There is no Silver-Bullet Energy Climate Solution

There is no Silver-Bullet Energy Climate Solution

By: Jeremiah Cutright



If you had to guess which European country has the lowest carbon emissions per capita (say, pre-pandemic levels), who would you pick? Most would probably go for Germany. As the poster child of renewable energy worldwide, this is most definitely the obvious pick. Between 2013 and 2019, Germany's total CO2 emissions declined by an impressive 16%, thanks to a sharp decline in its usage of coal power and a growth in renewables, wind in particular.1 But Germany is not the correct answer. In fact, in terms of per capita CO2 emissions, Germany still remains among the dirtiest of European countries. This is primarily due to its remaining reliance on brown coal (the most polluting type of coal) and the fact that most of the coal that has been displaced has been replaced with natural gas, not renewables. As natural gas has about half the greenhouse gas emissions as coal, there is an apparent relationship here. So if not Germany, then who? This is the part where most people usually start guessing random European countries. Spain? No. The United Kingdom? Nope. The Netherlands? Even dirtier than Germany. Is it a super small country, like Luxembourg, Ireland, or Cyprus? Definitely not, as in 2018, these were respectively the 1st, 3rd, and 5th dirtiest countries in Europe.2 Some reading this article might be expecting the answer to be France due to their heavy reliance on nuclear power, but that isn't correct either (though France is among the cleanest)!

So, what is the answer then, and why? Sweden takes the gold here, and it's for reasons that really shouldn't be that surprising: Sweden has developed a large amount of hydro and nuclear power. These two carbon-free energy sources are the keystone to a modern-day energy transition for the simple reasons that they are not intermittent like solar or wind and tend to be very powerful. Hydro alone provides about half of Sweden's electricity demand, and nuclear meets another third (the rest is met chiefly by wind). In fact, this trend is true for most of the least carbon-polluting countries. Croatia and Latvia each get over 40% of their electricity from hydro, Hungary gets half from nuclear, and Romania gets over half via utilizing both nuclear and hydro.3 France has limited hydropower resources, but nuclear more than compensates, providing 70% of the country's electricity.4 And it's not just Europe: Almost all of South Korea's clean electricity (almost 40% of total generation) comes from nuclear, 67% of the United States' carbon-free electricity comes from nuclear or hydro, and 44% of Brazil's electricity comes from hydropower alone.5-7 To be fair, how electricity is generated is not the only thing that affects a countries carbon emissions. Norway, for example, produces around 90% of its electricity via hydropower, but its CO2 emissions per capita are on par with Germany because of its massive oil industry. Still, the general trend remains.

If you're curious about Germany's progress: after about a decade of aggressive policy and financing, the Germans now produce about 30% of their energy from solar and wind. However, this expansion is expected to cost the country a staggering €500 billion by 2025.8 This is decent progress, but an expansion instead of closure of nuclear plants could have significantly increased the amount of low-carbon energy for a much smaller price tag. Including the existing nuclear and hydropower being utilized in Germany, about 50% of their electricity now comes from low-carbon sources. If nuclear had remained open, today it could be at least 60%, and likely higher than that since non-intermittent sources are critical to the success of intermittent sources like solar and wind. After all, we need power all of the time, not just when the sun is shining. There is also the fact that heavy dependence on wind and solar alone dramatically increases consumer costs of power—as has been seen in Germany and California—and reliance on natural gas, since natural gas is the option used almost exclusively to generate power when these sources are off (like at night for solar) since it can start and stop generation so quickly. In a sort of negative-feedback loop, these rising costs generate public opposition to clean energy, can stall further implementation, and often provide a false illusion of a greener alternative, even though that isn't always necessarily the case.

Sources of energy that are not intermittent are usually either called "load-following" or "baseload" energy. The only difference between these two terms is that load-following simply matches the required demand while baseload sources generally operate at a stable output all of the time, which is essentially the exact opposite of intermittent sources. For now, though, we will lump both of these under the category of "non-intermittent" energy. From what we can tell in our European example, non-intermittent forms of carbon-free energy will be crucial. Of course, we could try to store the energy from intermittent sources, but storage remains extremely expensive and may come with substantial unexpected environmental and technical problems, which I will leave to discuss for another day thoroughly.

The reality is that if we want to decarbonize the energy sector as quickly as possible with as few negative externalities, we need to develop and expand our carbon-free non-intermittent power dramatically while also simultaneously expanding solar and wind. As I have highlighted here, the two traditional and proven methods are nuclear and hydropower. But these each have their own significant drawbacks.

To start, hydroelectric power is reaching its limits. Most of the globe's potential hydroelectric capacity has already been built, and room for expansion is rapidly declining. Add on top of this the concerns that global warming is negatively impacting the productivity of hydroelectric dams (as many rivers are becoming dryer and precipitation less predictable), and attempting to expand this source substantially may turn out to be a dead end. There are also various other concerns with hydropower: It is the one renewable resource that environmentalists tend to not favor, as it can severely disrupt natural ecosystems, and it can be used to deprive people down-river from where the dam is built of water, as has been seen in southern Asia. Small-scale hydropower systems may contribute some, but again they are unlikely to make a significant dent in the energy mix. Potentially the biggest drawback to hydro is that it cannot be utilized in all geographies. A particular type of place is needed to develop hydropower effectively, and there are many countries in the world without access to this.

