Measurement and Climate Change – Part 1

Measurements used in the science of energy.

In the last series of essays, we explored how measurement can be used to mislead, and how governments that used measurement to mislead spurred some historic revolutions.  In this series of essays, we’ll explore popular media and government measurement (or mismeasurement, or non-measurement) of “climate change,” their proposed solutions to increased carbon emissions, and the overall effects of such solutions compared to the problem.

As we start this series on measurement in climate change, it’s important to set out the science of energy, to get a better understanding of the comparative efficiency of different energy sources, and therefore their comparative benefits to humankind in their ability to provide energy.

Vaclav Smil, in his book How the World Really Works: The Science Behind How We Got Here and Where We're Going, provides an excellent discussion of this topic.  He writes:

The first law of thermodynamics states that no energy is ever lost during conversions: be that chemical to chemical when digesting food; chemical to mechanical when moving muscles; chemical to thermal when burning natural gas; thermal to mechanical when rotating a turbine; mechanical to electrical in a generator; or electrical to electromagnetic as light illuminates the page you are reading. However, all energy conversions eventually result in dissipated low-temperature heat: no energy has been lost, but its utility, its ability to perform useful work, is gone (the second law of thermodynamics) … There are many choices available when it comes to energy conversions, some far better than others. The high densities of chemical energy in kerosene and diesel fuel are great for intercontinental flying and shipping, but if you want your submarine to stay submerged while crossing the Pacific Ocean then the best choice is to fission enriched uranium in a small reactor in order to produce electricity. And back on land, large nuclear reactors are the most reliable producers of electricity: some of them now generate it 90–95 percent of the time, compared to about 45 percent for the best offshore wind turbines and 25 percent for photovoltaic cells in even the sunniest of climates—while Germany’s solar panels produce electricity only about 12 percent of the time. This is simple physics or electrical engineering, but it is remarkable how often these realities are ignored. Another common mistake is to confuse energy with power, and this is done even more frequently. It betrays an ignorance of basic physics, and one that, regrettably, is not limited to lay usage. Energy is a scalar, which in physics is a quantity described only by its magnitude; volume, mass, density, time, and speed are other ubiquitous scalars. Power measures energy per unit of time and hence it is a rate (in physics, a rate measures change, commonly per time). Establishments that generate electricity are commonly called power plants—but power is simply the rate of energy production or energy use. Power equals energy divided by time: in scientific units, it is watts = joules/seconds. Energy equals power multiplied by time: joules = watts × seconds. If you light a small votive candle in a Roman church, it might burn for 15 hours, converting the chemical energy of wax to heat (thermal energy) and light (electromagnetic energy) with an average power of nearly 40 watts … Most recently, a poor understanding of energy has the proponents of a new green world naively calling for a near-instant shift from abominable, polluting, and finite fossil fuels to superior, green and ever-renewable solar electricity. But liquid hydrocarbons refined from crude oil (gasoline, aviation kerosene, diesel fuel, residual heavy oil) have the highest energy densities of all commonly available fuels, and hence they are eminently suitable for energizing all modes of transportation. Here is a density ladder (all rates in gigajoules per ton): air-dried wood, 16; bituminous coal (depending on quality), 24–30; kerosene and diesel fuels, about 46. In volume terms (all rates in gigajoules per cubic meter), energy densities are only about 10 for wood, 26 for good coal, 38 for kerosene. Natural gas (methane) contains only 35 MJ/m3—or less than 1/1,000 of kerosene’s density.[36] The implications of energy density—as well as of fuel’s physical properties—for transport are obvious. Ocean liners powered by steam engines did not burn wood because, everything else being equal, firewood would have taken up 2.5 times the volume of the good bituminous coal required for a transatlantic crossing (and be at least 50 percent heavier), greatly reducing the ship’s capacity to transport people and goods. There could be no natural gas–powered flight, as the energy density of methane is three orders of magnitude lower than that of aviation kerosene, and also no coal-powered flight—the density difference is not that large, but coal would not flow from wing tanks to engines.

Beyond energy density, one needs to consider other factors, like ease of production and portability:

[T]he advantages of liquid fuels go far beyond high energy density. Unlike coal, crude oil is much easier to produce (no need to send miners underground or scar landscapes with large open pits), store (in tanks or underground—because of oil’s much higher energy density, any enclosed space can typically store 75 percent more energy as a liquid fuel than as coal), and distribute (intercontinentally by tankers and by pipelines, the safest mode of long-distance mass transfer), and hence it is readily available on demand. Crude oil needs refining to separate the complex mixture of hydrocarbons into specific fuels—gasoline being the lightest; residual fuel oil the heaviest—but this process yields more valuable fuels for specific uses, and it also produces indispensable non-fuel products such as lubricants. Lubricants are needed to minimize friction in everything from the massive turbofan engines in wide-body jetliners to miniature bearings. Globally, the automotive sector, now with more than 1.4 billion vehicles on the road, is the largest consumer, followed by use in industry—with the largest markets being textiles, energy, chemicals, and food processing—and in ocean-going vessels. Annual use of these compounds now surpasses 120 megatons (for comparison, global output of all edible oils, from olive to soybean, is now about 200 megatons a year), and because the available alternatives—synthetic lubricants made from simpler, but still often oil-based, compounds rather than those derived directly from crude oil—are more expensive, this demand will grow further as these industries expand around the world.  Another product derived from crude oil is asphalt. Global output of this black and sticky material is now on the order of 100 megatons, with 85 percent of it going to paving (hot and warm asphalt mixes) and most of the rest to roofing. And hydrocarbons have yet another indispensable non-fuel use: as feedstocks for many different chemical syntheses (dominated by ethane, propane, and butane from natural gas liquids) producing a variety of synthetic fibers, resins, adhesives, dyes, paints and coatings, detergents, and pesticides, all vital in myriad ways to our modern world. Given these advantages and benefits, it was predictable—indeed unavoidable—that our dependence on crude oil would grow once the product became more affordable and once it could be reliably delivered on a global scale.

