa puhuttiin lyhyesti siitä kuinka ylijäämäsähköllä tehtäisiin vedestä vetyä, joka lisättäisiin (max 30%) maakaasuputkistoon, mutta on ilmeistä että 700GW:n elektrolyysilaitosten kustannuksia ei oltu laskettu pääomakustannuksiin mukaan. Samoin vedyn alhaisempi energiatiheys tarkoittaa huomattavasti alhaisempia energiansiirtomääriä maakaasuputkistoissa. (Jos esim. Nordstream kaasuputki voi siirtää 63GW teholla primäärienergiaa, niin siitä vedylle varattavaan osaan mahtuu ehkä alle 6GW. Joku kiinnostunut voi laskea tuon tarkemmin.) Kolmanneksi, koska ylituotantoa on niin paljon, en ymmärrä kuinka laskuissa on voitu olettaa tuuli- ja aurinkovoiman kapasiteettitekijöiksi melkein samat luvut kuin esim. referenssi-skenaariossa. Energianvarastoinnista puhutaan ylipäätään hyvin ympäripyöreästi. Neljänneksi, skenaariossa jäljellä olevan ydinvoiman kapasiteettitekijä on 0.50. Miksi?  Ei ole mitään järkeä ajaa ydinvoimaa noin alhaisella kapasiteettitekijällä. Pysyvyyskäyrä antaa muuten ymmärtää, että kun kulutuksesta on vähennetty tuuli- ja aurinkovoiman osuus, maksimi kapasiteettitekijä olisi noin 80%. (Raportista voi kyllä lukea rivien välistä, että tämä skenaario on tekijöidensäkin mielestä epärealistinen.)
11. Koko järjestelmä rakennetaan erilaisten tukiaisrakennelmien varaan. Yleisenä ongelmana haluaisin kysyä minkälainen vaikutus prosyklisellä politiikalla on energiainfrastruktuuriin? Tukiaisiin on paremmin varaa, kun talous kasvaa, mutta ne ovat ilmeisimpiä leikkausten kohteita, kun valtioiden pitää tasapainottaa budjettinsa. Boom-bust-syklit varmasti aiheuttavat energiapolitiikassa samanlaista tuhoa kuin asuntomarkkinoillakin. Koko raportti on kirjoitettu ikään kuin EU:n velkakriisiä ei olisi olemassakaan.
    

    

    Kuva 1: simuloitu EU:n sähkönkulutus ja tuuli- ja aurinkovoiman tuotanto HRES skenaariossa.
    

    

    Kuva2: Kuvan 1 tiedoista johdettuja pysyvyyskäyriä HRES-skenaarioon.

    
    

    
    

    
    

Trying to understand system wide costs of energy

Some time ago in Brave New Climate Peter Lang wrote an interesting post on the CO2 abatement costs in Australia. He found that nuclear power is not the cheapest abatement method under Australian circumstances. His post was followed by interesting discussion and several wondered that can one arrive at sufficiently decarbonized electricity supply by always choosing the lowest cost alternative, should we not only include options that actually get all the emissions reductions we need, and what is the proper way to account for and discount costs. Since I have wanted to understand cost calculations better for quite some time, I decided to use this problem as one of my own exercises. For background you might want to read my earlier postings on related things (here and here, or in finnish here and here). Here I attempt to sketch system wide cost and CO2 abatement consequences of wind and nuclear based options. (In case you want to play and have access to Matlab, you can download some poorly documented macros I used.)

Throughout I will use the discount rate of 7.5%, a payback period of 20 years for wind power, 50 years for hydro and nuclear (this is longer than usual, but assumption is not hugely important for my needs), and 40 years for natural gas and coal. I won't bother to list all the input parameters here, but most of them I have picked up from the typical market prices for different fuels as well as from the National Renewable energy laboratory. As a calibration I find following levelized costs of energy:

Source	Capacity factor	LCOE ($/kWh)
Coal	0.85	0.066
Gas	0.85	0.071
Wind	0.29	0.102
Hydro	0.5	0.046
Nuclear	0.9	0.063