Despite nuclear power being safe,9 widely available, and having a comparably low environmental impact (including lifetime greenhouse gas emissions lower than hydropower), public opposition remains strong, especially in Germany, Japan, and the US. After the 2011 Fukushima Daiichi nuclear disaster, many countries—especially Germany and Japan—began to phase out their nuclear plants. Because of this, a non-insignificant amount of clean energy was removed from the globe and likely led to the death of thousands via new air pollution since this energy was replaced predominantly by coal and natural gas. While nuclear energy is as safe as solar or wind (when measured as deaths per unit of energy, to compensate for the fact that nuclear provides much more power than either of those), large sections of the public fear it and continue to advocate for its dismantlement. Nobody died from radiation at Fukushima (except for a single clean-up worker), and a Chernobyl scale event is simply impossible today with modern safety systems. The most significant technical drawback to nuclear is that it takes a long time to build a nuclear plant. Many of these sites can take a decade or more to site, plan and construct, and our goal should be to address climate goals as quickly as possible. Nuclear can help significantly, but it cannot handle the problem by itself and may not be able to get over the hurdle of strong public opposition.

There are other options, though. Geothermal, concentrated solar power (commonly referred to as CSP), tidal, and biomass energy are considered possible non-intermittent sources of low-carbon energy.

Geothermal uses heat from underground to generate electricity, has shown to be minimally damaging to the environment, and provides a highly efficient power source. But the availability of geothermal is extremely limited around the world. It has to be developed in places where a lot of heat is close to the surface (think geysers, volcanoes, hot springs, etc.), and there simply aren't that many options for it around. Hypothetically, it could be developed anywhere on the planet if we drill deep enough to get to the heat. However, the technology required to do that economically is likely still a couple of decades away. Geothermal right now can provide substantial power to regions like Indonesia, California, Iceland, and some Sub-Saharan African countries, but widespread adoption outside of these areas is still far away.

CSP is a different twist on solar energy. Instead of capturing energy directly, it uses an array of mirrors to reflect sunlight at a central location, heating what is often a molten salt and using that to generate power through heat. Although the amount of sunlight will vary, these molten salts can stay hot for hours and can therefore act as a type of battery to be tapped into during times of low production, like at night. If done right, CSP can provide power during the day and use the excess heat in its molten salt batteries to steadily provide power during the night. CSP still has several hurdles of its own, however. It remains costly, and it will only work in places that get substantial sunlight, such as the southwest United States, Africa, or the Middle East. The other problem that CSP runs into is that it's only, let's say, "half" non-intermittent. CSP may provide a consistent level of energy among fluctuating weather, but this can be disrupted by several bad days. One cloudy day and a CSP system are likely to be okay. But have a cloudy week, and CSP will fail to provide the needed energy. This is a technical and practical barrier that will probably never be solved.

Tidal is still very much experimental. Tidal energy essentially uses the forces of waves in the ocean to generate power. Obviously, this means that yet again, tidal is a form of energy that is only available in some places on the planet, but as most of the world's energy is needed on coastlines, this isn't such a big problem. There isn't much data yet on tidal energy, so I won't speculate too much about its helpfulness, but hopefully, there will be promising developments soon.

Our last option is biomass, basically the burning of trees and other organic compounds for energy. Although this is probably the single oldest form of energy that humans have ever used, and it is usable just about anywhere on the planet (except for arid regions), it has significant drawbacks. Namely, biomass isn't actually carbon-free. In fact, the best biomass projects examined still produce twenty times as much greenhouse gas emissions as wind power! This is to say nothing about the land use, air pollution, and water consumption issues that biomass deals with. Innovations are looking at solving this problem by growing suitable plants, but doubts among many are high.

What can we say for sure at this moment? There is no silver-bullet solution. The closest are nuclear, hydro, and geothermal (if the technology can mature quickly enough), but they each have their own significant drawbacks. We will need all of these options to reduce our carbon emissions successfully. We can use hydro in Asia, Europe, and the Americas. Geothermal around the Pacific Ocean (the "Ring of Fire" region) and Africa. CSP can shine in Africa, the Middle East, and Australia. Tidal may be able to alleviate the pain felt on most coastlines. And if biomass can be done more effectively, it will be highly applicable in North America, Europe, and Asia. We will need a non-insignificant amount of nuclear power to fill in the gaps. Still, traditional intermittent wind and solar sources will also help substantially, especially if backed up by batteries or if the power can be transmitted long distances. Nuclear, CSP, and geothermal also come with the added benefits that they can provide heat for industrial processes (such as making steel or cement) and electricity. This is a crucially important point because electricity is just one part of the bigger picture of "energy," including things like oil, gasoline, heating, and others. We predominantly use coal to generate the required heat for making steel, cement, and other products because it is the cheapest option. But if we want a low-carbon world, we need to find cleaner sources to provide this heat (after all, it's not like we can just stop making steel). We need all of these solutions, not just one or two. To rely just on wind and solar without developing non-intermittent low carbon forms of energy would be highly irresponsible of us not just to ourselves, but also to future generations.



Citations

“Germany - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/germany.


“EU: GHG Emissions Per Capita.” Statista, 4 Aug. 2021, https://www.statista.com/statistics/986392/co2-emissions-per-cap-by-country-eu/.


IEA/countries


“France - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/france.


“Korea - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/korea.


“United States - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/united-states.


“Brazil - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/korea.


“Germany - Countries & Regions.” International Energy Agency (IEA), https://www.iea.org/countries/germany.


Ritchie, Hannah, and Max Roser. “Nuclear Energy.” Our World in Data, 28 Nov. 2020, https://ourworldindata.org/nuclear-energy#citation.



Image credit: “Per Capita Co₂ Emissions.” Our World in Data, https://ourworldindata.org/grapher/co-emissions-per-capita?region=Europe.