We tend to imagine an electric car must be good for the environment because, for one thing, it doesn’t burn gasoline. And in many people’s minds, this automatically means electric vehicles don’t cause emissions like gasoline-powered vehicles do. They use only electricity, something seen by many as “clean energy”.
From a cost perspective, you may hear electric vehicles can be cheaper to operate than gasoline powered vehicles. As a matter of fact, if it weren’t for the high price of electric cars and their limited range between charges, more people would have had one by now. Would that be a good thing?
Are electric vehicles better for the environment than cars with gasoline engines?
Are electric cars emission-free?
Can we convert all electric power generation in the world to wind and solar and drive nothing but electric vehicles?
What exactly happens when you plug in an electric car to charge it?
These are intriguing questions, to which the answers are not straight forward.
Unfortunately, one is hard pressed to find something in the media that can answer any of those questions objectively. Many of the arguments for AND against electric cars tend to be influenced by commercial, political or ideological interests.
To search for answers, we must consider the hidden scientific principles involved. If you are reading this, you are likely someone who prefers to know the facts rather than watch YouTube snippets by folks who love or hate electric cars.
For starters, if I asked you: which car uses more fuel from the primary source of energy, an electric car or a similar-size gasoline car, would you know? We can’t answer that without delving into the subject of Efficiency. Similarly, we can’t answer the question of how much wind and solar we can put on the grid without understanding the concepts of Momentum and Generation Reserve, two of the most crucial aspects of an electric grid. Get ready for a major detour. I hope you don’t get discouraged and move on. Please continue to read. We are not getting off the topic of electric cars. We are smack into it!
How Does An Electric Car Work?
An electric car is a battery operated vehicle. The battery operates an electric motor, which turns the wheels of the car through a transmission, much like a traditional gasoline powered car. An electric vehicle can travel about 300 km (say, 200 miles) on a full charge. After that it stops and must be recharged to run again.
Makers of electric cars invest large sums of money in charging stations, where one can plug in their car for a few hours to recharge the battery. Charging stations are specialized electric outlets that have higher capacity than the household outlet. Some were free for a while, as a temporary promotion of electric cars. You can still charge an electric vehicle by a household outlet, but it would take a very long time. More on that later.
The bottom line is, the energy that moves the electric vehicle must come from the power grid somehow.
What is Electricity?
Here is a simple question. What do the following items have in common: light, radar, Wi-Fi, Bluetooth and Electricity? Answer: they are all waves, classified in physics as Electromagnetic waves. Scary? Not necessarily. It is just a long word that shouldn’t scare you. Electromagnetic waves are part of our daily lives and have been for many decades, just think of Wi-Fi, radio and TV and how often you use them. These waves travel in space at the incredible speed of light of 300,000 km per second. Yes, three hundred thousand kilometers in one second. This explains how you can talk on the phone with someone across the ocean as if you are in the same room with them.
In our daily use, Electromagnetic waves carry energy from a source to a point where the energy is used. For instance, a radio station broadcasts a wave, which we would call signal, into the air. The antenna in your car receives it and passes it on to the radio, where it is decoded to extract music, talk or whatever the radio station is broadcasting.
How Fast Does Electricity Travel?
Electricity waves propagate from power generating stations through a network of power lines and other equipment, known collectively as the electric grid. Electromagnetic waves travel in vacuum at the full speed of light. But in an electric grid, the waves of Electricity travel through wires and other metallic parts instead of vacuum. This slows them down slightly to about 90% of the full speed of light , or about 270,000 km/sec. Still incredibly fast. By the time you blink your eye once, electricity can go from New York City to Sidney, Australia, and back! Go ahead, blink.
Where Does My Electricity Come From?
Since electricity is only a wave, no particles travel from the power station to your home. No electrons, atoms or any form of matter. Nothing that we can mark or track! Only electromagnetic waves, spreading all over the grid by the effect of numerous generators simultaneously, be it coal fired plants, nuclear or wind turbines. A kaleidoscope of waves all intermingled together throughout the electric grid.
If you live in Seattle, USA, it means your home is connected to the North American Western Interconnection. It is a grid encompassing the western halves of Canada and USA, with thousands of connected generators. There is no telling if the electricity flowing into your toaster comes from a nuclear power generator in Arizona, USA, or a hydro power generator in British Columbia, Canada. Such is the wonder of electricity! The two eastern halves of USA and Canada are also connected together forming the North American Eastern Interconnection. Technical and physical challenges make it very difficult to connect the East and West systems together.
Beware of Snake Oil Salesmen!
You may be propositioned to receive/buy only “Green” or “Renewable” energy at your home or business. Anyone who claims they know where your electricity is generated is either grossly misinformed or deceptive. It is absolutely impossible to determine where or which generator on the grid produced the electricity arriving at your home or business. This is a FACT, which we want you to know and remember, especially when you get those glossy brochures enticing you to go green!.
