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How would a world look like that runs 100% on renewable energy with only current technology?

We are living in a world where everyone came together to build that future that does not rely on fossil fuels and nuclear for energy production. Lets put aside politics and economy and focus on the technology:

How would the landscape change? How would you be able to deal with both the lows and the peaks of production? Is that possible with current technology and resources? If not, what kind of scientific, technological advancements would be necessary?

There are some places that run 100% on renewables. But most of them either rely heavily on hydro, or import/export with regions that use fossil fuels. Not every place in the world has the capacity to ramp up hydropower that much and the second option obviously does not work any more.


edit: no, nuclear is not renewable, because you burn stuff inside, that does not regrow somewhere. Fusion energy is off limits for this questions because of the restriction to current technology

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    $\begingroup$ Reminder to close-voters: The problem cannot be fixed if the OP is not made aware of it. $\endgroup$
    – Frostfyre
    Nov 12, 2019 at 17:12
  • $\begingroup$ That being said: I agree with the too broad close votes. Asking how the entire world would change based on a revolutionary concept is far too much for our Q&A format. $\endgroup$
    – Frostfyre
    Nov 12, 2019 at 17:15
  • $\begingroup$ You need to build a global 1 MV DC electrical grid. The rest is simple. $\endgroup$
    – Karl
    Nov 12, 2019 at 19:41
  • $\begingroup$ Solar and wind are not renewable resources. When the sun dies, no more of these power sources. The question should not be about renewable, the question should be viable power source for X years, where X is enough to make you happy with the solution. $\endgroup$ Nov 12, 2019 at 20:40

6 Answers 6

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Is that possible with current technology and resources?

No. With current technology this is not possible. Some places don't have flowing water (no hydro), or enough sunlight (which is everywhere during night, or places with lots of clouds), or enough wind, and so on. One of the biggest issues with renewable energy sources is storing the energy during off-peak hours. When the sun goes down your solar panels do nothing. This requires: batteries. But there's a problem: batteries are not exactly green-friendly. There's dangerous chemicals, manufacturing hazards, and not to mention when the battery reaches it's lifespan the disposal and recycling of them is complex and has it's own issues.

If not, what kind of scientific, technological advancements would be necessary?

Nuclear fusion is the "holy grail" of energy generation. There is always some type of excitement around getting fusion in our lifetimes. Whether or not this will happen, only time will tell.

Right now, nuclear power plants are nuclear fission power plants - usually splitting uranium (and thorium is becoming more popular). But nuclear fusion is using hydrogen, and it's byproduct is water. We will never run out of hydrogen, and pure H2O water as a byproduct is nothing requiring concern. Furthermore, fusion can generate a lot more energy, and faster, than fission. It's safe, stable, and 100% renewable.

Once nuclear fusion becomes a reality, the only hindrance is building the reactors. This would require some up-front money from the federal governments, as most cities, states, and/or small countries would not be able to afford it on their own. These reactors would be dropped into city grids as they currently are. Maintaining them could easily cost the same or less of current fossil-fuel plants.

After fusion replaces city grids, the only remaining barrier would be oil and gas for production in rural areas, which could be switched to solar/hydro/wind depending on location. Areas near to cities could be connected to the city's grid for less money than converting everyone to solar, so the only real issue is those "really out there".

Even then, there might be some locations near the poles (north greenland, antartica, way north in Alaska, etc) who are too cold and deal with multiple days without sunlight or wind. These locations might still need to use fossil fuels, but you're talking less than 0.01% of the world's population, so the end effect is negligible.

Assuming nuclear fusion exists, I think this would be the most likely possibility available.

