Portable Energy

The expansion of civilization has been a function of access to portable energy. With the ability to capture the power of wind through development of sails civilisation expanded, but primarily over water where this "free" energy could be taken advantage of. On land for centuries the form of portable energy that was commonly used was wood. The problem with wood is that it does not have a very high energy density ( 2.5 - 4.4 kWh/Kg) so it takes a lot of wood to get a reasonable amount of energy. Another problem was the cost of transforming that wood into a form that made it relatively easy to move around with you at reasonable cost.

Fuel	Thermal Energy
	(Calorific Content)
	kWh/Kg
Green Wood	2.5
Brown Coal (Lignite)	2.8
Dry Wood	4.4
Methanol	6.4
Coking (Black) Coal	8.3
Ethanol	8.3
Natural Gas (North Sea)	10.8
Bio diesel	10.9
Oil	12.5
Diesel	12.9
Kerosene (Paraffin Oil)	13
Petrol (Gasoline)	13
Butane	13.7
Liquefied Petroleum Gas (LPG) is a mixture of Propane and Butane	13.8
Propane	13.9
Uranium 235 (Nuclear Fission)	22,500,000
Deuterium - Tritium (40 / 60) (Nuclear Fusion)	93,600,000
adapted from http://www.mpoweruk.com/energy_resources.htm

In some locations a black rock called coal was found that, like wood, would burn thus releasing its contained energy. Unlike wood it contains a higher energy density (8.3 kWh/Kg)  and when crushed is easier to transport. Over time methods were found to mine coal thus making its availability much easier and through the economies of scale the cost per unit was brought down so that it was dramatically less than wood. With its wholesale introduction thus began the industrial revolution! But when it came to transportation, primarily through the introduction of the stream engine, the volume required of coal and the resultant useful energy captured did not allow much independence; it still was bulky and that could only be alleviated by setting up large caches ahead of time.

Like coal another form of energy had been known for a long time is petroleum. When the supply greatly expanded due to the discovery of a proliferation of oil fields civilisation was able to take advantage of its higher energy density than coal. Plus it had the additional advantage that it is easier to transport as no longer were we subjected to the swell factors associated with solids that need to be broken apart to make them easier to transport (typically 75-85% for coal). So not only was oil easier to acquire because being a liquid it could be pumped it also can be transported in a denser form even though the energy density is not that much higher (about 12. 5 depending on the liquid, compared to 8.3 for coal). It is this compactness, along with low cost, that once again revolutionized the economy leading to our current state. Inexpensive yet portable energy has had a dramatic positive impact on civilisation!

Where will we go from here? As you can see from the energy density table if we can master containing fission or fusion into much smaller packages who knows.

To back track, this transformation all began with a form of "free" energy - wind. Not only is it "free" for the taking, it is available just about anywhere on the earth's surface. So no need to expend money to acquire it other than the mechanics of using the kinetic energy of wind. Nor is there a need to find a way to contain it. The big problem is that wind does not always blow when you need it. Another form of "free" energy that we have access to is solar. Like wind it is a form of "kinetic" energy in that it is result of the  movement of photons. Like wind solar suffers in that this energy is only when the sun shines and not occluded by cloud cover and so is not always available when you need it.

While we cannot directly store wind and solar energy we can convert them into electrical energy which can then be stored in batteries, or used to convert that energy back into another form of kinetic energy that can be stored, such as water. The problem with batteries is how can we make them "portable" such that we can take enough energy with us to give similar levels of independence at an affordable cost that we get with petroleum? To have the capacity we need, using current technology, we have excessive weight and volume to the point the gain diminishes rapidly as too much energy is required just to move the mass of the batteries. Another change needs to be a form of standardisation in battery packs so they can be quickly swapped out thus negating the issue of requiring long time periods to charge and the ability to have multiple packs so that longer distances can be traveled, similar to having jerry cans of gasoline for an internal combustion automobile.

Even with these issues I believe we are approaching a tipping point. We currently have a multitude of means of creating electricity, and that energy can be stored and made portable, including both wind and solar. When, not if, that an affordable means of storing electricity is found civilisation will undergo another positive transformation.

Note that historically all of these advances in civilisation were the result of technological and economic breakthroughs and not by government intervention. So even though there is much government "encouragement" of electric vehicles it is a classic example of putting "the cart before the horse". When industry can come up with a way to store and transport energy in a such a way that it is useful no matter where you are in the world, night and day, just like petroleum, then we can make the next leap forward.

Will that breakthrough be with batteries? Maybe, if they can standardise on the form factor so they can be easily swapped in and out and avoid long recharging wait times; and improve the weight to contained power density; and figure out a way to solve the problem of greatly reduced battery output with decreasing temperature. Lots of issues, never mind the high cost with no means on the horizon of having a dramatic decrease any time soon.

Maybe fuel cells can solve the remaining hurdles that prevent them from being cost effective? Another possibility is that maybe someone will come up with a cost effective way of converting hydrogen and carbon into synthetic petroleum. Now wouldn't that be something! Take elements that abound in nature and combine all into a form for which we already have the infrastructure and the means of using. That would be transformational! Yes, I know, we already have ethanol and biodiesel but their cost of production is still too high based on current technology and sacrifice that land for food production. Maybe the next breakthrough will be using the high energy density of nuclear to cheaply break apart water to release hydrogen, do the same with organic compounds to release carbon and then using catalysts combine the two to make synthetic gasoline?

Regardless, researchers are looking and I am very confident a breakthrough will come long before we run out of conventional petroleum. So many possibilities but driven by the market place and not by government interference. What is that quote attributed to Reagan? Oh yeah, "The nine most terrifying words in the English language are: 'I'm from the government and I'm here to help.'"