How Electricity is Generated
Electricity is an energy carrier. Aside from lightning, which happens on its own in nature, electric energy must be “generated” by converting another form of energy to electricity. The long journey of the electric energy you receive at the outlet in your home starts at a power plant. A journey that includes many steps along the way, starting by generating the electricity, then channeling it through several gates before it can be used at your home. Most generating plants burn a fuel, like coal or natural gas, to produce heat. These are the two most common fuels (don’t worry, we will discuss other possibilities shortly). Heat is used in boilers to turn water into steam, which rotates a steam turbine. The turbine drives an electric generator. The rotating generator produces electricity and feeds it to a large network of wires that we know as the electric grid. Users plug into the grid at their convenience and use electricity to heat their home, charge the phone, keep the lights on, and so on. On a world-wide scale, 70-75% of the power plants use coal or natural gas to generate the steam.
In a nuclear power station, nuclear reaction generates heat, which produces the steam in the boilers to feed steam turbines. In a gas-turbine plant, natural gas (Methane) is compressed and ignited, producing force to directly rotate a gas-turbine driving a generator. At a hydro station, water flow rotates hydraulic turbines with attached generators. No worries, we will discuss wind and solar soon.
AC – DC
Clearly, the main objective in a power plant is to achieve rotation, because that is the most direct way to produce electricity in a form useable by society. It is called Alternating Current, or AC for short. An alternating form of electricity makes it possible to use Transformers. They are devices that can raise the voltage to as high as 750,000 volts and even higher. Higher voltages make it possible to transport large amounts of energy over long distances. Voltage is like the pressure in a pipe, the longer the distance the higher the voltage must be. Due to physical limitations, generators do not typically produce voltages higher than about 20,000 volts, which is not sufficient. Without transformers and High Voltage lines, it is impossible to have electricity except in close proximity to power plants.
As the name implies, Alternating Current means the electric current alternates (reverses) direction several times every second. The number of times the current reverses direction every second is called Frequency and is measured in cycles per second. The unit of frequency is Hertz (Hz), which is one cycle per second. If you see the text 50/60 Hz on your phone charger it means it can operate at 50 or 60 Hz. Only in North America the frequency is set to 60 Hz. The rest of the world uses 50 Hz.
Another form of electricity is Direct Current (DC). It is the form of electricity used in batteries, for example. It flows in one direction all the time and does not work with transformers. For this reason, electric grids operate exclusively with AC.
Each generator on the grid must rotate at a constant speed that is strictly and precisely controlled to stay constant. This is essential to keep all generators on a grid in unison (synchronism) and sustain constant “frequency” on the grid of 60 Hz in North America and 50 Hz elsewhere.
Momentum
If you have ever used an electric fan, you would have noticed that when you turn it off, it continues to rotate for a while before it stops. This is because energy is stored in its rotating parts as momentum. When you turn off the power, the stored energy continues to rotate the fan until it is dissipated, at which time the fan finally stops. The bigger and heavier the fan, the more energy it stores and the longer it takes to stop.
Let us say you are riding a bike that has a traditional light, the kind that gets its electricity from a dynamo on the rear wheel. If you stop pedaling for a moment, the bike will continue to move and the light stays on. But you are not putting any effort, so where is the energy to move you and bike coming from? It is the Momentum energy stored by the mass of the bike plus your own mass. The bike may slow down but it won’t stop immediately. Once you restart pedaling, you can regain your original speed. Although you slowed down a bit before regaining speed, the bike’s light never went off. And it is all because of momentum.
Why We Need Rotating Generators
On the electric grid, numerous rotating generators and turbines hold a great deal of stored energy as momentum of their massive rotating parts. They share the demand on the grid. If one generator fails and is taken off the grid, the remaining generators become overloaded and begin to slow down (just like the bike slowing down). However, the large momentum energy stored in their rotating parts prevents their speeds from dropping too fast. For a short time, power continues to flow from the remaining generators to the load and consumers don’t suffer an outage (just like the light of your bike staying on after you stop pedaling). In the meantime, automatic controls kick in very quickly to increase the fuel supply, steam or water flow, as the case maybe, to help the remaining generators regain their full speed (just like your starting to pedal again). Without such energy storage in the form of momentum, the electric grid would not remain intact during those crucial moments of the initial overload; and long blackouts would occur daily. The importance of generator-turbine momentum cannot be overemphasized.
Why are we bothering with the importance of momentum? Because as we will see later, most renewable sources of electricity do not contribute to momentum.
Reserve Capacity on a Grid
Demand on electric grids changes from moment to moment, as the “load” on the grid goes up and down regularly throughout the day. Even when you turn on one more light at home, the grid must react to that by increasing generation. It is a very intricately balanced dynamic system. To accommodate this, certain generators on the grid are operated below their maximum capacity on purpose. When demand goes up, those generators can increase their output in a fraction of a second to meet the increased demand. Rotational momentum plays a crucial role in making this process so smooth, customers on the grid never notice. We can go to the bike example again where the momentum kept the light on until the rider restarted pedaling.
