1. Why did you choose the subtitle 'Energy supply is more important than climate change'? Don't you find it a bit controversial?

Answer: Yes. 'Energy supply is more important than climate change' is far more controversial a title than I ever imagined. By no means do I wish to disparage the importance of climate change issues. Climate change and global warming are very important issues! However, as I have watched the debate grow over the past several years, it is clear that most people have no idea how much energy our society consumes, nor how important it is to Humankind and the adaptation to climate change.

One of the points I am trying to make with Nobody's Fuel is that we have become such a wealthy society - thanks to the consumption of fossil fuels - that we can afford such a civilized public debate. The signs on the wall all point to a time, perhaps within a generation, when affordable, high quality energy may begin to become scarce.

2. I am curious why geothermal was given such a passing reference in your presentation.  I have often wondered how a planet which is essentially a thin organic mantle floating on a giant ball of molten iron can have energy issues.

Answer: Geothermal in Nobody’s Fuel refers to volcanic geothermal, which is what you appear to be referring to. The centre of the earth is kept warm by radioactive decay. The mantle you refer to is not organic, but a a mix of minerals which we call rock. As one goes deeper into the mantle, the temperature increases.

The temperature is 1300 degrees Celcius at the base of the lithosphere, which is a few kilometers thick in ocean spreading areas, 100-150 km thick under parts of the ocean basins and up to 250-300 km thick under continental shield areas. The higher the temperature source the more useful and valuable it is. Thus, useful temperatures are a long way down into the earth.

The next important point about energy is the supply. The amount of energy that can be taken out of a specific “bore hole” area depends on the rate at which replacement energy can be conducted through the surrounding rock. Rock is not a good conductor of heat for this purpose. The rate at which energy can be produced is very small. People are proposing to fracture the rock and force water between to bore holes some distance apart. Again, the rate of energy output depends on the relatively poor conductivity of the rock in this application.

In other words, there may be lots heat energy in the core of the earth many km deep, but the rate of production of energy is small. Where the earth itself has “hot spots” that generate steam, there are useful supplies of energy for a local area.

3. I have heard of people in North America building geothermal energy into their own homes. How is this possible?

Answer: What is most often referred to academically as geothermal energy is specifically volcanic geothermal, such as that found in Iceland. The other form commonly known as geothermal is really a marketing term; it is really a ground source heat pump. Usually pipes are sunk deep into the ground below a dwelling and heat can be circulated from below to help heat or aircondition the home. However, the temperature difference between the ground and surface contains very little energy. It may be true that some heat saving is realized by the homeowner. But there is nowhere near enough energy to generate steam and create electricity.