Energy: A Crash Course. Generation and Consumption.
Energy is the ability to do work. Fossil fuels are the “densest” energy form available, but they come at the high cost of all life on Earth. We have the opportunity to decarbonize our electrical grid. We have the obligation to future generations that we accomplish this quickly.
Welcome back, readers! It’s time for a crash course in energy.
For review: 1 kilowatt (kW) = 1,000 watts. 1 megawatt = 1,000,000 (1 million) watts. 1 gigawatt = 1,000,000,000 (1 billion) watts.
Energy is the ability to do work. Humans can perform work, and we do so by metabolizing food for kinetic energy. But we are quite limited in our output, producing only 100 watts at rest, 300-400 watts over sustained periods of time, and up to 2 kW in short bursts, like sprinting (http://large.stanford.edu/courses/2014/ph240/labonta1/). For most of our existence on this planet, we were hunter gatherers, chasing game and foraging. When we adopted an agrarian lifestyle roughly 10,000 years ago, we domesticated animals to assist us in performing labor for the purposes of planting and harvesting crops. Draught animals like horses and oxen can sustain 600-1,000 watts of power on average, also with bursts up to 2 kW (https://www.sciencedirect.com/topics/earth-and-planetary-sciences/draught-animal). An improvement upon the limits of human labor, to be sure, but a small improvement.
Then we invented windmills about 3,700 years ago, mostly for crushing and milling grain and pumping water (www.historyofwindmills.com). Capturing wind is ancient technology. Humans have literally sailed the world for millennia, and traditional windmills generated about 14kW of usable power, which allowed for more food production and spurred population growth (https://www.google.com/amp/s/www.sciencefocus.com/future-technology/how-does-the-power-output-of-a-traditional-windmill-compare-to-a-modern-wind-turbine/amp/).
The invention of the (coal-powered) steam engine marked the beginning of the Industrial Revolution and completely altered the way humans lived and worked. Steam had been used for various purposes in previous centuries, but became a commercially successful technology capable of performing mechanical work in 1712 due to developments made by Thomas Newcomen, and later, improvements made by James Watt (https://en.wikipedia.org/wiki/History_of_the_steam_engine). Suddenly we had engines cranking out up to 1800 kW of power! Steamships appeared, then steam locomotives crisscrossed industrialized nations, and steam-powered machinery became commonplace in factories. Our consumption of coal fueled our growth, and our growth fueled our consumption.
Most electricity in the U.S. (and the world) is produced by turbine generators which use a fluid (air, steam, water, combustion gases) to move a series of blades mounted on a motor shaft (https://www.eia.gov/energyexplained/electricity/how-electricity-is-generated.php). The generator then converts the kinetic energy of the moving blades into electrical energy. Power plants burn coal or natural gas to generate steam to turn the turbine. Nuclear power plants generate heat and steam through the process of fission (atoms splitting apart), which then turns the turbine. Hydroelectric dams turn the turbine with the power of flowing water. Modern day wind turbines use the energy from air currents. It’s the same design recycled again and again, powered by different fluids and fuels.
Now let’s talk numbers. There are multiple units for energy (watts, joules) but we tend to standardize to “watt-hours”. A kilowatt hour (kWh) is 1 hour of electricity usage at a rate of 1 kW, but this can be scaled up to be megawatt hours or gigawatt hours (https://ourworldindata.org/scale-for-electricity).
A standard coal power plant is about 500 mW in size and can crank out 3.5 billion kWh per year, which is utterly massive in scale and demonstrates just how dependent we are upon fossil fuels for our electricity (https://www.mcginley.co.uk/news/how-much-of-each-energy-source-does-it-take-to-power-your-home/bp254/). In 2020, about 4,007 billion kilowatthours (kWh) (or about 4.01 trillion kWh) of electricity were generated at utility-scale electricity generation facilities in the United States (https://www.eia.gov/tools/faqs/faq.php?id=427&t=3) and more than half of this total resulted from the combustion of fossil fuels. When one examines the staggering amount of energy we consume, it should be no surprise that atmospheric CO2 has risen, and will continue to rise, exponentially unless we choose to decarbonize our electrical grid.
I won’t bore you with more mind-boggling numbers, but I will leave you with this parting thought: we CANNOT continue to exploit, pollute, pillage and plunder this planet. We will perish if we do. And I don’t mean individuals will perish. I mean the human species and upwards of 90% of life on Earth will go extinct.
We always have a choice. We live in the most technologically advanced age of our existence. We must reduce consumption and we must harvest our energy from renewable sources. We can always choose to be part of the solution.