Few remarks are in order. There is no single LCOE since the costs are different in different places and different cost components keep changing. In Asia, for example, the costs of nuclear can be considerably lower than the above estimate, but under American style regulatory framework maybe higher. For gas prices I used a value of 8$/MMBtu. This is higher than the current gas prices in US, but lower than the European ones. The LCOE for wind power is lower than the typical feed-in tariffs in Europe and electricity spot price in the Nordic region fluctuates around 7.5 cents/kWh. The fact that Finnish utilities want to build nuclear power also suggests that compared with alternatives economics for it are favorable in our circumstances. Changing the assumptions can of course change the above values somewhat, but overall I think the numbers pass the sanity check. In what is to follow the figures above are not even that important since they mainly set the starting point and after that the cost trends are determined by the changing energy mix and the capacity factors.

I will now compare two different scenarios for decarbonizing the electricity supply. In the first scenario we start with the fossil fuel dominated system where coal provides baseload power corresponding to the minimum yearly demand (as before I take the demand pattern from the Bonneville power authority load). I make drastic approximation that the output power of coal burning power plants does not vary at all and that the load following is only done with hydro (with capacity of 15% of average demand) and natural gas. Somewhat unrealistically I also assume that the hydrocapacity is always available. (This assumption makes the systems appear to have somewhat lower emissions than in reality where hydro power might have a capacity factor of around 50%.) I then start increasing the amount of electricity generated with wind. The production profile of wind power is derived from combining the Irish, south-eastern Australian, and Bonneville power authority wind production. The details are explained in an earlier posting. The wind production is taken to have a priority access to the grid. To generate the remaining electricity, we use coal at a power corresponding to the minimum demand once the contribution of wind power has been subtracted from the demand. The rest is generated with hydro and natural gas in that order. I further assume that production can always respond so rapidly that no capacity has to be in the spinning mode. (Our imaginary state has an average demand of 10000MW.)  In the first movie, I demonstrate how the mix of different sources of electricity evolve under this scenario.

In the second scenario the starting point is the same, but rather than increasing the amount of wind power, we increase the amount of nuclear power. Like coal, this nuclear power is taken to produce constant power so that it first displaces baseload coal and then starts replacing natural gas. When nuclear power starts to replace gas used for load following its capacity factor starts to take a hit. The 2nd movie illustrates the mix of different sources of electricity in this scenario.

These two scenarios are naturally not the only ways to satisfy electricity demand, but they are possible ways and with the numbers shown in the movies production always matches demand. Since the required capacities and capacity factors change with increasing wind or nuclear penetrations, the LCOE for different sources do not stay the same. For the society (although not necessarily for the individual investor) what matters most is the cost of typical kWh rather than the LCOE for each individual component of the electricity supply. I will take the cost of typical kWh to be the weighted average of each separate LCOE. The weights are given by the relative amounts of electricity produced from each source.

I think one clear error in what I do, is to implicitly assume that the underlying energy infrastructure stays the same over the payback period. As we decarbonize the electricity generation, capacities and capacity factors change with time and this should, in principle, be taken into account. On the other hand, since we do not live in a planned economy postulating construction plans decades in advance would also be dubious. The best the society might be able to do, is to try to reduce uncertainty and ensure that the market pressures always act in the right direction of ever lower GHG emissions.

So what do I find? In Figure 1, I summarize how the system evolves under the first scenario while Figure 2 summarizes the costs involved. For the wind based solution increasing share of wind power first lowers the space occupied by the base load power plants. This implies shutting down coal power plants and replacing them with gas plants.If methane leakage is bravely assumed not to be an issue, at this phase some CO2 emissions are avoided due to swapping for somewhat cleaner fuel. At higher penetrations capacity factors of wind, gas, and hydro power are reduced and costs continue to increase. (Btw. Getting someone to invest in new gas infrastructure might be tricky if the investors expect the demand growth early on the decarbonization path to be short lived. Presumably they do not believe this to be the case which, if accurate, would be bad news for the climate.) Even with very large wind power capacity one needs a reliable backup that can produce almost all the power consumed. For this reason after rapid rise in the capacity of power plants burning natural gas, their capacity declines only very slowly with increasing wind penetration.