Shortage of power may also be caused by a generator getting tripped off the grid. You would be surprised how often this happens, every day, and no one notices. It is all part of the intricate operation of large electric grids, which revolves around the benefits of the combination of a) massive rotating generators and b) reserve capacity of running generators.
Renewable Sources Of Electricity
Let us look at other forms of generation, like wind and solar. Those are classified as renewable because the sources of energy, wind and sun light, are not depleted.
Wind Power
In the wind option, a large fan is positioned so that the force of the wind rotates its long blades. Some blades can reach 300 ft from the hub to the tip (80 meters or more). When the wind rotates the blades, the fan-like device acts as a turbine. By connecting an electric generator to the shaft, electricity is produced.
Solar Power
In solar power systems, the sun light triggers a reaction in solar panels, which produces electricity within the panels. The form of electricity of solar panels is Direct Current (DC), making it necessary to convert it to AC through a Power Converter. Only then the power from solar panels can flow from the converter to the grid.
Installed Capacity Versus Actual Production
It has become common for power authorities to post certain “percentage” of their generation as renewable. What that number equals is the power capacity of the renewable generation as percentage of the total installed capacity of generation on the system. These are installed capacity figures and, as we shall see, they do not mean actual production of electric energy by renewable sources, namely wind and solar.
What is the Difference Between Power and Energy?
The word “Watt” is a unit of power, meaning the rate at which a generator produces energy. The actual energy that the generator produces is a different matter. When the power is constant, Energy equals the power, in watts, multiplied by the time during which the generator continuously produces such power. The preferred unit of time in this case is the hour. As a result, the unit of electric Energy becomes a Watt-hour. The kilo Watt hour (kWh), which is 1000 Watt-hour is more common. This is just information, there will be no test later, I promise! It gives you an idea about that mysterious kWh figure you see on your electricity bill. It shows how much energy you used.
On electric grids, the MW (Mega Watt) is the common unit of power for generator sizing and production and power flows. One MW is 1000 kW.
Now, let us consider a thermal power plant using coal or natural gas to run a 100 MW generator. When this generator runs for one full hour at a constant power of 100 MW, it produces 100 Mega-Watt-hour (MWh) of Energy. If it runs at a rate of only 50 MW of power, it produces 50 MWh of energy in one hour, although its “installed capacity” is 100 MW. The main point is, energy production depends on the actual continuous power the generator is producing and not on its installed capacity. A thermal plant of this type can run at 100 MW continuously as long as the plant operator maintains the fuel/steam supply. This is standard at thermal plants like fossil fuel plants and nuclear plants. That is, an Installed Capacity of 100 MW is always available to produce 100 MW X 24 = 2400 MWh of energy every day of the year.
Energy Production of Wind Turbines
A wind turbine site having an installed capacity of 100 MW is quite different from a thermal plant. Let us say this site has 20 wind turbines, each having a rated capacity of 5 MW. Theoretically, each turbine can produce 5×24 = 120 MWh of energy in 24 hours. However, it can only generate 5 MW continuously if the wind force is continuously equal to the design value through every hour of every day without the slightest of change. If you ever watched a wind charm, you can appreciate that the force of the wind changes several times a minute. And there is no way to control it. As a result, after accounting for the random variations in wind energy throughout the day, a 5 MW turbine is extremely unlikely to produce 5 MW continuously for 24 hours, every day. Typically, in the real world, it would produce 15% of that, on average, and 20% to 25% on a good day. As such, a wind turbine generation site can only produce, on average, ENERGY that is 20% of what its installed power capacity indicates. Energy is what counts!
In summary, here is one more crucial fact you need to know: when a power company or a state government declares 15% wind generation installed, it means the energy contribution of those wind sources to the grid is about 3% of the grid energy production (20% of 15%).
Energy Production of Solar Panels
In the case of solar power, the same principles apply. Firstly, energy production is cut by about half because at night the power output is Zero. So a 100 MW site can produce a maximum of about 100×12 MWh for the 12 hours of sunlight, that is 50% of theoretical energy capacity. When combined with random variations in sun light intensity throughout those daylight hours, and from day to day, the 50% figure is further reduced to not much more than 10%. In other words, if your power company says there is 5% solar capacity on the grid, the energy production of those solar sources would be about 10% of 5%, or 0.5% of the total energy production on the grid.