Regarding energy like wind and solar:

In large, populous nations, the complete reliance on these renewables would require what we are still missing: either mass-scale, long-term (days to weeks) electricity storage that would back up intermittent electricity generation, or extensive grids of high-voltage lines to transmit electricity across time zones and from sunny and windy regions to major urban and industrial concentrations … Could these new renewables produce enough electricity to replace not only today’s generation fueled by coal and natural gas, but also all the energy now supplied by liquid fuels to vehicles, ships, and planes by way of a complete electrification of transport? And could they really do so, as some plans now promise, in a matter of just two or three decades? [E]ven in this era of high-tech electronic miracles, it is still impossible to store electricity affordably in quantities sufficient to meet the demand of a medium-sized city (500,000 people) for only a week or two, or to supply a megacity (more than 10 million people) for just half a day … It is impossible to decide which class of electricity converters has had a greater impact—lights or motors. The conversion of electricity into kinetic energy by electric motors first revolutionized nearly every sector of industrial production and later penetrated every household niche … The service sector now dominates all modern economies, and its operation is completely dependent on electricity. Electric motors power elevators and escalators, air-condition buildings, open doors, and compact garbage. They are also indispensable for e-commerce, as they power mazes of conveyor belts in giant warehouses. But the most ubiquitous units are never seen by people who rely on them every day. They are the tiny units activating mobile phone vibrators: the smallest ones measure less than 4 mm × 3 mm, their width being less than half the width of an average adult’s pinky nail. You can see one only by dismantling your phone, or watching a video of that operation online … Without electricity, drinking water in all cities—as well as liquid and gaseous fossil fuels everywhere—would be unavailable. Powerful electric pumps feed water into the municipal supply, and they have an especially demanding task in cities with high commercial and residential densities where water must be lifted to a great height. Electric motors run all the fuel pumps needed to move gasoline, kerosene, and diesel into tanks and wings. And while there may be plenty of natural gas in distribution gas pipelines—gas turbines are often used to move the fuel—in North America, where forced-air heating dominates, small electric motors operate fans that push the air heated by natural gas through the ducts.

Not surprisingly, electricity has been in particularly high demand worldwide:

[D]emand for electricity has been growing much faster than the demand for all other commercial energy: in the 50 years between 1970 and 2020, global electricity generation quintupled while the total primary energy demand only tripled. And the growth of baseload generation—the minimum amount of electricity that has to be supplied on a daily, monthly, or annual basis—was further increased as progressively larger shares of populations moved to cities … If the COVID-19 pandemic brought disruption, anguish, and unavoidable deaths, those effects would be minor compared to having just a few days of a severely reduced electricity supply in any densely populated region, and if prolonged for weeks nationwide it would be a catastrophic event with unprecedented consequences. There is no shortage of fossil fuel resources in the Earth’s crust, no danger of imminently running out of coal and hydrocarbons: at the 2020 level of production, coal reserves would last for about 120 years, oil and gas reserves for about 50 years, and continued exploration would transfer more of them from the resource to the reserve (technically and economically viable) category.

For decades to come, fossil fuels will remain the most reliable source of energy for a large variety of uses:

Intermittency of wind and solar electricity poses no problems as long as these new renewables supply relatively small shares of the total demand, or as long as any shortfalls can be made up by imports … In 2020, two decades after the beginning of Energiewende, its deliberately accelerated energy transition, Germany still had to keep most of its fossil-fired capacity (89 percent of it, actually) in order to meet demand on cloudy and calm days. After all, in gloomy Germany, photovoltaic generation works on average only 11–12 percent of time, and the combustion of fossil fuels still produced nearly half (48 percent) of all electricity in 2020 … And in the US, where much larger transmission projects would be needed to move wind electricity from the Great Plains and solar electricity from the Southwest to high-demand coastal areas, hardly any long-standing plans to build these links have been realized … How soon will we fly intercontinentally on a wide-body jet powered by batteries? News headlines assure us that the future of flight is electric—touchingly ignoring the huge gap between the energy density of kerosene burned by turbofans and today’s best lithium-ion (Li-ion) batteries that would be on board these hypothetically electric planes. Turbofan engines powering jetliners burn fuel whose energy density is 46 megajoules per kilogram (that’s nearly 12,000 watt-hours per kilogram), converting chemical to thermal and kinetic energy—while today’s best Li-ion batteries supply less than 300 Wh/kg, more than a 40-fold difference. Admittedly, electric motors are roughly twice as efficient energy converters as gas turbines, and hence the effective density gap is “only” about 20-fold. But during the past 30 years the maximum energy density of batteries has roughly tripled, and even if we were to triple that again densities would still be well below 3,000 Wh/kg in 2050—falling far short of taking a wide-body plane from New York to Tokyo or from Paris to Singapore, something we have been doing daily for decades with kerosene-fueled Boeings and Airbuses.

In the next essay in this series, we’ll look at what’s left out of popular climate models.