We often mention the near billion people who have no access to electricity. The UN sees progress by counting electric power connections that deliver trivial or part time electricity. Robert Bryce in A Question of Power points out that ample energy is required to improve lifestyles and develop industry and commerce. He notes that an ordinary household refrigerator requires more power than 3 billion people can access. Ample energy enabled the industrial revolution. The steam engine helped pump water out of coal mines, providing England with coal-sourced energy just as their forests were demolished by wood burning. Coal is still a major source of world energy. The discovery of petroleum enabled a more convenient, liquid source of energy. Burning fossil fuels is now essential to power modern civilization. We also know that burning fossil fuels adds CO2 gas to the atmosphere, absorbing outbound infrared radiation, slowly warming the planet.
If we can use a combustion alternative that is cheap and reliable, we can upgrade the lifestyles of billions of people in developing nations while also reducing CO2 emissions. Atomic fission can be that source of energy, if we also find ways to use electricity to power the industrial, commercial, residential, and transportation functions in our civilization. Electrify everything is the theme of Electrify Our World, presented in these scrolls.
Energy basics are the few bits you should know to participate in analyzing or formulating energy policy, like the difference between power and energy.
Climate change is briefly reviewed, along with the importance of energy to civilization and population. The practical potential benefit of renewable energy from sun, wind, and rain is quantified.
Energy grand strategy traces the potential future global energy flow through heat, electricity, hydrogen, and ammonia to satisfy world needs without burning fossil fuels.
Mass produced fission power plants can be produced by the shipyard industry fast enough to meet the future zero-CO2 vision by mid-century.
Fear of radiation must be overcome by people, politicians, and regulators to unleash the potential of atomic fission.
Hydrogen from water can capture and extend electricity’s energy into transportation and industry.
Electric vehicle adoption is already accelerating, but pressuring natural resources for battery materials.
Heavy vehicles can’t economically also haul heavy batteries, so hydrogen may power some transportation.
Ammonia from air, water, and electricity is critical to agriculture and may power transport and shipping.
Building cooling and heating will use much electricity. New industrial processes such as iron electrolysis may replace blast furnaces. We must create energy policies that are economically acceptable.
Heat is not as valuable as useful energy. These forms of useful energy can be transformed between each other with modest energy losses. Kinetic energy is mass in motion. Dropping a rock transforms its gravitational potential energy into kinetic energy as it speeds to the ground. Energy can be stored or transmitted in electric and magnetic fields.
Work has a specific definition. Pushing an object 1 meter against 1 newton of force uses 1 joule of Work energy. On earth a kilogram of mass exerts a force of 9.8 newtons.
Joules are the standard scientific unit for energy. One watt is one ampere of electric current flowing across a potential of one volt. A joule is one watt-second. These scroll presentations will use standard scientific units. We’ll avoid feet, inches, Fahrenheit, miles, gallons, BTU, acres, etc.
The box represents a container of many gas molecules bouncing around, hitting each other and the sides of the container. Of course there are many more; just a gram of hydrogen gas has millions of billions of billions of molecules. Each has energy m*v**2/2, but they can’t be harnessed en mass for useful energy. We do know that heat flows from hot to cold, from your warm home through the walls to the cold winter air, and from your warm body to the swimming pool water. We can harvest energy from that heat flow, analogously to harvesting energy from water flowing down a water wheel.
The heat engine was commercialized by James Watt and others over 300 years ago, powering up the industrial revolution. Symbolically, on the left is a hot body at temperature T-hot; on the right is a cold body at temperature T-cold. Q-hot is the quantity of heat flowing into the interposed Heat Engine; Q-cold is the quantity of heat leaving it. The heat engine extracts Work — kinetic energy.
How much Work can be extracted from the heat flow Q-hot? It depends on the design of the Heat Engine, but there is an efficiency limit, termed Carnot’s theorem. Work extracted is proportionate to temperature drop, In to Out. For example, what is the max work that can be extracted from water as hot as it can get (without boiling) to as cold as it can be (without freezing)? We often denote temperatures in Celsius (C) degrees, but energy calculations use Kelvin (K) degrees above absolute zero — the temperature so cold that individual molecules have no motion. Zero degrees Celsius is 273 degrees Kelvin. The temperature unit sizes (C or K) are the same. In this example there is a 100 degree difference hot to cold. Keep in mind that the 27% efficiency is the maximum that can be extracted by the cleverest engineers.