Limitations Of Wind And Solar Power
1. Lack of Momentum
Since the wind speed and pressure vary, the driving energy of a wind turbine changes all the time. As a result, the produced electricity continuously changes. Producers must use additional devices to condition the power output of the wind generator to make it suitable for passing on to the grid. The most common method is to use an Electronic Power converter, which receives the unsteady power from the wind turbine and converts it to useable power at 50 or 60 Hz, then feeds it into the grid. So, although the wind turbine has a significant rotating mass, its power feed into the grid comes from a static device with zero momentum. A wind turbine does not provide any momentum support to the grid. If we go back to the bike example, imagine if the rider and bike have zero momentum. If the rider stops pedalling, the bike stops instantly and its light goes off until the rider starts to pedal again. This is a very important Fact that anyone keen on renewable energy MUST UNDERSTAND. Electric power from a wind turbine comes through a static device and supplies zero momentum support to the continuity of electric supply on the grid.
As for solar power, obviously it has no momentum because there are no moving parts.
2. Variability of Power Contribution
A wind turbine generator receives its energy from the prevailing wind, which is variable and uncontrollable. Consequently, wind generation contribution to the grid is constantly changing up and down, often in very large swings, because of wind variability throughout the grid area. This forces power utilities to run other generators from conventional sources, all the time, to compensate for the swings in wind power contributions. Only fossil fuel and nuclear plants have the capacity and technical feasibility to regularly adjust their output and compensate for the variability in wind generation. Hydro plants have limits on how much they can change their output on short notice due to water management issues.
Power generation by Solar panels changes continuously. Cloud cover is a big factor. And, of course they stop altogether at night. As with wind power, solar power requires operation of conventional thermal plants to compensate for the regular swings in solar power generation.
Example: A wind power site with installed capacity of 100 MW (Megawatt) can produce between 0 and 100 MW depending on wind conditions. The grid authority must run a thermal generator that may be powered by coal, natural gas or nuclear power that has the ability to produce an extra 100 MW instantly. Let us say the thermal unit normally produces 300 MW as its base load. If the wind power source produces only 50 out of its assigned 100 MW, the thermal unit must up its output to 350 MW immediately. If the wind power goes down to 10 MW, the thermal unit changes its output immediately to 390 MW to compensate for the variation in wind power generation. This process happens continuously because wind generation is impossible to set at a constant value. As you can see, the fossil fuel generator must remain on line to adjust for the variability in wind power contribution to the grid. The same applies to solar generation.
Wind and solar sources do not keep fossil fuel units off line. Instead, they rely on them for support. And furthermore, they force the fossil fuel plants to cycle up and down all the time resulting in less than optimal efficiency.
3. No Reserve Capacity
A major limiting factor is, a wind turbine-generator has no power reserve because its energy is limited by what the wind can provide at any instant. In effect, it is always running at its maximum capacity and cannot respond to any increase in demand on the grid no matter how small the increase is.
Similarly, solar power installations do not have reserve energy to supply to the grid because their energy intake is impossible to control. No one can increase the solar energy falling onto the solar panels.
Because of this, non-renewable sources of electricity, mostly fossil fuel plants, must do ALL generation adjustments on the grid to meet fluctuations in demand, on a minute by minute basis.
Why An All Wind/Solar Network Can’t Work
Due to the limitations of wind and solar generation, the proportion of wind and solar power on a grid must be limited to a small fraction. Some grids in Europe have reached 10% installed capacity renewable but they are not very large. It is not clear if a higher percentage will ever become sustainable without excessive running of fossil fuel plants in support. Please note that “installed” capacity of renewables does NOT translate to actual energy contribution! If you can, contact your power company and ask them to give you a written statement of installed power capacity of renewables in percentage of total on their grid AND actual percentage of energy production by renewables. Don’t believe verbal assurances or brochure material.
A grid made of 100% wind and solar generators would fail to remain intact for more than a few seconds. Here is why. Remember that demand on any grid changes constantly, on a second by second basis, as consumers switch things on and off, either manually or automatically. Just think how often you change the amount of electricity you use at home by turning lights and appliances on and off. The instant demand for power increases, even slightly, neither wind turbines nor solar panels can increase their output to meet the extra demand. And they have no momentum energy to keep the lights on, so to speak. As wind turbines become overloaded, they start to get tripped off the grid because of overload, causing more overload on the remaining ones and on whatever solar panels are on. A chain reaction of successive shutdowns due to overload is triggered; with the result being fast and imminent blackout in a matter of seconds. Obviously, no industry, and indeed no society, can function this way. This is a fact and a paradox which is never explained to the general public by renewable energy advocates. Large proportion of wind and/or solar generation on a grid is not workable. It is simply impossible.