Figure 1: Capacities, capacity factors, and the share of fossil fuels as the fraction of wind generated electricity increase.

Figure 2: LCOE under the wind based scenario.

For the nuclear based scenario 2, the corresponding results are shown in Figures 3 and 4. Now the system wide LCOE actually decreases slightly until nuclear power produces around 75% of the demand (at this point around 10% is produced with natural gas). After this the cost increases with the reduced capacity factors in NPPs. However, the kind of cost escalation apparent in the wind power based solution is absent since there is no need to maintain large amounts of reliable capacity running at low capacity factors. In these examples I made no assumptions about learning curves. If the capital costs of nuclear power are reduced by about 10% for each doubling in capacity until 10000MW (around 30% reduction in capital costs in total), the final LCOE of the decarbonized system is actually lower than the starting point. Similar cost reductions of wind power over the decarbonizing pathway used here do not avoid escalation of costs since cost increases are largely caused by the reduced capacity factors. It seems that one can also make a plausible case that the increased cost at high nuclear penetrations is an artifact of the simplifying assumptions I made. Eventually smart grid solutions can increase the share of base load power, NPPs can load follow, and lower capital cost NPPs which are better suited for load following can be engineered.

Figure 3: Capacities, capacity factors, and the share of fossil fuels as the fraction of nuclear generated electricity increase.

Figure 4: LCOE under the second scenario.

Finally in Figure 5, I compare the most relevant metrics of both scenarios. The costs diverge dramatically with the fraction of chosen carbon free energy. Nuclear based solution ends up with fairly constant LCOE over the pathway leading to decarbonization, while costs escalate with wind based solution. The installed carbon free capacity is drastically higher in wind based solution, suggesting greater challenges in construction and grid design. Finally, the fraction of electricity generated from fossil fuels is higher in the wind based solution. Together with increasing costs this implies dramatically lower "bang for the buck" at large wind penetrations. In contrast by the time nuclear power produces the same amount of electricity as the yearly demand, share of fossil fuels has dropped to less than 2%.

Figure 5: Comparison between wind and nuclear based scenarios.

It should be noted that in the above in addition to many simplifying assumptions I ignored the additional transmissions costs for the wind based scenario. I am quite clueless as to what kind of grid upgrades are needed, but it seems clear that with wind capacity in excess of 5 times the average demand changes would be substantial. Where I live the transmission costs amount to around one third of my electricity bill so changes in transmission costs would have a large impact on the cost of electricity.

In this post I also focus on electricity production only. To decarbonize our societies we will also have to decarbonize heating and transport. If we were to use excess wind power to heat water, it is easy to see that the rise in the cost of warm water would be even greater than the cost increases in electricity (home work exercise). In case of nuclear power warm water could be a by-product of electricity generation (although this reduces the electrical power somewhat). Furthermore, if this warm water is produced close to the wind turbines, transporting it to consumers will cost more than moving electricity around. Similar conclusions apply for liquid fuels.

Do these kind of cost differences matter? I find it shocking that so many (typically wealthy westerners) seem to have an attitude that energy costs are almost irrelevant and that the question is basically analogous with a choice of buying a PC or a Mac. Some even seem to view rising energy costs as a good thing. We spend roughly 8% of our GDP on energy and this energy use pretty much makes all the rest possible. It is useful to remind how much we actually spend on some things that are widely valued. I will take the figures from my home country of Finland, but they are probably quite representative of industrialized countries in general.

Spending on	Share of GDP
Public health care	7%
Education	6%
Pensions	12%
Pensions (2030 esimate)	15%
Development aid	0.5%
Ministry of environment	<0.2%

In the past few decades the income differences have increased also in Finland so that today our richest 10% have around 2-3% greater share of the GDP than in 1990. My impression is that most environmentalists find this terrible. The aging population causes our pension costs to increase and this increase is cause of anxiety for many both left and right. So we can very easily see that the energy costs in our society are comparable to many big spending categories for which it is already hard to find resources. Large increases in energy costs can easily have far greater social consequences than most people probably realize. Fantasizing that this is something to be promoted not only borders on insane, but is morally dubious. I have yet to find an explanation for why a society that spends more on energy rather than, for example, on education and health care is a better place for its inhabitants?

