This talk was held on Facebook Live on the 30th of March 2020 under the quite straightforward title: “Sustainability talks: The limits of renewable energy”. It was originally meant to be a live talk hosted by the Repair Café in Odense, but the Coronavirus lockdown decided to challenge our creativity and technological literacy, forcing us to host the event online instead.
All in all, apart from the fact that I got to interact (if only by Facebook comments) with other human beings after three weeks of self-isolation, I was really impressed by the interest and engagement of the public, which I would like to thank again. But enough said, get the video started to listen to what I had to waffle about. Below the video you’ll find the questions asked during the talk and the answers to those I didn’t have the time to address in the talk itself.
(Hint: you can start at 02:15 to skip the painful setup process)
Q&A
Note that you could probably have a whole presentation in itself on each of these questions, so I’ve tried to be brief but to the point. Be aware that I’m also only answering to the best of my knowledge (while trying to be more or less coherent and rational of course :P).
Can you talk about this change in consumption?
This is THE big question which every government or policy maker would like to have answered, so all I can do is give suggestions and personal experiences. And honestly, I think this is the best answer we can give: if consumption is driven by individuals, then there’s no general solution, which is the nightmare of centralised governments. That’s also in my opinion why the power industry, which until recently mainly had big centralised players, was the first one to get decarbonised. Transports on the other hand are lagging behind because they depend so much on individual commuter’s specific driving patterns, and are therefore so hard to centrally control.
That being said, what I mean by “a change in consumption” is that if consumption is governed by what renewables can supply to us, we will inevitably be limited in our choices. For example, if planes were forced to fly on biofuels instead of fossil fuels, even with a mature biomass industry there would be no way to physically sustain our current rate of flights. Flights would become a lot less frequent and therefore more expensive. People will shout that this goes against principles of democratisation of travelling. But isn’t it rather that we’ve lost all sense of the value of travelling? (I invite you to check out the “Nirvana through Corona” post on this blog for more reflections on the topic).
I for one am a massive fan of triathlon, and at this time of the year (early spring), it is typical for teams (especially from the colder parts of Europe) to go on a week-long training camp in Mallorca, admittedly more for the scenic bike routes than the tan lines (well, well…) . But this is only possible because RyanAir and co allow to get there and back for less than a food shop at the supermarket. If flights were a lot less accessible, I think most teams in Denmark would find that a week of cross-country ski training in Sweden instead would be just as fun, just as cardio-intensive, (if you’re lucky) just as sunny and most of all a whole lot more eco-friendly.
Do you have any orders of magnitude wrt CO2 emissions throughout the whole life-cycle?
I’m not gonna lie, I didn’t have numbers on top of my head, but the table on page 1335 of this IPCC annex gives a very useful inter-technology comparison in gCO2eq/kWh taking into account the whole lifecyle (but it seems to be without recycling, interestingly enough!). As always with life cycle analyses, the hard question is always where to draw the line on what emissions to count or not. Emissions also depend on where, how, by whom the technology is deployed, but in general according to this annex:
Wind (~11 gCO2eq/kWh) and solar (~ 48 gCO2eq/kWh) can have a fairly clean conscience compared to the classic dirty ol’ coal (~820 gCO2eq/kWh) and even combined cycle gas (~ 490 gCO2eq/kWh) industries.
Do we make progress on the issue of stocking renewable energy ?
The problem with storage is that it involves transformation of energy from one form to another, and therefore inevitable losses (hydrogen production being the most flagrant example). As satisfying our demand entirely from renewables is already going to be a close call, we have to make sure to use most of it when it is produced. This calls for more “flexible” consumption, and demand adapting to supply, instead of the other way around. Examples are “smart” homes that plan consumption, planned electric vehicle charging, etc…
But of course, we will still need some storage, and I would summarise the existing solutions like that:
-Hydro power pumping remains the most common solution at large scale, but is restricted to countries which have the adequate geology. A cool project is the link being built between Scotland and Norway to store the excess Scottish wind power behind Norwegian dams
-thermal “storage” is however also a very interesting solution. Unlike electricity, which is immediate, heat takes a certain time to dissipate. The Danish use CHP (Combined Heat and Power) stations to cope with the high share of wind (>40%!!!) in their grid: when wind blows, these power plants (which run on biomass, waste, or whatever you want) reduce their electricity consumption and just produce heat, which is redistributed to the households through district heating. When there is less wind, these CHP plants use more of the heat to produce electricity, and less is redistributed to the households. In a sense, the heat production acts as “buffer” for the variable electricity production. Long-term thermal storage in specific materials (stones) is also being experimented and is worth following closely
-batteries grab most of the media’s attention nowadays, and are making incredible progress in terms of efficiency, lifetime, material usage, but I think they will remain specific to certain applications (eg. private electric vehicles), as large scale storage is not feasible
-a lot of talks are also happening with regards to hydrogen, but as I said, producing the fuel and reconverting it back to electricity in the car would leave you with a ~ 36% overall conversion efficiency, which only really makes sense in very specific applications where you have no other choice.
