Abundant energy helps feed us all
It takes 7 Calories of energy to produce 1 Calorie to eat
What do a gallon of gasoline and a gallon of milk have in common? They are both sources of energy – gasoline for your car, milk for your body. What’s more, energy is required to produce, preserve, and deliver them both to you. Without access to that energy, the food system as we know it could not exist.
How much energy are we talking about? Daphne Norton of Emory University notes that, on average, it takes at least 7 Calories of energy to produce 1 Calorie of food. For an average American, that means it takes about 60% as much energy to put food on your table as you put into your car each year.1 At first glance, that seems crazy - how can food require so much energy? But to deliver the energy on your plate, it takes sunlight and fertilizer to help plants grow, fuel to move tractors across fields and trucks to stores, and electricity to power your refrigerator.
Every one of those steps requires energy, and without them, the food system as you know it could not exist. As we will see, cheap, abundant energy unlocks human flourishing by delivering affordable food.
Sunlight is our food’s first energy source and it is free, abundant, and (mostly) reliable. Plants require sunlight to grow as sunlight is critical to photosynthesis, a plant’s metabolic process. Lack of sunlight creates problems for plant growth. In 1815, the Indonesian volcano Mount Tambora erupted, launching particulate matter into the atmosphere. This particulate matter was so dense, it blocked out sunlight the next summer and made the temperature cooler, so much so that crops failed in Europe and the US.
Outside of the sun, most of the remaining energy to produce and deliver the food you eat must be contributed by man-made energy sources. The USDA provides a more detailed breakdown of energy use by source and use for the US food system. The USDA’s analysis reveals the categories of energy, such as transportation, food production, and home preparation, required for feeding all of us. The bar chart shows the proportions of these different factors. In total, the food system required 11.9 quadrillion British thermal units (qBtus) in 2012 to feed Americans. The largest single categories are household food service (making the food yourself) and food processing before it gets to the stores and restaurants where consumers buy it.
Food is of no use until it reaches your table, and it takes energy to transport it there. Fertilizers are produced around the world and must be shipped to the farm, where tractors require fuel to move across the fields. Crops are transported from the farm to mills and feedlots, or shipped across the oceans to other countries. From the packaging plant, foods move to the grocery store where you buy them and drive them home. All in, the USDA estimates that a little over 10% of the total energy consumption in the food system is for transportation. Said differently, the average American vehicle could drive from New York City to St. Louis with the energy it takes to transport one person’s food to your house.
Before the crop can ever be shipped to market, energy is required to produce it. This includes energy used on the farm and ranch, but also energy consumed in the production of fertilizers, crop chemicals, and equipment. To look at one example, the US consumes roughly 12 million metric tons of nitrogen fertilizer annually. Producing 1 ton of nitrogen (in the form of ammonia) requires almost enough natural gas to heat the average US house for 1 year. Just making nitrogen fertilizers requires enough energy to heat more housing units than there are in the state of New York. However, the impact of those fertilizers has been no less than world-changing - some have estimated that almost half of the global population alive today is able to eat due to the additional productivity that synthetic fertilizers have enabled.
As food moves closer to the end consumer, electricity becomes more important. Some of the electricity is used in food processing, but a large portion of the downstream use is for home appliances such as refrigerators and ovens to preserve and prepare food. The USDA estimates almost 30% of the total energy consumption in the US food system is for household foodservice. The majority of that energy consumption at home is in the form of electricity, with natural gas also playing a role. The payoff for this large energy consumption is significant. Without refrigeration, perishable foods would spoil at a much higher rate. The alternative to electric or gas cooking is often coal, wood, or dung - a reality for many parts of the world.
All the energy consumed in the food value chain comes at a cost, and instability or scarcity can dramatically change that cost. In 2022, the Dutch bank ING estimated that European food producers saw the energy cost component of their costs increase up to five times. As illustrated in the chart below, food prices track changes in energy prices. The strong relationship between food and energy prices tells us that periods of cheaper energy may correspond to more affordable food prices.
Providing more affordable food is important worldwide, but particularly in the developing world, where large portions of the population cannot afford to purchase food that meets dietary guidelines. As the map from Our World in Data shows below, for parts of Sub-Saharan Africa, South Asia, and Southeast Asia, affording a healthy diet remains beyond reach of a majority of citizens. The USDA has also looked at how food expenditures as a portion of budget vary depending on the income level of countries. Lower income countries often spend a much higher proportion of their income on food, which limits the ability of their citizens to spend money as they see fit. Cheap, abundant energy can make a difference in improving the quality of life for many if it makes food more affordable.
So, what are the takeaways from all this? It takes a tremendous amount of energy to help us grow, transport, preserve, and prepare the food we eat. Over time, the form of that energy may change due to innovation, but we cannot lose sight of the benefits of affordable energy on the food system. Every dollar not spent on food is a dollar that can be spent on housing, education, repairs, or…anything. There is a significant opportunity to better the lives of many around the world by pursuing policies that enable abundance, both of energy and of food.
How do we get to 60%? By following the conversion steps below:
The USDA reports that per capita Calorie availability in the U.S. is 3,864 Calories per day, which means it takes roughly 27,000 Calories of energy to produce an American’s daily available food (7 Calories required x 3,864 Calories per capita) or almost 10 million Calories per year (27,000 Calories x 365 days).
10 million Calories per year, multiplied by 0.004184 Megajoules (MJ) of energy per Calorie (Kilocalorie, to be precise) equals ~42,000 MJ per year.
A gallon of Gasoline has ~121 MJ, which means the energy in food is equivalent to 42,000 MJ / 121 MJ per gallon or ~350 gallons of gasoline per year.
According to the US Department of Transportation, the average miles driven by all Americans is 13,476, and the average fuel efficiency of light duty vehicles per the Bureau of Transportation Statistics is 22.8 miles per gallon. Divide the mileage by the fuel efficiency, and you get ~590 gallons consumed per driver per year.
350 gallons of energy in food / 590 gallons per year = 59%.
This calculation does not include energy provided by the sun, which means it takes more than 7 Calories of energy to produce 1 Calorie of food.
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