Why electric jeeps may not be such a good idea, 2

WHAT IF the source of energy is a renewable one, such as geothermal? The heat energy from a geothermal plant cannot be directly fed into a car in order to run its wheels. It is first converted into electricity. Therefore, we have:

Heat energy released by geothermal source → mechanical energy of heated moving gas → mechanical energy of the turbine of an electric generator → electricity ( electrical energy) → chemical energy of a battery → mechanical energy that powers the wheels of an electric vehicle

How does this compare with internal combustion engine of our regular automobiles? Gasoline comes from crude oil. The oil has to be dug up, refined, sent to an electric generator. All these use more energy.

On the other hand, the geothermal plant just sits there, transforming heat from the Earth’s internal heat into electricity. Less energy is wasted.

( For those with the interest, geothermal energy is heat that ultimately comes from radioactive decay of the Earth’s primordial long-lived radionuclides, Uranium 235, Uranium 238, Thorium 232, and Potassium 40, and the planet’s ongoing contraction because of gravity ( gravitational potential energy). Both of which are produced free of charge all the time by our planet.)

In conclusion, electric jeeps and other electric vehicles may not be such a good idea in certain situations. What situations? If the source of the vehicles’ electricity are fossil fuels such as coal, oil, or natural gas. We just end up using, and wasting, more fossil fuels.

We can apply the same principle in order to evaluate a so- called hydrogen economy. May so-called environmentalists like the idea of using hydrogen as energy source instead of hydrocarbons because combusting hydrogen produces only water, while combusting hydrocarbons and coal also produces carbon dioxide.

However, generally it’s not a good idea. The devil is in the type of hydrogen.

Hydrogen as an energy source can be classified as:

Natural hydrogen (also known as white hydrogen or gold hydrogen), generated by natural process.

Green hydrogen, made from renewable energy sources.

Gray (also known as brown or black hydrogen), obtained from fossil fuels.

Suppose you have a hydrogenpowered car.

Let us start with gray hydrogen. Most of today’s commercially produced hydrogen is made by a process called steam reforming, which is also the most economical way of producing commercial hydrogen in massive amounts.

CH ( methane usually from natural gas )+ HO→ CO( carbon monoxide) + 3 H

Then you combust the H in your car, or turn it into electricity if your car has a hydrogen fuel cell ( an electrochemical cell that converts the chemical energy of the hydrogen fuel into electricity through redox reactions with oxygen as oxidizing agent). Only water is produced.

2 H+ O →2 HO

Notice that the above process involves at least two arrows. Plus, you also have to obtain the methane from natural gas sources, transport it to factories that do the steam reforming, isolate and transport the hydrogen to your car. Wasteful. The process also can’t avoid producing carbon dioxide (into which carbon monoxide is eventually oxidized to in the atmosphere) in the steam reforming process.

However, you can just combust

methane in a single process your car.

CH +2 O →2 HO+ CO

4 2 2 2 Therefore, using gray hydrogen as a fuel source is mostly a bad idea. You waste more energy, combust more fossil fuels, produce more carbon dioxide.

What about green hydrogen, made from renewable energy sources, as a source of fuel?

The most convenient way to produce green hydrogen is by electrolysis of water. It can be done anywhere there is water and electricity. However, this consumes a lot more energy than steam reforming methane into hydrogen.

2 H O → 2 H + O (lots of 2 2 2 electrical energy required)

Thus, it is practical to produce green hydrogen only if there is a readily available cheap source of electricity.