It Takes Energy to Make Energy

Energy Sources of Electricity
The United States’ power grid comprises an extensive network of power plants, substations, transmission lines, and distribution lines, which are constructed and maintained using fossil fuels. Electricity is generated primarily from fossil fuels (60.2%) and nuclear energy (18.2%). These traditional energy sources are neither sustainable nor environmentally safe. Renewable energy sources such as hydropower, wind, and solar energy generate only a small fraction of the total electricity in the US – 6%, 10.3%, and 3.3%, respectively. While hydropower is a renewable energy source that can produce baseload power 24/7, it is subject to droughts. Solar and wind farms have low capacity factors of 28% and 35%, respectively, and require backup power plants (mostly fossil-fueled) to provide baseload power. (Source: US Energy Information Administration).

Energy Losses
Electric power plants have an average efficiency of around 35% to 45%. However, transmission, distribution and grid infrastructure components add another 10% loss. Additionally, the EV charger adds yet another 15% loss. This means that around 85% of the electrical energy is wasted before the vehicle is even used. The EV electric motor efficiency, which is around 90%, adds yet another 10% loss. It is important to note that the energy used for the extraction, production, and transportation of primary fuel sources is not included in this calculation.

Energy Returned on Energy Invested
The Energy Returned on Energy Invested (EROEI) is a measure that calculates the ratio of energy output to the energy input for a primary fuel source, taking into account the energy required for extraction, processing, and transport. A higher EROEI indicates that more energy output can be generated with a lower input, while a lower EROEI indicates that more energy input is needed to produce a lower output. As fuel sources become scarcer, the EROEI decreases, which means that more and more energy will be needed to produce energy (electricity). In the next few decades, it will be increasingly difficult to power the electrical grid as all the easily recoverable high-quality oil and gas reserves will have been depleted. The remaining reserves of oil and gas will require significantly more energy to extract and produce, that will ultimately end in a net energy cliff.

Sustainability
The Energy Return on Investment (EROI) ratio is a measure of the energy produced to the energy required to create it. Back in the 1930s, oil had an EROI of around 100:1, and natural gas was higher. However, today’s oil and gas fields have an average EROI ratio of around 20:1. Solar and wind farms, which have low capacity factors and high transmission losses, depend on these primary energy sources to provide 24/7 baseload power to consumers. In the coming 20 years, the question is not whether the electrical grid can cope with extra demand from EVs, which use as much energy as a home’s central air conditioner, but whether the grid’s generating capacity can be maintained at current levels.

Transmission and Distribution Lines
The electrical grid in the United States is a massive system consisting of more than 10,000 utility-scale power plants, according to the U.S. EIA. This network comprises 200,000 miles of high-voltage transmission lines, 5 million miles of low-voltage power lines, 50,000 substations, towers, and utility poles, as well as various distribution transformers. The electricity is provided to 145 million end-users, and it must be produced as it is consumed. The grid’s operation and maintenance not only consumes energy but also has an impact on the environment and health. The removal and trimming of trees around power lines, for instance, require the use of trucks, chainsaws, and wood chippers. Trees not only provide shade but also air and water filtration, oxygen production, and carbon dioxide absorption, which is a greenhouse gas (GHG).

Grid Capacity
In 2019, the United States generated 4,118 billion kWh of electricity, according to the EIA. If there were 100 million electric cars on the road, each partially charged (20 kWh) daily, energy consumption would increase by over 2.5 billion kWh per day (including losses), or 912 billion kWh per year. To supply this additional electricity, the nation’s grid output would need to increase by over 22%, not including the energy used to extract and transport fuel sources to power plants. Assuming that electric vehicle charging would be evenly distributed throughout the day, which is unlikely, this increase in electricity demand will eventually overload the electrical grid, leading to blackouts, particularly in the summer. A Level 2 charger, which is commonly used for electric vehicles, draws around 7,200 watts, more than a central air conditioning unit (4,000 watts) for a 2,500 sq. ft. home. Furthermore, the carrying capacity of power lines decreases during summer when the air temperature rises, causing transmission and distribution (T&D) power lines to become less efficient by around 5%.