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  • $\begingroup$ Almost. Some place don't have enough solar/wind/hydro to do this "reasonably". Spend enough money and anywhere can be made 100% renewable. $\endgroup$ Nov 12, 2019 at 15:51
  • $\begingroup$ Nuclear fusion is sci-fi tech in my opinion and that clashes with my idea of current technology. Also, there are other possibilities to store energy than batteries, e.g. pump storage. I'd wager that Alaska might have it significantly easier to go full renewable because of possibilities for hydro, much more so as e.g. France $\endgroup$
    – don-joe
    Nov 12, 2019 at 15:59
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    $\begingroup$ @don-joe: Nuclear fusion may clash with your idea of current technology, but ITER, the International Thermonuclear Experimental Reactor, is under construction (actually in the assembly phase) and is projected to begin operating in 2025... $\endgroup$
    – AlexP
    Nov 12, 2019 at 16:20
  • $\begingroup$ @don-joe What Alex said, but also I have an incredibly difficult time believing hydro would work in far north Alaska, like Utqiagvik $\endgroup$
    – cegfault
    Nov 12, 2019 at 17:11
  • $\begingroup$ Norway and British Columbia are both in the Wikipedia list I posted with more than 95% hydro energy, so being far north is not really a problem. $\endgroup$
    – don-joe
    Nov 12, 2019 at 17:14
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I suspect that you would use a wide range of sustainable energy sources, ranging from wind and solar to wave energy, tidal energy, geothermal energy, and biofuel (first and second generation). This variety will reduce the overall lows and peaks in production.

You would probably see a lot of wind farms (many offshore) and solar farms, but also a lot of solar panels and wind turbines on roofs, as well as local biogas plants where organic waste is turned into energy. Many houses will be more-or-less self-suffient in energy, but may buy and sell energy on the smart grid; e.g. houses with solar cells will sell power on sunny days, but buy on cloudy, windy days.

Transport may be the biggest issue due to energy density, but we are seeing innovation where carbon oxide is combined with hydrogen to make formic acid, which is a very compact fuel for fuel cells, as well as biofuel for airplanes.

Storing energy can be done by using excess power to split hydrogen from water and storing it as formic acid, as described before, though there is some energy loss. Batteries may also store electric energy for weeks or even months without overmuch loss. Yopu can also use excess energy to pump water up a tower or hill and then use it to create energy later with turbines.

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The game with renewable energy is that it's always windy somewhere, the sun is always shining somewhere, somewhere always has geothermal, somewhere always has waves, somewhere always has water in their dam. The larger your power distribution network, the more stable the supply and the more stable the load.

It's not about localising, it's about spreading your power sources as widely as possible so you're not dependent on local conditions in any one place or on any one source of power. It works better for places that have hydro or geothermal as they're less sensitive to minor variation, but large scale hydro power is not entirely environmentally friendly in its own right.

In turn this large power network spreads the load, if you're covering three time zones then rather than having a large spike as everyone in one region gets home and puts the TV on, that spike is spread over several hours.

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  • $\begingroup$ that would require a massive grid, stretching no less than 6,000 miles in any direction, causing the vast majority of electric power to be lost during transmission. $\endgroup$
    – user20762
    Nov 12, 2019 at 17:20
  • $\begingroup$ Also, such massive networks would require standardization, and political cooperation that I don't think could be acheived $\endgroup$
    – user20762
    Nov 12, 2019 at 17:35
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    $\begingroup$ @RichardU It isn't so much the distance required that I would be concerned about, it is the capacity. Transmission lines capable of helping balance loads across regions is easy - we do that reasonably well already - but capacity to actually power entire regions from across a continent? That is a truly absurd scale coming with an absurd cost, especially with the issue that they will sit mostly unused most of the time. $\endgroup$ Nov 12, 2019 at 18:27
  • $\begingroup$ @pluckedkiwi yes, that and all the power that would be lost due to leakage and resistance. $\endgroup$
    – user20762
    Nov 12, 2019 at 18:44
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It's simply a matter of priorities. Let's focus on the United states because we have good studies for this area. An analysis by the energy research firm Wood Mackenzie, finds that that shifting to 100% renewable over the decade would cast 4.5 trillion. The US federal budget is $1.2 trillion for discretionary spending (per year) so this number is doable (if expensive). Ultimately, it would come down to sacrificing other budget priorities to make it happen (which seems unlikely in the current political climate).

To achieve that, the US would have to massive increase the amount of wind and solar capacity as well as investing in 900 gigawatts of battery storage. Technological innovation could bring this cost down, but ultimately there is a limit to the efficiency of technologies like Solar and Battery Storage. The majority of solar panels range from 15% to 17% efficiency currently (and only work while the sun is shining), while battery storage requires massive amounts of lithium mining which brings its own environmental issues.