What The Power Companies Are Doing About It
Electric utilities in many parts of the world declare significant portions of their generation to be wind or solar. What they don’t publicise is that they must continue to run conventional generators, mostly fossil and nuclear, as if the wind and solar generation is not on the grid. They have no other technical solutions because there are none! They may go as far as to depend on a neighboring country for that traditional generation backup! Electricity does not recognize national boundaries. It all results in complex rate schemes designed to hide the true environmental and financial burdens of connecting those “renewables” to the grid. The burden includes the absolute necessity to run conventional units as reserve to wind and solar generation with all the associated “Carbon Emissions” from those sources. It amounts to a bizarre form of hypocrisy. The ultimate price is very high electricity cost to consumers and astronomical profits for grid operators and wind and solar producers, with negligible reduction in fossil fuel consumption and emissions.
The Bizarre Facts And Real Cost of Renewables
Perhaps now one can see why honest scientists and engineers face the daunting task of explaining the limitations of wind and solar power to the public. For every unit of power generated by wind or solar, there has to be a readily available substitute from conventional sources that is deployable in a matter of seconds, not minutes. Coal, gas fired and nuclear plants are best suited for that. And there is a reason for it. At those plants, conventional steam turbines are fed by a reservoir of steam that is always ready to supply more steam in a fraction of a second. This allows the generators to produce more electric power instantly.
The irony is, a wind or solar power producer sells power to the grid and receives premium incentive payment for it (by law) from grid authorities. At the same time, a coal or gas plant operator receives payment from the same grid authorities to have their coal-fired boilers and steam turbines make up for the fluctuations in the wind and solar generation. It goes on all the time. This is only one of the bizarre facts that you will never see on the evening news. You are more likely to see a politician make a promise to convert all electricity to wind and solar by such and such date. He or she gets the votes, you get the bill for the renewable incentives PLUS the hidden cost of running the coal/gas/nuclear plants to handle the wind and solar variability. And most sadly, there is no “green advantage” in the whole process.
The Curtailment Scheme
In some areas, electric utilities pay customers a fee to go on “curtailment standby”. In theory, the plan allows the utility to cut off their power in case the wind or solar generators fall short. And in return, the utility pays them cash. Some of the customers who go on the list end up getting their power for free all the time. You wonder why does a utility do that? Well, it allows it to publicly “declare” a significant part of its generation as renewable. But in reality they must continue to run other generators for all the reasons we discussed so far. A curtailment standby plan works only in theory and has NEVER been exercised, at least until the date of this article! The reason is, the hardware and intelligence required to execute such scheme with precision is extremely complex involving a high risk of interrupting customers who are NOT on curtailment standby. And it does not stop the need to run non-renewable plants to cover for the variability of the output of renewables. In essence, it is only a Public Relations tool. If you wonder why your electricity bill is always rising, it is to pay for all those exotic schemes that do not decrease emissions one bit.
So, Are Renewables a Bad Thing?
Not at all. Renewable sources of energy such as wind, solar, tidal, geothermal , etc. are all legitimate ways of harnessing natural renewable sources for electricity generation. But they aught not to be used as political or ideological banners without adequate consideration of their severe physical limitations and economic feasibility.
A solar panel on top of a boat is a brilliant idea. It can charge the boat battery and operate many small instruments onboard. But to replace the engine of the same boat with solar powered electric drive would be insane. The boat has to go around everywhere trolling behind it a solar array the size of two football fields. On top of that, it needs a battery weighing 1000 pounds to store energy for use at night. And if that is not enough, if the battery ever goes dead at night, the boat becomes totally powerless in the middle of the sea.
There is a clear dividing line between environmental slogans and what is physically feasible.
What is Efficiency?
We need to talk about Efficiency because we want to determine whether an electric car uses less, or more, energy than a gasoline powered car.
The term “Efficiency” defines how much of the energy needed to do something is used for the purpose; and how much is wasted (lost) in the process. For example, think of heating water in a pot on a gas stove. Basically, the gas flame heats the pot, which heats the water. Efficiency of this process is the ratio of the heat absorbed by the water to the total heat produced by the flame. This ratio will always be less than 1. The difference between the flame heat and heat retained by the water is called “losses”. In this case, the losses include energy used to heat the burner and griddle and the air around the burner, plus the energy retained by the pot itself. Only energy which is absorbed by the water is useful. The rest are losses in the process. It may surprise you, but losses can be substantial and may be over 50%. Let us say the water in the pot absorbed 40% of the energy of the flame. It means an efficiency of 40% and 60% “losses”.
More Steps in the Process Mean Less Efficiency
An interesting rule about efficiency is that, by virtue of its definition, it is a cumulative effect. To demonstrate this fact, let us pursue the same water heating example and say we want to use the hot water from that pot to warm a glass bowl. If the bowl absorbs only 50% of the heat in the water, how much of the original energy in the gas flame ends up warming the bowl?
Efficiency of water heating by the flame was 40%
Efficiency of bowl heating by the water is 50%
Efficiency of bowl heating by the flame is 50% x 40% = 20%
In other words, because of the extra step in the transfer of energy, only 20% of the heat energy produced by the flame reaches the bowl.