So I think there still isn’t and won’t be any clear winner in the future, but I believe we can solve the intermittency problem at least on the time scale of up to a few weeks of storage. The real problem is the seasonal variability over the year, and the only solution I see for this is to adapt our lifestyle to each season (our move to the equator!).
Is a “rebound effect” likely? Where people will consume more because it is seen to be “cleaner”?
Answered (partly) in the video at 43:58.
Regarding the rebound effect due to the “cleaner” ressource, I don’t really see it as a major problem. On the contrary, I feel the rebound effect at the moment is happening because people don’t really think about where their energy is coming from. I mean…electricity is generated by electric plugs, right?
Regarding the transportation of raw materials, is it possible to keep all the processes (mining, transport…) in Europe, to avoid imports from other continents? (especially metals, panels, concrete)
To answer that, I’ll boil down these materials into their main components:
-the steel used in the wind turbine towers and the structural frames of solar panels is highly recyclable. If Europe manages to reduce its consumption as would be needed to match the supply by renewables, a lot of the steel used in obsolete infrastructure could be reused for the further development of renewables. Attention should be paid to the quality (strength, stiffness) of the recycled steel, as it depends on the ratio of raw iron to added additives (coke being the main one, which is essentially processed coal, hum hum)
-Silicon-based PV panels, which are currently the most common ones out there, are based on silicon, produced out of sand. Sand wasn’t particularly perceived as a rare element until now, however its ubiquitous use in our society has driven it to become a more and more precious resource. Which shows the extent to which our current consumption models put stress on the most basic of nature’s resources.
-Concrete is simply a mixture of aggregates (see comment on sand for silicon), water and cement. Cement in itself is made out of limestone, chalk or clay, heated up and grinded at very high temperatures. While these basic materials are quite common, it is the very high temperatures at which they are processed which are a problem, as they are very energy and therefore emission-intensive. Cement is therefore more of an energy than a ressource problem.
The stock issues we see on a shorter term concern rare earth elements such as a the ones presented, which are really absent from Europe, but with a bit of luck innovative technology and design can find alternatives to those.
Again, I’m not a materials expert, so there might be some much more clever ways to go about this nowadays. But I think in general it is interesting to look at Europe’s reusable resources rather than its raw resources.
Thoughts on carbon taxing?
I think carbon taxing is definitely necessary to get things changing and has to be considerably increased compared to current levels, however the big question is how to implement it while staying socially fair. When you see the Yellow Vest mouvement in France which originally emerged from an increase in fuel prices, you realise some people really can’t afford to pay more on heavily fossil fuel-dependent goods. Taxes and restrictive regulations are in my opinion best suited to regulate and optimise the functioning of existing systems. However, alternative systems also have to emerge on the side, which are a lot less dependent on fossil fuels (short food circuits, local employment and tourism…) and which are based on incentives rather than fines.
But again, this is a topic up for debate and still extensively researched, so I’ll keep my eyes out for answers as well.
Hi Nicolas, you mentioned about how society is better at being more environmentally friendly when laws/regulations are put in place – what practical laws would you recommend governments put in place to help reduce consumption and enhance everybody’s individual environmental responsibility?
I am having a particularly hard time answering in a concise way to this question, as this is very close to my PhD topic and I have a tooooooooon to say. I’ll try to make it short.
First of all, more and more people (especially younger generations who’ve only known democracy) point towards the advantages of “green” authoritarianism to meet sustainability targets. Sure enough, the strict measures of Coronavirus quarantines have helped significantly reduce emissions over the past few weeks, but I don’t think restricting our liberties to that point is something we should strive for.