Capacity Factors
A power plant’s capacity factor is the average amount of electricity it generates over a year, as opposed to its maximum output capacity or name plate capacity. Regardless of the type of power plant or renewable energy source, maintenance and outages can occur, which may affect its productivity. Additionally, renewable sources are also subject to the availability of natural resources.

U.S. Capacity Factor by Energy Source in 2021
Nuclear 92.7
Geothermal 71
Natural Gas 54.4
Coal 49.3
Hydropower 37.1
Wind 34.6
Solar PV 24.6
Source: U.S. Energy Information Administration

Renewable energy sources like hydropower, solar, and wind have limitations when it comes to providing uninterrupted power supply. Hydropower depends on the availability of water, which can vary season to season. Solar energy production is limited to daylight hours, and wind turbines require sufficient wind speed, usually between 30-55 mph. On the other hand, nuclear energy, natural gas, and coal-fired power plants are capable of generating uninterrupted power 24/7/365.

Electric Vehicle Efficiency
The efficiency and emissions of an electric vehicle are influenced by the primary fuel source used to generate its power. This includes all the steps involved in the full-fuel-cycle, such as extraction, mining, processing, and fuel delivery to the plant and its end use. To generate 100 kWh of electricity, 112 lbs. of coal or 736 cubic feet of natural gas needs to be burned at the plant (33% and 35% efficiencies respectively). Additional power plant output is required to make up for power line and charger to EV battery losses (7% and 20% respectively). When combined with the EV motor efficiency of 90%, the overall EV efficiency drops to under 23%, which doesn’t include the energy needed to produce the fuel sources. As far as costs, fully charging a 100 kWh EV battery at level 2 takes over 16.5 hours and costs around $36 in California. The pros and cons of various fuel sources used for generating electricity are further explored below, along with the overall EV efficiency when using these fuel sources.

Coal

Efficiency
Coal-powered plant efficiency (33%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor efficiency (90%) = 22.09% overall EV efficiency.
Does not include: (a) energy used to mine and transport coal to the power plant.

Fully charging a 100 kWh battery pack requires generating 100 kWh at the power plant burning around 112 lbs. of coal. Additional coal is needed to make up for power line losses and charger to EV battery losses (7% and 20% respectively), a total of around 142 lbs. of coal.
(Coal–1.12 pounds/kWh. Source: U.S. Energy Information Administration)

Sustainability
According to the EIA U.S., coal reserves would last about 332 years. Link: How much coal is in the United States?

Pros
A cheap, plentiful, and reliable source of energy. Several technologies can be used for mitigating emissions at the smoke stack and using higher energy density coal like Anthracite which has fewer impurities as opposed to Bituminous, Sub-bituminous, or Lignite.

Cons
Produces the most CO2 per BTU thereby the largest contributor to global warming. Coal also releases dozens of chemicals hazardous to the environment and our health. When mercury enters the oceans, lakes, and rivers it gets converted by bacteria into methyl mercury which is a highly toxic form of mercury that has polluted virtually every fish in the U.S. causing the EPA to issue limitations on consuming fish. Clean coal technologies do not remove mercury from the smoke stack. More information on the types of coal can be found on the U.S. Energy Information Administration website. More than a dozen states still rely on coal for generating most of their electricity.

Natural Gas

Efficiency
Gas-powered (simple cycle) plant efficiency (35%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 23.43% overall EV efficiency.
Does not include: (a) energy used to extract, produce, or transport gas to the plant.

Gas-powered (combined cycle) plant efficiency (60%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 40.17% overall EV efficiency.
Does not include the energy used to extract, produce, and transport gas to the power plant.

Fully charging a 100 kWh battery pack requires generating 100 kWh at the power plant burning around 736 cubic feet of natural gas. Additional gas is needed to make up for power line losses and charger to EV battery losses (7% and 20% respectively), a total of around 935 cubic feet of natural gas.
(Natural gas–7.36 cubic feet/kWh. Source: U.S. Energy Information Administration)

Sustainability
According to the EIA, the United States has enough dry natural gas to last about 80 years. Link: How much natural gas does the United States have, and how long will it last?