Summary: The more stages we introduce in the delivery of energy, the HIGHER the losses will be, and the lower the efficiency. To compensate for lower efficiency, we need more energy from the source to achieve the same thing. A car needing a tune up runs at lower efficiency than when it is properly tuned and uses more gas per mile. A tune up simply raises the efficiency.
The Electric Car Versus Gas Powered Car Dilemma
My apologies for taking you on that detour into the subject of electricity, where in fact you wanted to hear more about electric cars. But how can we even begin to form an opinion on electric vehicles without understanding the true nature of electricity. The perception that electricity is something that simply comes out of a power outlet like magic is hardly a sensible start for anything, let alone making a decision on buying a vehicle that runs on electricity.
An electric car has many of the same parts as a traditional, gasoline powered car. The main difference is that instead of a gasoline engine and a transmission, an electric vehicle has an electric motor (powered by the battery) and a transmission. In a traditional gas-powered car, a 12 Volt battery is used to start the gas (or diesel) engine. In an electric car, the battery is quite different and much bigger. It consists of several lithium-Ion batteries (about 100 of them) grouped together to produce about 400 Volts. The battery assembly sits underneath the floor of the car, occupying most of the space under the chassis, lifting the car higher and giving the electric car its awkward higher stance relative to a gas powered car. A typical battery assembly weighs 1,000 to 2,500 pounds approximately, depending on the model and size of the vehicle. Because of that, a mid size electric car weighs significantly more than a similar size gas powered car. If a mid size gas powered sedan weighs 2,500 pounds, the equivalent electric one would weigh about 3,500 pounds, that is 40% more.
The amount of energy needed to move an object is directly proportional to its weight. It follows that the average electric car uses 40% more energy to travel the same distance as a similar-size gasoline powered car. And this is due to its heavier weight only. On top of that, an electric sedan, being higher than a similar-size gas powered sedan, must push more air as it moves. Overcoming air resistance by a moving car is where most of the fuel energy is spent. This is another reason the energy an electric sedan uses to travel a certain distance is higher than what the gas powered sedan uses for the same distance. In essence, the electric sedan is typically higher and heavier than a similar size gas-powered sedan, requiring a substantially higher amount of energy to move it the same distance. Something to remember!
Which Is More Efficient, Gas Or Electric?
In a gasoline powered car, as you drive the car, the gasoline is burned and the heat energy is converted into motion, all onboard the car. Of course, there are “losses” as we discussed in the efficiency concept earlier. On average, the gasoline engine efficiency is about 30%, meaning only 30% of the heat energy in the gas shows up at the wheels. The rest is lost in various parts. The emissions from the gasoline engine obviously escape in the vicinity surrounding the car.
The source of energy onboard an electric car is the energy stored in its battery. But the energy stored in the battery comes from a power plant far away. Let us say it was a natural gas (Green) plant where electricity is generated using a gas turbine to drive the generator. The generator has to be connected to a transformer to raise the voltage and connect it to the high voltage power lines. The lines carry the electricity to your general area. Then a series of transformers bring the voltage down to the distribution lines. More transformers bring the voltage down to the level suitable for the electric car charger. Every one of those steps has an efficiency, whereby the output energy is slightly less than the input as we discussed under the subject of efficiency. We can thus track the flow of energy from the electric power plant to your car wheels as follows.
Gas turbine efficiency at the power plant, on average is 35%
Generator efficiency is 98%
Efficiency of the transformer between the generator and the high voltage grid is 98%
High voltage grid lines efficiency is 99%
Step down transformers, near you, efficiency is 98%
Local Utility low voltage distribution network efficiency is 95%
Battery charger efficiency is 90%
Efficiency of motor drive train onboard the electric car is 95%
Overall efficiency, from the natural gas burning at the power plant to the wheels of the electric vehicle = the product of all the intermediate efficiencies above, or
0.35 x 0.98 x 0.98 x 0.99 x 0.98 x 0.95 x 0.90 x 0.95 = 0.2679, that is, 27%
That is, the amount of energy reaching the wheels of the electric car is about 27% of the energy produced at the power plant in this case.
The numbers I used for efficiencies are fairly typical and the result is not surprising. It shows that the electric car wheels may receive only 27% of the original thermal energy produced at the power plant. The gasoline car’s efficiency is not much better, where the wheels may receive only 30% of the thermal energy produced by burning the fuel onboard. BUT, the electric car being 40% heavier due to the additional weight of its battery, uses 40% more energy to travel the same distance. For every mile it travels, it uses about 40% more fuel energy than what a gasoline car uses to travel one mile. And that is before accounting for the additional air resistance due to the extra height of the electric vehicle.
Is The Electric Car a Fuel Hog?
