By Alex Serpo

Alex likes to listen to shells because they sing the song of the sea. He is interested in the bit of science between chemistry and biology.

As I write this, it seems the world is in a bit of a pickle. Greenhouse gas concentrations are rapidly rising and it’s thought if they cross some hidden threshold we will no long be able to stop ‘runaway’ climate change.

This means we need a simple solution to a complex problem – and fast. Experts say if we are going to solve the problem, we are going to need a mixture of different renewable energy sources. Options include: wind, solar, biofuels, geothermal, wave and tide.

Of all the renewables listed above, one stands as different. Did you say biofuels? Well you’d be right.

Why? Because biofuel is the only renewable energy source listed that isn’t a direct source of electricity. Now, before you jump up and down about rising food prices and destruction of rainforest to grow palm oil, let’s take a closer look at the black sheep of renewable energy.

For any renewable energy source to be truly successful, it has to be cheaper or close in price to oil, gas or coal. It also has to be just as versatile. In other words, we have to be able to harness energy from this source as easily as we can dig pollution-spewing hydrocarbons out of the ground.

Herein lies the problem. Natural hydrocarbons aren’t very hard to dig up.

They are also extremely easy to store and transport. The final point is the real kicker – they are extremely energy rich. Let’s take a simple example: the humble 70 litre tank of liquid octane hydrocarbon you might buy from your local service station.

To store the same amount of energy in lithium ion polymer batteries you need a battery pack weighing about 120kgs (working with 48,000 kj/kg octane versus 28,000 kj/kg lithium ion, rough but accurate). So, not only will chemical energy take your car further than electrical energy, but a 70L steel tank is a whole lot easier to manufacture than 120kgs of batteries.

So you don’t need to watch conspiracy documentaries on what or ‘Who Killed the Electric Car‘.

(but if you want to watch this trailer, go right ahead. -ed.)

The metric you just read killed the electric car – and continues to mean that for the transport industry, hydrocarbons are king. Don’t forget that along with the batteries in your car; you also need them in roadside recharge stations and possibly even attached to the grid to support variable energy sources like solar and wind.

The other problem with electricity is our tendency to lose it.

That is, whenever electricity is transported over a considerable distance, the electrical wires get hot and energy is lost. This energy loss is considerable and has been estimated to be between seven and eight percent in modern grids. Any subsequent conversion confers more energy loss – AC to DC, high voltage to low voltage, high current to low current. As a net effect, you can easily lose most of the energy you produced before it does any useful work.

Enter the black sheep. Biofuels are easy to store. Just put them in barrels, and ship them anywhere without any loss of energy. They can also be kept almost indefinitely, whereas batteries have to be replaced after a number of cycles. Finally, in many ways biofuels are also great deal safer than electrical systems. What starts more fires, petrol tanks or electrical wires?

At this point you may be asking: “Don’t biofuels produce air pollution just like fossil fuels?” The answer is yes and no. Because biofuels come from plants, their carbon and nitrogen content has already been ‘fixed’ from the atmosphere. So they aren’t adding more of anything to the atmosphere. It’s nature’s way of recycling.

But wait! There’s more good news. If you combine biofuels with some kind of (currently hypothetical) carbon capture technology, by burning them you can actually reduce the volume of atmospheric pollutants.

Five common biofuels are:

-Biodiesel
-Ethanol
-Methanol
-Organic hydrogen
-Methane

Of these biofuels there is one that stands out from all others. It’s the light alcohol called ethanol. While you’re probably used to drinking it, you may not know that Henry Ford intended his first Model T car to run on it. In fact, most modern cars can be easily covered to run on 100% ethanol. In one of the world’s largest car manufacturing nations – Brazil – many cars, trucks and buses already do. This means we can keep our entire existing transport infrastructure.

So why ethanol? Why not biodiesel? Or methanol, butanol, biological hydrogen or any other of the vast array of biofuels? The answer is that ethanol is the easiest thing for microbes to make out of cellulose. Cellulose makes up most of all plant life and is the most abundant biological material on earth.

The fact that cellulose comes from living organisms and can be converted to ethanol via living organisms is extremely important. Why? Solar panels and wind turbines don’t manufacture themselves. I make this point because sources of cellulose do manufacture themselves. They grow and breed with just a little water and some sunshine. Industry is currently deriving cellulose from the husks of wheat, rice and corn, as well as cellulose specific crops like switch grass. You can even make it from recycled cardboard.

When it comes to climate change, the real challenge is to find an energy source that can economically compete with oil and coal. Now the underlying reason why fossil fuels are so cheap is because in the distant past they were produced by photosynthesis. This amazing biological reaction is far more efficient and vast than any industrial process accessible to modern society. To date, no man-made technology can compete with this amazing natural process.

That means there is only one way to beat nature at its own game. The only way to beat naturally produced fuels is with naturally produced fuels. If we’re going to beat climate change, we need to fight fire with fire.

Below are some Climate Change related events taking place during National Science Week. Check out the events calendar for more.

August 20th

Climate change videoconferences (ongoing)

Wetlands and climate change

August 21st

Café Scientifque – Climate Change: Global Warning (ACT)

August 27th

What will our coral reefs look like in 2050?

Tags: biofuels, Climate Change, ethanol

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