You might try to rescue the fantasy by somehow assuming that the same GDP could be produced with so much lower energy consumption that the total costs remain the same. However, as is clear from the above estimates this would require so drastic reductions in energy use that it cannot be taken seriously as a basis for responsible climate policy. There is nothing to suggest that this is doable and especially in the case of poorer countries that this is desirable. (Also, why would economically justified energy savings measures be incompatible with nuclear power is not clear to me.)  Once the discussion strays into this territory, I often end up confused by the inconsistency of the arguments in favor of the paleogreen consensus. Construction of ideologically favored energy sources is typically touted (not entirely convincingly) as being good for the economy, but the same people might in a different context condemn economic growth and express desire for degrowth. Which one is it? Surely one cannot have it both ways?

Do I seriously believe that the societies will choose the path of ever increasing energy costs? Of course not. As soon as the effects of cost increases become apparent and start to affect other priorities people have, different choices will be made. As I see it, choosing the wrong way initially implies wasteful spending and unnecessary CO2 emissions since it delays the day when we eventually do choose policies that can eliminate the GHG emissions from the energy sector for good.

Venäjän vaalit :-(

 Venäjän vaalit ovat osoittautuneet ilmiselvän epärehellisiksi. Putinin "Yhtenäinen Venäjä"-puolueen ääniosuus nousee äänestysalueen äänestysprosentin mukana ja Tsetseniassa melkein kaikki ovat äänestäneet Putinin puoluetta. Puolueen ääniosuudet eri vaalipiireissä taas sattuvat piikittymään kivasti pyöreille prosenttiluvuille. Hiukan hämmentyneeltä vaikuttaa myös kuvan toimittaja...

Meillä vaalitulosta on kommentoinut mm. pääministeri Katainen, joka "uskoo, että jatkossa Venäjää hallitsevien poliitikkojen pitää entistä paremmin perustella kantojaan tavallisille venäläisille ja ottaa huomioon kansan mielipide." EU:n kannanotto on melkein yhtä jämäkkä. EU valittaa puutteellisista vaalijärjestelyistä ja toivoo homman sujuvan maaliskuun presidentinvaaleissa paremmin. USA ainakin toteaa ilmiselvän ja ei pidä vaaleja sen enempää vapaina kuin oikeudenmukaisinakaan. Ei Venäjä ole tänä päivänä demokratia eikä sitä pitäisi sellaisena keinotekoisesti kohdella.

Lisäys 09.12.2011: Anton Nikolenko kirjoitti samasta teemasta hienon postauksen.

Solar combined with wind power: a way to get rid of fossil fuels?

Earlier, I wrote on how crucially an unreliable sources of power such as wind depend on fossil fuels. Based on real world production data from around the world, I noted that even with massively distributed production wind power is very variable and necessitates a reliable backup power source (typically from fossil fuels) which must be able to produce essentially all the power society consumes. A way around this problem would be a massive energy storage, but I found the size of the required storage to be unreasonably large.

One typical response to findings such as these, is to brush them aside by claiming that even if true, the results will not matter since we will have many different renewable energy sources acting together (as if there is some "harmony" in two essentially random signals). Most importantly quite a few people base their vision of future energy production on a mixture of wind and solar power. For this reason I felt the need to return to this problem so that also solar power is considered. Unfortunately, I have yet to find a good source for real world production data for solar power. The best I have come up with are images (typically of the daily production), but raw data is better hidden.

However, since solar power (without storage) production is proportional to insolation we can use meteorological data as a reasonable starting point. US has a National solar radiation database which has large collection of insolation modelling data around USA. From this data they have also formed a "typical meteorological year 3 (TMY3)" datasets. (There are some quirks in the construction of TMY3 that I frown upon. For example, after El Chichón and Mount Pinatubo eruptions insolation was reduced, but these periods were apparently excluded from the TMY3 as atypical. Of course they were atypical, but they are still things that do happen and whose effects must be considered. However, I suspect that the effect due to eruptions was still minor in US.) As my insolation data I take the average of TMY3 data from six different class I sites (class I has the best data) in three different states: Prescott Love and Tucson Airport in Arizona, Arcata Airport and Fresno Yosemite Airport in California, and Denver Airport and Limon in Colorado. These sites have an average latitude similar to southern Spain.(Why did I choose these sites? Well, being lazy I started from the entries listed in alphabetical order by states and picked the first southern states I encountered.)

