The real currency of our global economy is energy — not the US Dollar or Gold. We often attribute achievements of the past century to man’s ingenuity but how far would we have got without energy? The chart below shows the growth in global energy consumption over two centuries. Imagine what would happen if we had to revert back to energy usage levels from 1900 — about 6% of current consumption. The lights of the global economy would quite literally go out.
Unfortunately our reliance on carbon-based fuels has caused global CO2 emissions to soar, with disastrous consequences for the planet.
At the Glasgow Climate Change Conference, almost 200 countries agreed to:
- “reduce the gap between existing emission reduction plans and what is required to reduce emissions, so that the rise in the global average temperature can be limited to 1.5 degrees”; and
- called on nations “to phase down unabated coal power and inefficient subsidies for fossil fuels.” (COP26)
Net zero by 2050
The Net Zero by 2050 report from the International Energy Agency (IEA) notes that COP26 signatories are likely to miss their target:
The number of countries that have pledged to achieve net‐zero emissions has grown rapidly over the last year and now covers around 70% of global emissions of CO2. This is a huge step forward. However, most pledges are not yet underpinned by near‐term policies and measures. Moreover, even if successfully fulfilled, the pledges to date would still leave around 22 billion tonnes of CO2 emissions worldwide in 2050. The continuation of that trend would be consistent with a temperature rise in 2100 of around 2.1 °C.
Energy sources
The chart below, showing global energy use by source, reflects the scale of the problem. Note that the 2020 fall in global emissions was due to the COVI-19 pandemic and is “already rebounding strongly as economies recover” (IEA report). Global consumption of oil and gas has continued to grow despite the introduction of wind and solar. Coal consumption declined since 2014 but was partly replaced by an increase in the rate of gas consumption in 2018-2019. That trend is likely to continue — as gas produces roughly half the CO2 emissions of coal — and has resulted in a sharp spike in global gas prices.
Wind and solar
It is unlikely that solar and wind — with 2020 outputs of 900 TWh and 1,600 TWh respectively — will ever be able to replace the combined 125,000 TWh of energy generated by coal, oil and gas.
Hydro-electric
Hydropower growth is expected to slow. Having enjoyed a surge in the past 20 years, with heavy dam construction in China, new opportunities are mostly limited to Africa and South America.
Electric vehicles
Electric vehicles are expected to dent global oil demand over time but oil producers are not having sleepless nights. Bloomberg New Energy research estimates that electric and fuel cell vehicles will displace 21 million barrels per day in oil demand by 2050. Current oil usage is 102 mb/d (IEA 2021) but is increasing at annual rate of 1 mb/d (IEA), leaving us with an estimated net increase in oil consumption of 8 mb/d by 2050.
Hydrogen
Hydrogen is being touted as an alternative to oil and gas but there are two hurdles to overcome. First is the cost of generating hydrogen. There are two alternatives: creating hydrogen from water using electrolysis and separating hydrogen from methane gas (CH4) using a catalyst. Electrolysis has the advantage of a cheaper feedstock (water) but the most efficient PEM electrolyzers require expensive platinum and iridium-coated cathodes and anodes, respectively, for operation at high temperatures. Methane pyrolysis requires natural gas as a feedstock but has the advantage of generating saleable carbon as a by-product. Carbon black is used in manufacturing car tires and industrial rubber, but most feasibilities I have seen assume current prices which are based on a limited supply. Separating methane would generate 2 tons of carbon for every ton of hydrogen, creating an over-supply.
The downfall of both alternatives is that they require vast amounts of energy for the conversion. That brings us back to the question: where are we going to find cheap CO2-free sources of energy on a vast scale?
The second major hurdle for hydrogen is the cost of manufacturing fuel cells. These also require cathodes and anodes coated with platinum group metals to prevent erosion at high temperatures.
Hydrogen generation is not yet economically viable and hopes for future cost reduction are based on as yet undeveloped technology.
The dark side of solar
Significant achievements have been made in reducing the cost of solar panels — but at a cost.
Xinjiang has become a major polysilicon production hub in China, as the industry requires extensive amounts of energy, and that makes relatively cheaper electricity and abundant thermal power in Xinjiang appealing. (Global Times)
Xinjiang has also been the focus of reports on the use of Uighur forced labor. Savings achieved through cheap coal-fired power and slave labor are not real savings but come at major costs in terms of CO2 emissions and human suffering.
Nuclear
The only viable alternative to carbon fuels, especially coal, is nuclear. Initial construction costs may appear high but most estimates are based on the few large-scale nuclear power stations built as stand-alone projects over the past four decades. Significant savings are achievable by building small modular reactors (SMRs) in a factory setting, with robotic welders, and transporting them to site. Economies of scale would play a huge part in achieving affordable CO2-free nuclear energy around the globe.
Nuclear energy is far safer than carbon fuel alternatives and comparable to renewable energy. Especially when one considers that the safety record below is based on old, inefficient designs — Chernobyl and Fukushima — that are far more prone to accidents than modern SMRs.
Nuclear delivers the highest return when measured in terms of Energy Returned on Energy Invested (EROEI or EROI)1. EROI is the ratio of energy returned to energy invested in an energy source along its entire life-cycle2.
Energy Returned on Investment, or EROI, with and without energy storage (buffering or load following). CCGT is combined-cycle natural gas turbine. Nuclear is conventional Pressurized Water Reactors; fast reactors are several times higher. Solar CSP is concentrated solar (á la Ivanpah), solar PV is photovoltaic solar cells like on rooftop solar. Energy sources must exceed the economic threshold of about 7 (blue line) in order to yield the surplus energy required to support a modern society. After Weißbach (2013)
There are certainly political obstacles for the nuclear industry to overcome — not least its poor public image — but we can already see progress being made in Europe and North America in terms of classifying nuclear as “green” energy.
Notes
- EROI (or EROEI) = Quantity of Energy Supplied ÷ Quantity of Energy Used in the Supply Process
- James Conca: EROI – A Tool To Predict The Best Energy Mix, Forbes (2015)