Ultimately, it may be much cheaper in the long run to skip this massive 4.5 trillion rollout and instead focus on the next great tech: Fusion Power. Unlike Solar and Wind, Fusion power would provide a steady base of power without the toxic nuclear waste issue of Fission power, or the variability in output of current renewables that causes the "duck curve" imbalance between renewable energy production vs demand.

There's a running joke that Nuclear Fusion is always "30 years away", but this isn't a fault in the technology: It's a matter of scale. To achieve net energy output greater than input (called the Q factor), you need a truly massive reactor that can achieve plasma temperatures in the hundreds of million of degrees. This is actually far hotter than the Sun at only 27 million degrees, because the Sun is surprisingly inefficient. At 27 million degrees, the Sun produces about the same energy per unit volume as a backyard compost pile. It's only the massive size of the Sun that makes its energy production noteworthy. On Earth we have to do better.

The current timeline has us building the ITER fusion reactor (with a momentary Q factor of 10), by 2035 and then building an even larger reactor called DEMO with a Q factor of 25 which will finally utility scale power of 2 gigawatts by 2048. Only after the successful demonstration of DEMO will fusion power start to be commercially viable.

enter image description here

Source: https://link.springer.com/article/10.1007/s13280-015-0732-y

If that seems like a long time to you, I agree. The reason nuclear fusion research has taken so long is that we are only investing less than a billion dollars a year into the technology, compared to Solar and Wind which get hundreds of billions per year. Considering the upside of truly unlimited steady power, that seems a bit absurd, but Governments only feel comfortable spending money on proven technologies. If a similar investment was made into Nuclear Fusion, the technology could be here far far sooner.

enter image description here

Source: https://commons.wikimedia.org/wiki/File:U.S._historical_fusion_budget_vs._1976_ERDA_plan.png

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  • $\begingroup$ I liked the study, but I strongly disagree with the fusion energy hype. The very important difference to e.g. solar or wind is, that for those we can have incremental improvement. There is a proof of concept, we know it works, its just a question of making it better and more reliable. You simply cannot anticipate technological advancements. See computing power and all that. Nuclear fusion would magically solve problems, that are relevant right now, that I want to see solved with non-magical means. $\endgroup$
    – don-joe
    Nov 12, 2019 at 17:05
  • $\begingroup$ And yes, I am also very excited about ITER. It is super cool! But it is just not the direction of my question. $\endgroup$
    – don-joe
    Nov 12, 2019 at 17:06
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I'm assuming Nuclear is "Non-Renewable"

The world would probably look a lot more localized, at least from a power generation point of view.

Most renewables have a lower energy density to non-renewables. So without the existing national grid, why would you create it? It would be as efficient to have each local district (or even house) have their own generation system. The main issue I can see is in the event of a long lasting non-typical event (cloudy, winds too strong to use etc), you may end up running out of stored power (I seem to remember this was an issue in Star Trek 4 at the beginning of the film).

The air will be somewhat cleaner without coal-fired power stations, but probably not noticeably so, unless you've not got diesel/petrol(gasoline) powered systems too.

One question - many large "diesel" powered vehicles (trains anyway), actually have diesel generators and use electric engines - would this be the case in your renewable world?

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It's possible, but very, VERY costly, and not environmentally friendly at all.

Because of the inconsistencies of solar and wind, massive batteries would need to be built to accommodate conditions such as still air, and night. Lithium is extracted through pit mining, like copper, so massive mines, and environmental damage.

additionally, a very sophisticated system in the electric grid would be required to deal with surges and dropoffs due to varying cloud and wind activities. There would also need to be a massive coordination of mining efforts to dig up more permanent magnets for the wind turbines, and silicon for the solar panels to the point where computers would need to use Germanium for their chips instead of silicon.

More land would need to be cleared to allow for the production of bio fuels, so we'd have more deforestation, and the price of food would go up significantly. Wood burning power plants would take the place of coal plants, so more land would need to be taken to set aside for the growing of fuel.

Algae tanks could be setup offshore to provide the raw materials for bio diesel, but again, it would be expensive.

Then, of course there's the problem of transporting all of these fuels. Right now, a typical crossing of the Atlantic uses $2,000,000 worth of fossil fuels. That cost would likely quadruple the costs, so imports and exports would be more expensive, causing more local production.

So, is it possible, yes, but it would be dirty, expensive, and lower the standard of living worldwide to barely above subsistence levels.

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