Somewhat annoyingly only hourly data is provided. We know from BNC among others that solar power (especially PV) can have large swings on shorter timescales. Therefore, this limitation may have important consequences. Nevertheless, let us ignore the torpedoes with an understanding that the solar power we talk about here is such that sufficient storage has been already implemented to smooth out hourly variation in production. So keep in mind, that the starting assumptions for solar production have a bias towards the optimistic side. Since the production data for wind power is given every 5 minutes I will linearly interpolate the solar insolation data to deduce the production of solar power every 5 minutes (link to the data here). As in the earlier study the data corresponds to one year starting July the 1st. and the consumption data corresponds to the Bonneville Power Authority load with a possible scale factors to suit my needs.

Now that we have rather massively distributed production of both wind and solar power, what do we find? In Fig. 1 I show the average insolation from six US locations (the wind data I have discussed earlier). Daily variation is apparent as is also the large seasonal variation between summer and winter. In this system the solar power has an impressive 20% capacity factor. OK, now that we have the relevant data let us then proceed to check what backup requirements we have if we are to integrate this solar production in such away that production and consumption match (as they must).

Figure 1: The average insolation as an average over 6 sites in USA. The figure shows both the yearly data as well as an example of one random 7 day period.

If we choose the installed solar capacity such that the solar power produces the same amount of electricity over the year as our model society consumes, we find that a massive 55% percent of the electricity is generated with reliables (typically fossil fuels). These reliable power plants must be able to produce 97% of peak demand and they are running at a capacity factor of 36%. Solar power itself sees its capacity factor drop to 9%. These results are essentially caused by the seasonal variation of insolation (too little production in the winter) and the fact that solar power reliably produces nothing when it is dark. It is perhaps not worth pointing out that this scenario is not compatible with the goal of decarbonizing our societies.

How about mixing solar and wind? Since the sun shines during the day when consumption is higher one can guess that unreliables production matches the consumption better if there is some amount of solar in the mix. On the other hand the solar output varies even more than the wind output since, unlike wind, it predictably produces nothing when it is dark. (Of course, if the sun stops shining for good, eventually the winds disappear as well.) So presumably one shouldn't push the fraction of solar production too high. This suggests some "sweet spot" for the fraction of installed solar capacity if we are to match the production of wind and solar optimally to consumption.

Figure 2: How well the solar and wind production match the consumption as a function of solar capacity.

 In Fig. 2 I show how the function
Σ(Production-Consumption)²/Σ Production²
behaves. If production matches the consumption exactly (as it does in the real world), this function vanishes. We note that optimally the installed solar capacity should be about 21% of the installed wind capacity. (Not that this split gives rise to production which matches consumption. It is just somewhat less worse than other choices.)

For comparison, European renewable energy council and Greenpeace postulate a more ecumenical figure close to 50/50 for the split between wind and solar. (Since no explanation for this split was apparent, cynic in me is left wondering if this choice simply reflects the relative turnovers of respective industries which presumably correlate with spending on lobbyist.) However, if we are to use such a mix and produce as much power with wind and solar as we consume, it turns out that we need reliable power plants with a capacity of 91% of peak demand. They will have a capacity factor of 17% and amount to 24% of total production. Combined capacity factor of wind and solar has now dropped to around 19%. This case is presented in Figs. 3 and 4. In my earlier study with just wind power I found that fossil fuel power plants accounted for 21% of production (and with a capacity 88% of peak demand). So adding this much solar into the system has actually made things worse! The culprit is again the seasonal variation of insolation which reaches minimum during the winter (in northern hemisphere) when the consumption is often greater.

Figure 3: A snapshot of the production and consumption during a one week interval when solar and wind capacities were equal.