Scientists and engineers have spent three centuries optimizing the design of heat engines, to maximize the Work extracted from Heat flowing from Hot to Cold. In a modern power plant, the heat engine is the biggest, most expensive part. The heat source may be combustion in coal-fired or gas-fired plants, or fission in plants such as ThorCon.
To maximize efficiency in a oil/gas/fission/coal thermal power plant, make the T-hot heat source temperature as high as materials can withstand, and choose a T-cold heat sink as cold as available without overheating it. The most efficient plants’ heat sinks are flowing river, lake, or ocean water. Evaporative cooling towers are less effective heat sinks that actually consume water. Air-cooled plants are least efficient.
Remember that heat engines don’t convert Heat energy to Work energy; rather they tap the flow of heat energy to produce Work. There must be a heat flow output, Qc. Engineers call Qc rejected heat; detractors call it waste heat.
Instead of maximizing power plant efficiency, the plant can be designed to use rejected heat for purposes such as heating of nearby buildings. This is termed co-generation. For example, Dartmouth’s oil-burning electric generation plant also heats steam and water circulating in tunnels beneath the campus to many college buildings.
A heat pump is a heat engine in reverse. It consumes useful Work energy from an electric motor to increase the temperature of heat flowing from a cold heat source to a hot heat sink. Heat pumps can be effective for ordinary home heating in temperate climates because the needed temperature increase is modest. Increasing temperature 15 degrees from 5C outside to 20C inside is a bump from 278K to 293K, about 5% relative to thermodynamic zero (-273C).
The ratio of the heat energy added to the electric energy used is the coefficient of performance (COP).
The LG window air conditioner pumps heat from your room to air outdoors, even though the outdoor air heat sink is hotter than your room air.
The Mitsubishi air source heat pump pumps heat in either direction, cooling or heating the room air, as needed. It’s coefficient of performance is the ratio of thermal power added, kW(t), to electric power used, kW(e).
If outside air temperature is 55F (41C, 314K) the Mitsubishi can heat the room with 7 kW(t) at a COP ~ 4, consuming only 1.75 kW(e) of electricity. When outside air temperature drops to 5F (- 17C, 256K) the heating drops to 3 kW(t), consuming 1 kW(e) at a COP ~ 3. So though the COP stays reasonably high, the heating capability drops considerably in cold weather.
Mitsubishi has dozens of heat pump products, with varying specs.
Power is the flow of energy. It is energy per unit of time. Energy is measured in joules. Power is measured in joules/second, termed watts.
Watts are common measures of not only electric power, but also kinetic energy per unit time. My son-in-law enjoys training on his bicycle, which is equipped with a bluetooth-connected transducer on the pedal crank. The computer uses torque (force) and rotations (distance), to compute Work and display average kinetic power (218 watts) and total energy expended (2068 kilojoules).
Here’s my electricity bill. Let’s go over the bill, line by line. The member service charge of 29.32 is the fixed monthly fee to be connected to the grid, with rights to consume energy at a rate of up to 96 kW. That’s quite a lot of power; it would entail 400 amperes at 240 volts. Most homes have wiring and circuit breakers set up for 100 or 200 amps max. Future residential demand may increase; a Tesla home charger takes 80 amps, or 19 kW. Remember the 29.32 just pays for the right to buy energy at a power level up to 96 kW, not for the electric energy itself, detailed in the following lines.
The delivery charge for 632 kWh during the month is 25.48, for the service of sending the electricity through the distribution network including substations, distribution power lines, and neighborhood power lines along streets. It covers costs for sending crews out to fix tree-downed power outages, for example.
The system benefit charge of 4.29 is for grant programs, such as paying to retire old refrigerators.
The regional access charge of 17.10 is for the use of the high voltage transmission lines connecting generating suppliers to the Co-op substations, from which the electricity is distributed.
The Co-op doesn’t generate electricity; it buys it from generating suppliers connected to the grid. The 41.81 is the charge proportionate to the energy used, allocated at the average rate of 6.615 cents/kWh.