To illustrate the point, we used a specific case of a gas turbine source of electricity, which is considered the “greenest” fossil fuel option. Using typical efficiency values, we saw that the amount of energy required at the power plant to drive an electric vehicle one mile can be 1.4 times the energy used to drive a similar-size gasoline car one mile. This is due to its heavier weight and before accounting for its higher stance. However, not all power is generated by gas turbines at 35% efficiency all the time and not every gasoline engine runs at 30% efficiency all the time. There are variations in either direction. For example, steam turbine systems are less efficient than gas turbines, which would make the factor more than 1.4. On the other hand, a gas powered car can run at less than 30% efficiency, which would make the factor less than 1.4. It would be realistic, and more objective, to use a range of 1.25 to 1.5 instead of a fixed figure of 1.4. This way we can indirectly account for the higher stance of the electric vehicle without overcomplicating matters. It is bad enough I had to use many numbers. But it is an absolute necessity for you as a reader to see the true physical phenomena we are dealing with, something you would never see on CNN or Fox News.
To summarize, an electric car can use 25-50% more fuel energy to go the same distance as a similar-size gasoline powered car. This may be a surprise to many. But it is nonetheless a scientific fact that is well known among engineers and other technical specialists. A fact which doesn’t get publicized due to the heavy lobbying by business interests and ideological spin by the media in favor of electric vehicles.
By now you must have seen the (tongue-in-cheek) images of a stalled electric car being charged by a mobile gas-powered generator. Joking aside, have you ever thought of this: instead of burning the gasoline in the engine that drives the generator which charges the battery of the electric car, why not put the same amount of gasoline in a gas powered car and drive away. Without any rocket science, the gas powered car would go farther on the same amount of gasoline used to charge the battery than the electric car would go when it is recharged. Simply put, it would be a more efficient way of using that gasoline.
Finally, The Answers to Those Electric Car Questions!
We started our discussion about electric cars with a few intriguing questions. In search for answers, it was essential to take a look at Electricity, the energy that fuels electric cars. Now, let us go back and use what we know about electricity to find the correct and scientifically objective answers to those questions.
Question: Is an electric car emission free?
Answer: No. An electric car consumes 25% to 50% more energy from the prime source of energy than an equivalent size gasoline car. Energy to run the electric car must be generated at a distant power plant using, most likely, fossil fuel or nuclear reaction. With the severe limitations being put on nuclear power expansion, electric cars will only increase the demand on fossil fuel plants and, ironically, increase emissions. The only difference is that the emissions caused by electric cars are shifted away from the vicinity of the car to a remote power plant.
Question: If we increase renewable power generation like wind and solar, can that offset the increased emissions required to generate power for electric cars?
Answer: No. Wind and solar generation cannot exceed a small proportion of electricity generation on the grid because of certain physical limits (variability, lack of reserve and lack of momentum as discussed earlier). Electricity for electric cars will always have to come, mostly, from traditional forms such as coal, natural gas, nuclear and hydro generation. Hydro power is limited world-wide. It also requires massive infrastructures, disturbing natural habitat of both wildlife and humans. So, electric cars will always get the vast majority of their power from traditional power generation sources such as fossil fuel and nuclear.
Question: What happens When I Plug in my Electric Car to Charge it?
Answer: At any given time, all renewables on the grid are already at their maximum capacity and cannot increase their generation, as we explained earlier. Hence, the instant you plug in your electric vehicle, a fossil fuel generator somewhere on the grid must increase its output to feed your car battery. Neither wind nor solar sources on the grid have any reserve capacity to do that, not even to charge a single car. So, here is your bit of shocking news: every time you plug in your electric car, your battery will only be charged by 100% non-renewable generation, most of which is either from fossil fuel or nuclear powered. Make no mistake about this, the energy moving your electric car does NOT come from renewable sources of electricity. It will never do.
This leads to one disappointing, and 100% factual, conclusion. The pride one feels when she/he plugs in their car, thinking they are “saving the environment” is based on an entirely false perception. While it is by no means the EV owner’s fault, such pride is only a delusion induced by relentless misinformation by the ideologically blinded media and those who benefit tremendously from the sales of electric vehicles. We want you to know that BEFORE you buy one. And, in case you are wondering, I have absolutely nothing to loose if everyone bought an electric car and nothing to gain if everyone used gasoline cars. It is only about facts.
Question: How about those electric vehicles advertising 600 or 700 km range?
Answer: This is yet another slick entrapment of unsuspecting consumers.
Weight of the electric vehicle and capacity of its battery determine the range. The heavier the car the more energy it uses to move one mile, and hence the lower the range will be. Manufacturers already make the vehicle as light as possible. This leaves battery capacity as an option to increase the range. It is easy to increase battery capacity by adding more cells. This in turn increases the weight of the vehicle!
So here is what happens.
Please remember, until all generation world wide is from nuclear or hydro sources, electricity for electric cars will come from burning fossil fuels.