Pros
Natural gas (methane) is a clean burning fossil fuel at the smoke stack that emits negligible pollutants and over 50% less carbon dioxide (CO2) than coal when used in an efficient natural gas power plant. More coal-powered plants are switching to natural gas.

Cons
Natural gas is methane, a greenhouse gas (GHG) around 30 times stronger than carbon dioxide (CO2) at trapping heat. Hydraulic fracking can release CO2 and methane into the atmosphere offsetting the benefits of gas. Hydraulic fracturing (fracking) is a water-intensive process that uses around 2-8 million gallons of water and hazardous chemicals for each fracking cycle. Various toxic chemicals are used and may include kerosene, benzene, toluene, xylene, and formaldehyde to name a few out of the hundreds of hydraulic fracturing chemicals. Flow-back (polluted water that flows back to the surface along with oil, gas, brine, and other hazardous chemicals when the well is produced) is another issue. An estimated 90% of flow-back in the U. S. is disposed of in deep EPA-licensed Class II disposal wells. According to the EIA, there are over 480,000 natural gas-producing wells in the U.S. That’s a lot of flow-back water to safely store. In addition, water filtration plants were not designed to deal with polluted flow-back water.

Nuclear Energy

Efficiency
Nuclear power plant efficiency (Pressurized water reactor) (35%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 23.43% overall EV efficiency.
Does not include: (a) energy used for front-end steps that include mining and producing enriched uranium for use in nuclear reactors and (b) back-end steps to safely manage, prepare, and dispose of highly radioactive spent nuclear fuel rods.

According to the Nuclear Energy Institute, one uranium fuel pellet creates as much energy as one ton of coal, 149 gallons of oil or 17,000 cubic feet of natural gas, which is approximately 1,400 kWh. Accounting for power plant, grid and EV charger losses, one pellet can charge a 100 kWh battery around 11 times.

Sustainability
According to the U.S. EIA, based on average 1999-2008 consumption levels (uranium in fuel assemblies loaded into nuclear reactors), uranium reserves available at up to $100 per pound of U3O8 represented approximately 23 years’ worth of demand, while uranium reserves at up to $50 per pound of U3O8 represented about 10 years worth of demand. Domestic U.S. uranium production however supplies only about 10 percent on average of U.S. requirements for nuclear fuel, so the effective years’ supply of domestic uranium reserves is much higher, under current market conditions. Worldwide estimates for uranium’s sustainability range from 80-200 years. Source: Energy Information Administration (EIA).

Pros
Great for navy ships and submarines.

Cons
Depending on the source, the energy return on energy invested (EROEI) for nuclear energy is in the single digits. While it may be near zero emissions at the power plant, the Full-Fuel-Cycle for nuclear energy is highly complex and energy-intensive and includes:

The front-end: Steps required to produce uranium fuel rods. Uranium mining produces immense amounts of uranium mill tailings containing over a dozen radioactive nuclides that can enter the food chain, and water supply or is carried by the wind from dried radioactive sand in addition to leaving heavy metals, toxins, and radioactive waste in our air, soil, food, and water for thousands of years to come. Nuclear power can never be safe or cheap. Issues range from accidents, and natural disasters (Fukushima Daiichi Nuclear Power Plant) to terrorism. The U.S. National Institute of Health has several articles on the environmental and health impacts of uranium mining, one is from Dr. Dale Dewar on Uranium mining and health.

The back-end: Decommissioning which can take 60 years, and long-term storage of contaminated buildings, components, and spent fuel pellets in addition to cleaning up the uranium mine. Hot (around 2800°C) and highly radioactive spent fuel rods must first be cooled in a spent fuel pool for around 5 years, then dry stored in casks for over 10,000 years. More information on decommissioning is available on the U.S. Energy Information Administration’s website.

The cost: Spent reactor fuel pellets/rods remain dangerously radioactive for around 10,000 years. Decontamination, decommissioning, and radioactive waste storage costs are now estimated at over $187 billion (2016 figure) and rising.

This entire process is energy- intensive and produces highly toxic chemicals and radioactive waste that remains hazardous for hundreds of thousands of years. And since the nuclear fuel cycle is geographically dispersed, it creates multiple exposure pathways that pose persistent risks and safety concerns over time-spans beyond human experience.

