Saturday, September 02, 2006

clean energy

There are many people claiming that nuclear power will solve all the ills of the world. However this does not seem to be possible. Firstly you have to consider the hidden costs of nuclear power such as deaths from the mining industry (ingesting uranium ore is a really bad thing) and the difficulty in disposing of radioactive waste. But rather than concentrating on the bad aspects of nuclear power (which are well documented) I will concentrate on some of the viable alternatives.

Wind power is a really good option, particularly for countries such as Australia that have a low population density and a large land area. The Chinese government is investing heavily in wind power, I think it's safe to assume that it's not because they are great environmentalists but because they simply need more energy than they can get from other sources and that they have strategic reasons for not wanting to rely on Australian coal and uranium or Arabian oil. Most energy sources have some drawbacks, but wind power has no side effects and isn't going to kill birds either (birds have evolved the ability to detect and avoid predatory birds, they can easily avoid large fixed objects such as fans from wind farms).

Two other good options are wave and tidal power. These are better than river based hydro-electricity because there is no need to create dams that remove forests. Wave and tidal power are both very predictable which is an advantage when compared to wind power which is less predictable. One solution to the unpredictability of wind power is to couple it with a river based hydro-electric system which can provide electricity when there is less wind. A hydro-electric system to compensate for days that are less windy would need a much smaller dam than one that is designed to provide the main power source.

The next issue is how to power vehicles (on air, land, and sea). Advocates of nuclear power often talk about hydrogen powered cars. However while hydrogen has a good ratio of energy to weight it is not very dense, so the energy density for volume is much less than petrol. Combining Prius technology with
hydrogen in an internal combustion engine still won't give the distance per tank of fuel as petrol does. Hydrogen with fuel cells in an all electric vehicle might allow you to drive the same distance as a non-hybrid car on petrol, but probably won't compare to the range of a hybrid Diesel vehicle.

Bio-Diesel is a good option for fuelling cars. Diesel engines give greater efficiency than Otto cycle (the most common car engine) or Atkinson cycle (as used in the Prius) engines. Not only is bio-Diesel renewable but it also produces exhaust that is less toxic than that which is produced from fossil fuels. See the VeggieVan site for more details on bio-Diesel. The toxic fossil fuels are linked to health problems in airline hostesses, AFAIK there has been no research on the impact of car exhaust on pedestrians.

One thing to note about bie-Diesel is that you can do it right now. According to a British TV documentary all you have to do is filter oil that was used for frying food (they used oil from a Mexican restaurant) and mix it with a small amount of ethanol and it's ready to use in your car. As restaurants currently have to pay to dispose of old frying oil this should be good for everyone!

Bio-Diesel could work for powering planes, there is already research in progress on this issue, but there are problems related to the viscosity of bio-Diesel at low temperatures. Maybe a blend of bio-Diesel and bio-Ethanol would work. Ethanol freezes at -114.3C and should lower the freeze temperature of bio-Diesel.

Bio-Diesel would of course work really well for ships. Supplying the amount of fuel that current ships need would be difficult. Some analysis shows that the deck area of a ship can collect enough sunlight to supply ~10% of the power needs of the ship. The Orcelle is a design for a totally clean ship that runs on solar, wind, and wave power. However with the proposed design the solar panels will not be angled effectively for collecting sunlight as they will be on sails. I think that there is a lot of potential in having a design based around sails, wave and solar power for generating electricity, and also a Diesel engine running on bio-Diesel fuel for supplying extra power when required (EG when sailing at night in calm weather). Building a ship that uses only wind, solar, and wave power would probably be significantly more expensive than the current Diesel design. Building a ship that uses 10% Diesel and 90% wind, solar, and wave power might be a lot cheaper.

There are lots of ways of producing the energy we need to maintain our current standard of living. If our government was to spend as much money researching them as it does protecting petroleum reserves then the problem would be solved.


Anonymous said...

Russell your blog is always completely broken on

Is there a simple way to fix it? Since reading the entries and their markup is just too painful ..

Philipp Kern said...

Seconded. Your blog entries are always an interesting read, but it's completely broken in rss2email.

chele said...

A large chunk of our energy usage is wasted, and does not increase the quality of our lives. For example, 99% of buildings can be heated and cooled using passive methods (insulation, shading, ventilation). Such buildings actually increase the quality of life and are cheaper to use over long periods of time.

Transport conventions also cut into our quality of life. People who live in communities were walking is a viable transportation method live happier, healthier lives. For longer trips, mass transit is much more efficient then private automobiles.

Perhaps it's just a macho thing to want to maintain or increase levels of consumption, makes us feel important. Is that why energy conservation is rarely mentioned in articles about pollution or weaning ourselves from oil?

I don't understand the claim that nuclear waste is not pollution. If you eat it, swim in it, breath it, it will kill you. Sounds like a pretty harse pollutant to me!

Leon Brooks said...
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Leon Brooks said...

The cost of radioactives in lives-per-watt is actually quite cheap when compared with coal or even oil.

For a pollution comparison, the Muja powerplant in Collie (WestOz) burns 12 tonnes a year of Uranium, based on parts-per-million in the coal times tonnes burned per year, to produce a terawatt (peak) of electrickery.

If a nuke powerplant lost a single tonne a year, could you imagine the headlines?

Yes, there are bad things about nukes (particularly disposing of the power-plants themselves), but a second look at what we now use is pretty terrifying by comparison.

Wind looks pretty good, although the gadgets in question do wear, and all but the best can emit flying objects. Sun is also starting to look good (now that they're getting their carbon balance equitable). Tidal and similar projects skip most of the intermittency of the above, but have technical issues of their own.

In short, we're on the way to generalised, dispersed, non-fossil, non-nuclear energy, but it'll be a while before we could be said to have made it.

Leon Brooks said...
This comment has been removed by a blog administrator.