A gas powered car A use 10 liters per 100 km (about 24 miles per gallon, mpg)
A similar size electric car B, with standard battery size and 300km range, weighs 30% more. Its energy consumption is thus 30% higher than car A, equaling 13 liters/100km. This is about 18 mpg.
A similar size electric vehicle C, with twice the battery weight and 600km range, weighs 60% more than car A. Its energy consumption is 60% higher, giving an equivalent rating of 16 liter per 100km. This is about 15 mpg.
So, here you have it:
Gasoline mid size vehicle A, mileage is 10 liter/100km (24 mpg). Emissions 100 units.
Electric mid size vehicle B, normal range 300km, mileage based on source fuel consumption is 13 liter/100km (18 mpg). Emissions 130 units.
Electric vehicle C, long range 600km, mileage based on source fuel consumption is 16 liter/100km (15 mpg). Emissions 160 units.
Which car would you rather drive?
Question: Should you get an electric vehicle?
Answer: No. This is evident from the science we covered so far. You would be increasing the demand for expanding traditional power generation and particularly fossil fuel and nuclear sources. Not only that, but you would be wasting more energy than if you drove a gas powered car. Imagine your friend’s travelling 100 km in their gas car, burning 10 liters of gasoline. When you drive your electric car for a 100 km, someone at a distant power plant had to burn the equivalent of 12.5 to 15 liters of gasoline to move your electric car those 100 km. You also subject yourself to all the cliché (but true) downsides of electric cars, such as limited range of travel, scarcity of charging stations, outrageous cost of battery replacement, and the horrendous mining snowball effects to produce the minerals for those batteries, just to name a few.
Keep this in mind: Your electric car uses more fuel energy, 25 to 50% more, than a similar size gasoline car; and most of this energy comes from burning fossil fuels. Please think about that before you get an electric car.
Question: Can I Charge an Electric Vehicle at home?
Answer: Maybe! Manufacturers of electric cars proclaim it takes 6 to 7 hours to charge the battery at home. However, the normal household outlet in North America can supply a maximum of about 1.8 units of energy in one hour, that is 1.8 kilo-watt-hour (kwh). It is simply the product of the capacity of the outlet of 15 Amperes by 120 Volts. Breakers in your panel at home would trip if the power drawn from the outlet exceeds that (15 Amperes at 120V). The battery of one of the popular electric cars on the market today needs 60 kwh to reach full charge. You do the math! Considering the charger efficiency is 90%, it would take about 37 hours to deliver 60 kwh to your car battery from a standard 15 A, 120 V outlet at home (North America). Alternately, you can make significant and costly wiring changes in your home to add an outlet big enough to charge the car in less time.
Question: What is a Hybrid vehicle?
Answer: A hybrid vehicle is a high efficiency gasoline-powered vehicle. It uses a battery to achieve its high efficiency by saving and reusing some of the energy lost during driving. As the car coasts or goes downhill, the battery is charged by the momentum of the car (Oh, that magic momentum!!). The stored energy in the battery is reused when needed to reduce the demand on the gas engine. It all adds up to very substantial savings (up to 50%) in gas consumption. A hybrid is a much better choice than an electric vehicle, both from economical and environmental perspectives. It is a superior option that has become a victim of ideological obsession with electric cars.
Question: Do I have to charge a hybrid vehicle?
Answer: No, for a pure/simple hybrid. A hybrid runs on gasoline only and does not use external charging. However, you may encounter what is called a “Plug In Hybrid” which requires regular plug in to enhance its fuel consumption. Skip the plug in hybrid. Stick to simple Hybrid with no plug in.
Summary
We hope you gained some insight in the subject of electric cars. Electric cars were produced decades ago and found to be impractical. Unfortunately, the hysteria about fossil fuels, global warming and climate change made our society lose all reasoning. Electric vehicles do not lessen the need for, or consumption of, fossil fuels. To the contrary, they amplify those needs. An electric vehicle is nothing more than a novelty that does not make any sense. It is not only a white elephant, it is a hungry white elephant with worms in its guts.
The general public sees a car without a gas engine or emissions. The truth is, somewhere in the distance, someone is burning fuel to generate electricity for this car. The car may appear benign and better for the environment, but the fuel being burned at the plant, most likely, is just as problematic as the fuel in the tank of a gasoline powered car. And ironically, it takes more fuel energy at the power plant to make the electric car go a mile than the gasoline energy it takes to make a traditional car go a mile.
Wind and solar power are intermittent and problematic and cannot scratch the surface of the energy demands of the world. They are impossible dreams, hyped up by uninformed, and often biased, media and pseudo scientists. The public is kept in the dark about the severe limitations of wind and solar renewables. No one knows that it is impossible to have more than a small proportion of renewables on the grid, without jeopardizing its reliability; and at an obscene cost. Such is the tragic outcome of junk science gone mad in this world we live in.