The risks: Other issues include accidents, terrorist attacks, or natural disasters such as Japan’s Fukushima Daiichi Nuclear Power Plant which is leaking highly radioactive water into the Pacific Ocean and will take around 40 years to be decommissioned. A comprehensive article by Richard C. Ausness from the University of Kentucky College of Law titled “High-Level Radioactive Waste Management: The Nuclear Dilemma” describes issues associated with the nuclear fuel cycle. Link: http://large.stanford.edu/courses/2017/ph241/koob2/docs/ausness.pdf 

Oil

Efficiency
Oil-fired power plant efficiency (38%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 25.44% overall EV efficiency.
Does not include energy used to extract, refine or transport oil to the plant.

Sustainability
Global crude oil proven reserves are estimated at around 1,300 billion barrels equivalent to around 43 cubic miles of oil. At the rate of consumption (1 cubic mile of oil or 2.62 billion barrels per year), a little over 40 years. The United States alone holds over 35 billion barrels of proven reserves, enough to last a little over 5 years.

According to the U.S. EIA, the global supply of crude oil, other liquid hydrocarbons, and biofuels is expected to be adequate to meet the world’s demand for liquid fuels through 2050.

Pros
A reliable source of energy with very high energy density.

Cons
All petroleum products are harmful to human health and the environment. Source: Wikipedia Environmental impact of the petroleum industry.

Biomass and Waste Fuels

Efficiency
Efficiency varies depending on the type of biomass or waste fuel. Corn ethanol for example has a negative efficiency.

Pros
Waste fuels such as landfill gas contain about 50% carbon dioxide (CO2) and 50% methane (CH4) from decomposing organic material and are a major source of CH4 emissions in the United States. Emission controls that capture and use landfill CH4 as a power source for generating electricity are utilizing an effective CH4 reduction strategy. CH4 is roughly 30 times more effective as a heat-trapping gas than carbon dioxide (CO2). Landfill gas also provided nearly 16% of 2016 biomass-generated electricity.

Cons
Using biomass for energy can have positive and negative effects. Ethanol production for example takes more energy (around 70 percent more) to make from grain than the energy in ethanol. Around 1 acre of land is needed to produce 328 gallons of ethanol. In addition, ethanol has a lower energy content than gasoline (around one-third fewer BTUs) which lowers your gas mileage. All of the biomass and waste fuels together made up only 2% of total U.S. electricity generation in 2016.

Hydropower

Efficiency
Hydroelectric power plant efficiency (90%) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 60.26% overall EV efficiency.

Sustainability
Sustainable as long as there is sufficient water.

Pros
The best source of clean and efficient renewable energy. Hydroelectric plants in the Columbia River Basin supply most of the electrical energy needs to residents in Idaho, Washington, and Oregon, with enough energy to supply around 8 million homes.

Cons
Hydroelectric power is dependent on water. Hydropower in California on average provides around 18% of the state’s electricity per year. In the most recent year less than 7% of total electricity was generated in-state due to drought, with reservoirs being at record low levels. Expansion may also be limited as there are growing environmental, economic, and political constraints. Water reservoirs emit carbon dioxide and methane from decaying vegetation, nutrient runoff, and soil erosion. New studies reveal that the carbon footprint of hydropower is higher than previously assumed. In addition, fish, especially salmon in the Northwest, have been devastated by reservoirs, dams, and hydroelectric plants.

Geothermal

Efficiency
Geothermal powered plant efficiency (12% worldwide average) x T&D losses (93%) x AC to DC battery charger losses (80%) x EV electric motor (90%) = 8.03% overall EV efficiency.

Pros
Geothermal energy can be a very environmentally friendly source of energy. Geothermal power plants do not burn fuel to generate electricity so the levels of air pollutants they emit are low emitting 97% fewer sulfur compounds and about 99% less carbon dioxide than fossil-fueled power plants of similar size and can provide energy 365 days a year.

