Hi again KAEP,

I've looked over the dieoff.org site and while I agree with some of the information it presents, much of it is out of date or short-sighted while the main text consists principally of bald assertions of insupportable opinions.

Dieoff.org says the long-term sustainable carrying capacity of Earth is two billion people. The one source given for this figure suggests two billion *reasonably prosperous* people, supposing no alternative energy and chemical-feedstock sources to fossil fuels can be found. The six or more billion people living here now aren't "reasonably prosperous" on average. Thirteen years ago when the paper was written, even fewer were prosperous than are now.

I read and studied the "emergy" discussion which purports to justify the site's complete dismissal of renewable energy.

This waffle and its impenetrable source grossly overestimate the "embodied energy" of fossil fuels by trying to trace the energy source back to the sun. The process of conversion from living biomass to fossil fuel was extremely inefficient and did not involve any highly-evolved 'maximum power' organisms, merely geological processes. We can do much better with contemporary biomass.

The "emergy" page then inappropriately compares this overestimate of the fossil-fuel energy consumption of the profligate USA to solar radiation presently directly absorbed on the land area of the USA (the Earth as a whole does much better, as much of it is dark ocean and rainforest, while the continental USA consists largely of high-albedo desert, pasture and grain cropland) instead of to the enormous total flux of solar energy which is available for capture on Earth.

Five points still outstanding:

* Petroleum represents less than 40% of present energy use. Renewable energy represents 13% and growing.

* Sound management (admittedly lacking to date in most countries) can reduce demand for petroleum, faster than any decline in production.

* There is no present-day shortage of stationary energy.

* Any carbon-bearing combustible fuel (such as coal or biomass) can be transformed chemically into high-quality liquid fuels which substitute for petroleum.

* Conversely, your pet technologies of geothermal and nuclear power cannot readily substitute for liquid fuels.

> * Petroleum represents less than 40% of present energy use. Renewable energy represents 13% and growing.

Really? Are those Australian statistics for liquid fuels? I'd like to see some sources for that - sorry if you posted it somewhere previously.

> * Sound management (admittedly lacking to date in most countries) can reduce demand for petroleum, faster than any decline in production.

If by sound management you mean severe austerity measures such as rationing & greatly increased taxes for personal use, combined with an urgent investment in massive public transport ... then maybe you're right. Can't see it happening otherwise, and I can't see our politicians being brave enough or far-sighted enough to implement it anyway.

> * There is no present-day shortage of stationary energy.

Our stationary energy, being mostly coal-based, needs liquid fuels to mine & transport the coal. When liquid fuels go higher in price due to scarcity it will logically have an impact on the cost & availability of stationery energy. When there's supply disruptions due to peak oil production, stationery energy will start to falter as well.

> * Any carbon-bearing combustible fuel (such as coal or biomass) can be transformed chemically into high-quality liquid fuels which substitute for petroleum.

Yes, but again there's problems. Coal to liquids can be done at an incredibly high cost in CO2 emissions. Have you seen Graeme Pearman's latest report on climate change? Growing biofuels has taken large tracts of land away from growing food crops & consumes scarce water supplies.

> * Conversely, your pet technologies of geothermal and nuclear power cannot readily substitute for liquid fuels.

Nuclear, like coal, relies on liquid fuels to mine & transport the uranium. The core problem with peak oil is that in making liquids scarcer and therefore more expensive, all other forms of power generation become harder & more costly to do - some more than others.

Its a pity Abner Doble's steam car never caught on :)

Commuter,

You are correct re:nuclear but note, once you set up high energy density power generation systems such as nuclear and geothermal, they are NET-energy-produers, 100's times moreso than renewables. Nuclear/Geothermal MMST (manufacture/maintenance/storage/transport) energy usage is sustainable whereas renewables' are not. Nuclear can crack water into Hydrogen and mass-synthesise liquid fuels. Renewables cannot. Thus Nuclear can support itself with net energy and liquid fuel gains. It becomes clearer why renewables alone can never support 6 billion people let alone the 9 billion projected for the 2025 population crunch.

Also, vastly distributed renewable systems are a maintenance nightmare (imagine the army needed to clean square miles of photocells) especially when petrol prices creep past $5/litre. I envisage that renewable systems will not be worth maintaining at that early-juncture. Current investments will be wasted.

If the human race is to survive the next 20 years it MUST stall population growth globally to 7 billion people (one-child-per-family policy), and commence introducing Nuclear&Geothermal power stations.

Few people agree.

However with certain Thermodynamic knowledge I have garnered from watching/analysing 6 US hurricane seasons (Thermodynamic events on a 3-surface manifold) I will state that at about $5/litre(petrol) certain movements in societal values (thermodynamic trajectories in things like value of human life) are going to shock world leaders to an extent that nuclear/geothermal/one-child-per-family implementaion programs will be fast tracked right across the globe.

The alternative will be a series of wars that can hardly be contemplated by demure,selfish and gullible world citizens of today.

There will be those who will prefer war(we know who they are) because they foolishly expect to win. But I can assure people that at above $5/litre the end-of-civilisation consequences of that stupidity will have already begun to show. No-one can or will win anything in a 9 billion people random chaotic crunch.

ITS ALL THERMODYNAMICS ... its not that long to wait and see.

In order to protect our fragile environment and insulate ourselves from an imminent world chaos&tyranny and show some altruism and decency in world leadership, Australia must go Nuclear/Geothermal/one-child-per-family ... sooner ... not later.

KAEP,

You write,

"Nuclear can crack water into Hydrogen and mass-synthesise liquid fuels. Renewables cannot."

I know of no technology that can convert nuclear energy into liquid hydrocarbons. Please provide a reference.

Biomass already provides liquid fuels. Nuclear energy does not.

Nuclear power can produce hydrogen by high-temperature electrolysis, which works just as well with solar energy, and which is more expensive than steam reformation of hydrocarbons.

Vast quantities of petroleum go to waste every day. With a minimum of effort most of this wastage could be prevented. For you, this resource doesn't exist.

Are you the kind of person who wouldn't stoop to pick up a $20 note lying on the ground, because if it were possible someone would already have done it?

Commuter,

The figure of 40% reliance on petroleum for primary energy is global. In Australia we use *less* petroleum than average (32% of primary energy) but more natural gas (19%) so our total reliance on the "fluid" fossil fuels that are expected to peak relatively soon is heavier than most. We use much less renewable energy than the world average, 6% as opposed to 13%, because we use less firewood and hydroelectricity than most countries. We lack a good hydro resource, but we certainly could make much better use of our biomass potential.

Coal mining doesn't require oil if electricity is available, and it invariably is. Yes, we use a lot of oil today hauling coal, because until recently it was cheap and convenient. But more of the extractive equipment is powered by electric motors than by internal-combustion engines. Converting railways and the remaining digging equipment to electric operation would be simple and, at today's oil prices, cost-effective.

But actually the best way to reduce coal mining's oil demand is to reduce coal mining, for burning coal is a very wasteful way to produce electricity. There are better ways that require less oil.

Uranium mining equipment also prefers electricity, though often this is provided by diesel or LNG-powered gensets at remote sites, and such long-distance haulage is obviously not suitable for inexpensive electrification.