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Renewable Energy Carriers

Updated on May 24, 2017

What will we use as fuel in the future?

As the availability of fossil fuels reduces in the future new forms of sustainable energy carriers will be needed. For over 100 years we have depended on oil and gas as fuel for our cars, ships and airplanes. In the near future we will still need those transportation methods so there is a great need to find new energy carriers which are suitable as fuel and can replace fossil fuels used in cars, ships and airplanes.

Can we stop using fossil fuels?
Can we stop using fossil fuels? | Source

There is however no real need to have only one medium, a wide variety might even serve a better purpose, allowing for a more tailored approach depending on the needs of specific industries. There are already several working ideas for suitable energy carriers to store and transport energy in either liquid form or gaseous that can be developed in a sustainable manner. These are

  • Hydrogen
  • Methane
  • Methanol
  • Ethanol
  • Biodiesel

So lets go over the pro´s and con's of these possibilities.

Hydrogen

My personal view is that hydrogen (chemical formula: H2) will become the main fuel medium of the future. The simplicity in which it can be produced from water using electricity and the great energy efficiency that has already been reached using fuel cells being the main reasons for this belief.

The main problem with hydrogen though is the difficulty with storing it. As a gas that has a boiling temperature of -253°C it is extremely hard to store in liquid form. Hydrogen in gas form also has very low energy per volume, resulting in the need for high pressure canisters should hydrogen be used as fuel. And while the canisters could be stored in a vehicle in a mostly safe manner just try to explain to your mother how driving a car with two 400 bar tanks underneath you is safe.

The hydrogen atom. Simplest of atoms.
The hydrogen atom. Simplest of atoms. | Source

Because of this problem with safety, both real and imaginary, there have been great efforts made in developing a metal hybrid mesh to store hydrogen under much less pressure. At the moment the temperatures needed for this to work are far to low for commercial use, but last I heard you could use a certain type of mesh on the south-pole with good success.

When the problem with storing it safely has been solved the rest is really easy. Hydrogen is easily produced on site by electrolysis and fuel pumps suitable for hydrogen have already been developed. Hydrogen is also a nice compound to produce using renewables like solar and wind as it can be produced when there is an energy surplus in the grid and then stored for use later on.

Methane

Methane (chemical formula : CH4) is a gas at room temperature that is commercially sourced from natural gas. Such methane is in no way different than other fossil fuels and cannot be considered a suistainable choice, although it does deliver more energy with less carbon emissions than petrol and diesel.

Methane however is also a by-product of biomass degradation, called biogas. Methane collected that way and burned as fuel can be considered to be renewable with the added bonus of reducing carbon footprint as methane is a 21 times greater greenhouse gas than carbon dioxide, meaning it is much better to burn it that release it into the atmosphere.

There are already several car companies producing commercial cars which run on either pure methane or directly on biogas. As it is already being used in a large scale to drive vehicles it is tempting to consider it as the solution to the energy carrier dillemma. The problem however lies in the fact that biogas production is a lengthy process and would require significant infrastructure changes as production areas would be scattered and not centralized like natural gas. The total amount of biogas which can be produced this way is also not enough to fuel every vehicle on earth.

Methane could however be a nice supplement to hydrogen and possibly other energy carriers as farmland and biowaste are not going away anytime soon.

Methanol

Methanol (chemical formula: CH3OH, also known as wood alcohol) is one of the liquids that have been discussed as a possible energy carrier. Methanol is a liquid at room temperature with a boiling point at 64,6°C and as such could easily be integrated into the modern fossil fuel infrastructure. It is a well known compound that has widespread industrial uses. Methanol is commercially produced to day by a process called steam reform that effectively turns methane into methanol via chemical processes.

Methanol produced from natural gas methane cannot be considered a renewable source. There are however other methods of producing it. By sourcing the methane from biomass methanol can be produced and used as fuel in a carbon neutral process.

In addition a company called Carbon Recycling International is developing a method to produce methanol directly from hydrogen and carbon dioxide using electricity from a renewable source. This technology is still in development with a test plant producing 2 million liters a year. The carbon dioxide is sourced from a local power plant and as such the methanol can be considered carbon neutral as each carbon that is released from the car would have been released anyway from the power plant itself.

Did you know that...

  • Ethanol is the substance that causes intoxication
  • Ethanol has been used for thousands of years
  • The chemical formula for ethanol is C2H5OH

Ethanol

Ethanol (chemical formula: C2H5OH), like methanol, is a liquid at room temperature with a boiling point of 79°C. Ethanol is already used in various locations around the globe as fuel. Ethanol is mainly produced from corn and sugarcane and is therefore really a renewable energy carrier.

The problem with ethanol is that a lot of farmland needs to go under crops for ethanol production, leading to increased prices of food around the world. This has already started to happen with selected food products such as rice and sugar. Do to this ethanol cannot be the main energy carrier of the future as it would have a serious effect on global food prices.

Biodiesel

Biodiesel is a common name for all fuel that is produced from organic material and changed into diesel fuel via chemical synthesis. Like ethanol, biodiesel is mainly produced from farmland produce. However it could easily be produced from other sources like algae and biowaste. With an added bonus that cars would not need to change much it has a greater potential to be an important factor in the future energy market.

Already great research is being done in biodiesel and in some locations biodiesel is being used in both cars, tractors and boats. The use is however still only a fraction of the total energy market.

Summary

These are just a few of the ideas for energy storage that have been discussed. What they all have in common is that the energy used to drive their production must also be from a renewable source. Some of them like ethanol and biodiesel have an inbuilt renewable energy source ( the sun ) which drives them.

Others like hydrogen can technically be produced from electricity which originates from fossil-fuels. This would however be a futile effort really and much better to use the fossil fuels directly. So for hydrogen and methanol to be a viable energy carrier the future energy sources would need to be from renewable energy sources.

© 2013 Levictus Marcus Saarith

Questions? Comments?

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    • mcspocky lm profile image

      mcspocky lm 4 years ago

      Excellent lens! The United States is dragging behind many other countries in the world converting to renewable energy. We need to get with it, or be left in the dust.

      "Germany has five times as much solar power as the U.S. â despite Alaska levels of sun"

      http://www.washingtonpost.com/blogs/wonkblog/wp/20...

    • profile image

      JoshK47 4 years ago

      Good info!