Cons
According to the EIA geothermal plants can be very site-specific and have generally been limited to areas with accessible deposits of high-temperature groundwater near the surface of the planet. Significant exploration and production risks can result in high development costs. Local cooling can degrade the plant’s generating capacity over time. The total geothermal electricity generation was 0.4% of the total U.S. utility-scale electricity generation. The U.S. has large geothermal resources, but growth is much slower than wind or solar.

Solar Power

Efficiency
Between 15% and 20% with higher-end solar cell efficiency exceeding 22%.

Sustainability
For as long as there is solar energy and long-life solar cells.

Pros
Clean source of renewable energy. More reliable than wind energy.

Cons
Solar farms have to be configured in a two-phase operation. When the Sun stops shining a backup power source is needed to provide a base load power to consumers. Solar farms are also vulnerable to damage from adverse weather, such as a hail storm, that in 2024, destroyed a 4,000 acre solar farm in Damon, Texas.

Wind Power

Efficiency
Between 35-45%.

Pros
A good source of clean renewable energy.

Cons
Wind power is an intermittent source of energy. In order to provide baseload power, it has to be configured in a two-phase operation. Wind farm turbines also need to be spaced far apart, between 8 and 12 times the rotor diameter, and are often located in remote locations, which can result in significant transmission and distribution (T&D) losses.

Other issues include bird collisions, killing between 140,000 and 500,000 birds every year from wind turbine collisions. Blade tips can reach speeds of 180 mph which can easily cut off a raptor’s wing. Hawks, eagles, and falcons are especially vulnerable due to their flight behaviors and size. (Source: U.S. Fish & Wildlife Service). Not to mention millions of bats and songbirds. Wind turbines have an average capacity factor of around 36%.

In addition, wind turbines lose efficiency every year due to leading edge blade erosion, caused by hitting raindrops, hail, ice, bird strikes, insects, salt, etc., at speeds of up to 180 mph, that results in gouges, delamination, cracks, or structural damage to the blades.

Other issues include unscheduled downtime due to lightning strikes, bearing, gearbox, yaw system, generator and inverter failures., which can effect a single turbine several times a year.

Transmission and Distribution

No matter what fuel source is used to generate electricity, it’s likely to be connected to the electrical grid. In the U.S. over 200,000 miles of high-voltage transmission lines and over 5.5 million miles of local low-voltage distribution lines deliver electricity to businesses, factories, homes, and charging stations that power electric cars. Transmission and distribution losses vary from state to state from 2.2% (WY) to 13.3% (ID). Additional losses due to hot summer days can incur an additional 5% loss. Energy is also used (mostly fossil fuels) to constantly repair, maintain and upgrade power lines.

Trees also have to be constantly pruned or cut down across the nation as falling branches/trees are the single largest cause of electric power outages. There are over 148,000 tree-trimming businesses across the U.S. Trees however are good for the environment and good for carbon sequestration and help keep the planet cool. Transmission and distribution lines also have a large impact on bird populations. The U.S. Fish & Wildlife Service estimates that each year up to 57 million birds are killed in the United States from collisions with electric utility lines alone.

Carbon Dioxide, Global Warming, and Sea Levels

The oceans, trees, and plants absorb most of the carbon dioxide (CO2) from fossil fuels with the rest remaining in the atmosphere for hundreds of years which is a greenhouse gas (GHG) that contributes to global warming. More info can be found on NASA’s website. The EIA also shows how much carbon dioxide is produced when different fuels are burned. Then there is the problem of sea levels. Data provided by NASA using satellite altimetry show levels rising at 3.3 millimeters per year. In 25 years (from 1993 to 2018) sea levels had risen a total of 88 mm (around 3.46 inches) and accelerating. Hopefully, renewable energies will play a bigger part in providing the world’s energy needs of the future.

Challenges Facing EVs

EVs can be green if they’re powered directly by clean energy such as hydropower, wind or solar energy. Used on a large scale would significantly reduce transportation’s role in GHG emissions which contribute to Global Climate Change and Global Warming. Unfortunately, only a few states in the U.S. have an abundance of clean renewable energy sources. Most other states and countries will still rely on fossil and nuclear-fueled power plants for the foreseeable future as renewables have their limitations. In addition, the world’s energy usage is projected to increase by around 50% by 2050. Source: EIA.