Figure 4: The yearly production and consumption together with the reliables output when solar and wind capacities were equal.

<sup>(As an aside: Another way to understand the challenges involved is to compare standard deviations relative to mean for wind and solar production as well as for the consumption. For the consumption this number is around 0.15, for wind power it is much larger 0.47, and for solar power it is huge 1.32. However, keep in mind that the underlying distributions are anything but normal. They cannot really be described properly by just the mean and standard deviation.)

How about choosing the solar capacity to be the "optimal" 0.21 of wind power capacity? Then we need reliable power plants with a capacity of 89% of peak demand. They will have a capacity factor of 14% and amount to 19% of total production. So, yes! Adding solar power to the mix can sometimes help, by reducing the electricity produced with fossil fuels from 21% to 19%. Unfortunately, the required capacity of reliable power plants is actually slightly higher than with wind only. I will not dare to compute the cost of CO2 abatement under such a scenario.</sup>

Figure 5: Solar capacity is 21% of the wind capacity. Weekly snapshot.

Figure 6: Solar capacity is 21% of the wind capacity. Yearly data.

Finally, few words about storage. Maybe adding solar into the mix would help us to live with a smaller energy storage? Unfortunately, also that hope is misplaced. Due to seasonal variation systems with solar power actually need MORE storage. In the earlier study with only wind power I estimated that in order phase out fossil fuels AND keep the lights on, we need an energy storage for about 9% of yearly production. Repeating the exercise (storage doesn't decay and 20% round trip loss) for the system combining wind and solar, we find that we need storage for 13% of production in the 50/50 case while about 10% is enough with solar capacity limited to 21% of wind capacity. (Also, in the 50/50 scenario we would have to be able to store energy at a rate which is nearly 2.5 times the average power consumption of the surrounding society. Otherwise capacity factors are reduced and/or dependence on reliables reappear.)

To conclude, I note that adding solar power and wind without massive storage to the mix does next to nothing to remove the need for fossil fuel based energy infrastructure. Scenarios based on wind and solar power are fundamentally reliant on fossil fuels and sooner this is understood the better it is for climate. Currently the mirage of purely unreliables based energy production essentially maintains the use of fossil fuels for as long as the eye can see both for technical and financial reasons.

While doing these exercises I occasionally get a feeling that I am fencing with a tetraplegic. You might say this is not sportsmanlike, but unfortunately the political reality is that the mirage of solar and wind based solutions is a tetraplegic which hampers us from confronting the real and difficult issues with respect to climate change. By offering an easy "alternative" this mirage effectively acts as a cover for the damage anti-nuclear activities are causing for attempts to mitigate climate change. Unfortunately fencing must continue since this cover must be removed.

David Graeber: Debt: The First 5,000 Years

Luin amerikkalaisen antropologin David Graeberin kirjan "Debt: The First 5,000 Years" ja suosittelen sitä lämpimästi. Kirjoittaja on anarkisti pienellä a:lla ja (mutta?) hyvin järkevä. Tämä oli niitä kirjoja, joiden koin avartavan mieltäni mukavasti. Lähtökohtaisesti Graeber ei kuvia kumartele eikä epäröi todeta esimerkiksi monia taloustieteen lähtökohtia utopistisiksi myyteiksi. Oli erityisen hienoa, kun hän kertoi velan, rahan ja yhteisön yhteyksistä muissa kulttuureissa. Kun elämme omassa kulttuurissamme, opimme pitämään monia asioita niin itsestäänselvyyksinä, että emme edes huomaa kuinka erikoisia ne ovat. Silloinkin, kun kyseenalaistamme asioita niin nämä "itsestäänselvyydet" asettavat omat reunaehtonsa sille millaisessa viitekehyksessä kaikki keskustelu tapahtuu.

Debt: The First 5,000 Years by David Graeber

My rating: 4 of 5 stars


Wow! This one was really good, but read carefully since it might broaden your mind. He discusses very clearly not only history of debt, but also of money, power, and how perceptions on these issues have been strongly shaped by cultural backgrounds. Many things that he points out have become so "obvious" to us that we no longer even see how strange they actually are.



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