No credible person would say Burlington VT is 65 miles per hour away from Hanover NH. 65 miles per hour is a speed, a rate of change of distance. 65 miles is a distance. Such a statement should erase all credibility of the writer or speaker.
How credible should be a writer who attempts to describe stored energy in units of energy per unit time? Should nonsense-spewers participate in setting energy policy?
“The California Independent System Operator Corporation (CAISO) operates about 80% of the bulk of the state’s wholesale transmission grid”. California’s ISO made the above nonsense statement. Do you think they are competent to operate the grid?
The LA Times reporter describes energy storage in power units. Nonsense!
General ignorance contributes to California’s energy problems.
Sometimes people confuse thermal power and electric power. I’ve seen 1000 watts of thermal power written as 1 kW, or 1kW(t), or 1 kWt, or 1 kWth. To avoid confusion, we use such a suffix when a topic includes both thermal and electric power.
A typical power plant (heat engine) may have a 33% efficiency converting heat to electricity. The rest is rejected to a heat sink — the environment, often water. Power plants have undergone engineering improvements for 300 years to achieve this efficiency.
Conversely, changing electricity to heat is simple and 100% efficient, by running current through a resistor, such as the spiral heating element on a stove top. Ultimately, all the electricity consumed by your TV, refrigerator, food mixer, and lighting is transformed to heat. All such heat eventually flows to the ultimate heat sink. the planet Earth, which itself radiates heat away as infrared radiation to outer space.
The 80 watts (average) your refrigerator consumes heats your home a bit, via the refrigerators’s warm radiator. It’s located on the back, or beneath, or sometimes built in to the external case. In warm climates this makes the home air conditioner work a bit harder to remove that 80 watts of heat.
Useful energy is fleeting. The kinetic energy of a coasting bicycle dissipates as it slows down from friction with passing air, friction of moving bearings, and from the give and take of the rubber tire flexing as the wheel rolls on the road. A stovetop heating element converts electric energy directly to heat energy.
Electric energy is much more useful and valuable than heat energy, so it makes little sense to add their values together, even if both are measured in watts.
These examples remind that power is the flow of energy from one form to another.
Starting in Berkeley, California is beginning to ban natural gas, first in new buildings. The politicians and environmentalists don’t understand that this will increase CO2 emissions. Substituting electric heating for burning natural gas will not help because most electricity is generated by burning natural gas, with a conversion efficiency of ~33%. If electricity were generated by zero-CO2 sources such as hydro, fission, wind or solar, such an ordinance might help.
When people cook dinner, the sun is setting. The incremental electricity demand from turning on electric stoves is always met by adding a bit more natural gas to combustion turbines that power most of California.
The New York Times is similarly bamboozled. This article also promotes electric stoves with induction heating using specialized metal pots rather than resistive heating elements, which use marginally more electricity because some heated air flows around the pot.
Most reporters know less about energy than you do now.
Reporters may not understand the difference between energy and power (energy per unit time), nor the value difference between electric energy and thermal energy. They often report what they are told. You may have to guess what the facts really are, and perhaps write a note questioning the reporting.
In these scrolls, we will present energy facts in multiples of power units (watts). Watts are joules per second. So for example a watt-hour is 3600 watt-seconds. A kilowatt-hour (kWh) is 3,600,000 watt seconds. A megawatt is 1000 kilowatts (1 MW = 1000 kW). A gigawatt is 1000 megawatts (1 GW = 1000 MW = 1,000,000 kW = 1,000,000,000 W).
Confusion avoidance. These scrolls will avoid non-scientific units like BTU (1055 watt-seconds), or MMBTU (1,000,000 BTU). Note the oil and gas industry use M to mean kilo, not mega. One horsepower is 746 watts. 1 MTOE is the energy from burning a million tonnes of oil, or 41,868 megajoules, or 11.63 megawatt-hours. 1 tonne = 1000 kg. 1 million tonnes might be 1 Mt, and 1 MMt sometimes means one million metric tons. Sometimes people write 1 Mg to represent 1000 kilograms. We’ll stick with multiples of watts and watt-hours.
It’s difficult to envision the scale of power requirements. The US consumes an average of 500 GW of electric power, 24 hours per day, 365 days per year. Pictured are ways to generate 1 GW of power, if the sun is shining fully or the wind is blowing optimally.
Return to Electrifying Our World.