Favourite Scientific Subject - Today's Topic: Energy

[diebitter]

This is an experiment (anecdotal, not scientific), where I invite the scientifically-minded to write on one of their favourite sciences or areas of study, given a subject heading. It can be long, short, or even an anecdote, I just ask it is roughly scientific or technological, is all.

The subject today is: ENERGY

Ecology is the science I wish to talk briefly about, and more specifically Ecological Energetics. I talk about the sepcifics here from quite old memory, so forgive any vagueness, please.

Ecological Energetics ( wikipedia entry (http://en.wikipedia.org/wiki/Ecological_energetics)) is the quantitative study of energy through an ecosystem. I'm not going to go into the nitty-gritty of this, but just tell you of a long-standing memory of a lecture/discussion on it that made a big impression on me, and made me realise more deeply the intricacies that spring from the simple mechanism of evolution by natural selection.

A dragonfly larvae feeding on a specific prey (let's say water fleas) does not eat the whole thing (there are few predatory animals that consume their prey entirely, though it does happen). They eat parts. At what point do they stop? Do they eat everything possibly edible by their mouthparts, or do they leave some? If so, why?

Study shows they do in fact lave edible parts, and the amount left relates to how easy it is to capture the prey. The easier it is, the more they leave on any one captured prey. Why? Because some parts are more nutritious than others. It can be seen that, when plentiful prey are about, the dragonfly larvae will often only eat select parts of the prey before catching the next one. Why? Because, simply put, its balance of energy derived is greater. The overall intake of energy for the larvae is greater if it eats these select parts and moves to the next prey, than if it eats as much as possible from the original prey.

Not only is this the case, but studies have shown that this is almost perfectly balanced. These simple creatures disengage from eating prey to catch the next one at the point their energy balance peaks.

How can simple creatures do this? From millions of years of evolutionary pressure, it seems...the indivudals that happened to feed this way to maximise their energy intake tended to have more offspring going to the next generation.

Beautiful, isn't it?



I'm sorry, I can't remember the source, can't cite any specific documents on this, but I do remember being deeply impressed by this, and have never forgotten it.


I would like to hear more about Energy and other Scientific or technological subjects. Please proceed.

[purnell]

As for the topic of energy, I think the most important question is "Where will it come from?" That is, since it seems pretty clear that oil and natural gas will lose their economic viability in the fairly near future, how are we going to power the world's economy? It seems clear to me that nuclear fission will take on a much larger role, and there is still alot of coal in the ground, but using it without destroying the environment will be difficult. There is quite alot of (irrational?) resistance to nuclear power at the moment. What can be done to overcome that?

Research into solar electricity generation continues, but it appears that it will not be economically feasible on a large scale for quite a while.

Are there any other promising solutions?

Edited to change "fusion" to "fission". Doh.

[guesswest]

purn - I think the sad truth is that this issue will be resolved almost exclusively by the political and commercial lobbying weight of the respective energy sectors. With the scientific and ecological viability of the options available (assuming basic sustainability) being something of an afterthought.

The best solution would be micro energy supplies. With households and businesses wherever possible creating their own energy supply, whether by wind, solar etc. Still linked to a centralized energy grid, both charging for excess demand and rebating for over-production. The demand on a centralized supply would then be considerably less - allowing the possibility of much more environmentally friendly means of sourcing.

That's a wet dream though. Such a set-up would be generations away even if there was fierce government support for it's installation. And since we have the opposite, huge vested corporate and government interest in controlling power supplies, it's nowhere on the horizon.

[Pauwl]

I'll discuss oil a little bit.

Conventional oil is a very light oil that is easy to process and usually has very little sulfur content. This is what they have in places like Saudi Arabia and Texas. It is easy to produce and easy to refine into usable products such as Naptha (gasoline), Diesel, VGO, Asphalt,etc. This type of oil is the primary source of hydrocarbon energy in the world and we are eating it up like there's no tomorrow.

There is however, a different kind of oil. This is called bitumen/heavy oil. This is extremely messy oil and it's very heavy and requires a much more complicated system to upgrade and refine it into useable products. In uprading and refining bitumen you end up with huge amounts of coke, which is basically pure carbon with very little hydrogen content and can be sold for 0.05$ per 1000 kg, in other words it's useless. The difficulty in producing and processing this oil is why it has been overlooked for so long. But as conventional oil reserves get smaller and smaller, suddenly this is becoming a worthwhile energy source.

In northern Alberta (Canada), there are huge deposits of this bitumen stored in sand. These are called the Oil Sands. The oil sands projects are mining the oil stored in these huge deposits, and removing the sand, and upgrading it to synthetic crude oil (SCO). SCO is virtually the same as conventional oil and is sold to refineries in the USA.

I believe that these oil sands projects are the future of oil supply for the USA and the entire world. These projects are growing at an alarming rate. In the last 5 years, $25 billion has been put into these projects. The amount of oil that is stored in these oil sands is near 200 billion barrells (from memory). China and Saudi Arabia are already investing in these projects and billions of dollars continue to get pumped into research into improved extraction and processing methods. I'm not sure if it isn't already, but this will become the main source of oil imports for the USA in the coming years.

Anyways, I blabbed on about this, and you could probably get more accurate numbers and a better description of this from an online source. But the point I was trying to make is that Canada has a huge amount of oil stored in these oil sands. And the Oil Sands projects are growing rapidly and quickly becoming a huge source of oil for America and the rest of the world. Canada would probably be the most convenient place for the USA to find WMD's next /images/graemlins/tongue.gif.