As you correctly put, regulations should instead help/encourage consumption reduction, and in our current society this usually goes through economic incentives / disincentives:
-planes nowadays still fly without taxation on kerosene, which allows them to offer these ridiculously low prices. How can short distance European flights be cheaper than the same distance by train !? There definitely needs to be higher investments in our rail system, for one. Only then will individuals be able to make the right environmentally friendly transportation choices
-consumers should also be made a lot more aware of the daily energy they are consuming: this could be indicated on products you buy along with the price tag. Installing meters in households also allows consumers to see that toasting bread or using a hair drier uses an incredible amount of energy compared to other household applications and makes them think about the impact of their daily actions.
But the main issue for governments is that individuals, unlike industries, are not only economically driven and have more irrational, diverse and unpredictable behaviour. And this is why applying regulations directly to individuals is hard, and this is also why most regulations focus typically on industries with centralised activities.
By pushing for more renewables, we’re in a situation where it is not governmental regulations which restrict our choices, but the rigid laws of physics, and therefore we have to adapt our lifestyles no matter what.
Some points from what I know:
– In France, many installation projects are stopped for security reasons by the air force, as they might prevent low altitude flights
– Energy transportation remains a huge deal which does not have any good answer for now
– Many people living close to such windfarms complain about the noise produced. I do not know if it’s true, but what could be the improvements in the near future ?
I’ll answer to points 1 and 3, because point 2 will just increase the size of this post by a tenfold. Regarding wind farms near airfields, they are indeed a problem as according to regulation they represent an obstacle along planes’ take-off and landing paths. Additionally, they create turbulent wakes up to several hundreds of meters above the rotors, especially for large wind farm arrays. However, current regulations are considered too strict and in Germany debates are under process to reduce the exclusion zone.
Regarding noise, I’m afraid this is a legacy from the very first prototypes in the 70s-80s which has been transformed into a popular belief the industry has struggled to get rid of. Indeed, the much smaller turbines back then had a much higher rpm (rounds per minute), which made the swishing sound of the blades quite loud. Since then, larger turbines have lowered their rpm, improved the aerodynamics of the blade tips to reduce vortex shedding, and improved the gear mechanism in the nacelle to make it more smooth. It turns out that wind turbine noise measurements have to filter out noises from nearby road traffic or wind in the trees to identify the impact of turbines. And frankly, whenever I walk under turbines I can barely hear them myself, although I’m not quite deaf yet.
Another issue to take into account is the “shadow flicker effect”, where the shadows from the rotating blades can be a nuisance for nearby residents, especially when the sun is low. However, most wind farm planning software nowadays take this into account, and make sure our farmers can go to sleep undisturbed, to the soft sound of nearby passing cars on the country roads.
Do you have an estimate on how much run time years you have to deduct for recycling from the overall energy producing years?
Quite frankly, no. It definitely will depend on your recycling method. For wind turbines, if you mechanically grind the components to use them as new building materials (concrete aggregate from foundations, blades parts for cement production or structural elements), this will not use much energy and could even be counted as emissions for their next use instead of the turbine’s. Blade thermal treatment will use a lot more.
The high heats required to recycle solar panels will also require energy-intensive methods. Note also that a temperature of 500C requires high-grade heat, so you cannot just use recycled industrial waste heat, which is an additional challenge.
But I will definitely keep my eyes out for more specific numbers!
Can the blades be “refurbished” and reused?
Answer in the video at 41:15.
Is consumption reduction on a global scale realistic with increasing population and without keeping the majority of the world population in poverty? What makes us believe that the transition towards a sustainable future will be easier in these countries and free of dominance (in terms of market)?
Answered in the video at 45:44.
How does the short lifetime imply fast learning curve?
Answered in the video at 50:10.
What do you think about nuclear energy, What about fission vs fusion?
Answered in the video at 51:45.
Last but not least, an interesting conversation from the chat:
Lea: Europe do not have any rare eath material ores...
Nicolas: Very good point Lea, and I think that’s why we need to rethink the design of our technologies to not only make them more efficient, but also give us more energy independence. It would be a shame to get rid of the shackels of fossil-fuel geopolitics to get the same problem with renewables.
Lea: That is true.. I used RERs only as example of how Europe can not be resource independent at the moment 🙂 maybe it is the future in urban mining..
Christophe: Now wind turbines, especially onshore, can be built without rare metals, and a lot of research is done to avoid rare metals in future generation of wind turbines and solar pv
Apart from the many questions, it was fantastic to see people from so many different backgrounds get thinking about the topic. And I think it is exactly this cross-disciplinary collaboration which is needed in the sustainability field at the moment. So thank you everyone for keeping the discussion going, and I have to say you’ve motivated me to try this again another time, for better or worse, so you see you hopefully soon 😉