@Peter Mac: I simply don’t know the answer and will be very interested in responses and/or references to any research that has been done in this regard.

I think it's fair to say no one knows the answer. There was one recent paper looked at the energy entering the atmosphere vs how much we take out as wind. Basically you can't take out more than you put in.

The real question is what is the likely hood of renewables externalising a lot of their costs. That for me is the real danger. Coal is a problem because the cost of dealing with the CO2 its dump into the atmosphere isn't passed on in it's products. Ditto for nuclear. A single nuclear accident can cause so much damage it can't be paid for by the owner of the plant, or realistically insured against. So society wears the damage. Society also wears the cost of proliferation and the long term waste disposal. When we externalise costs like this, we run into danger of deploying far more than we can actually afford in the long term. That is in effect what may be happening with coal.

If you try hard you can envisage some renewables externalising costs - such as geo-thermal causing earthquakes, and maybe wind removing so much energy from the atmosphere expected efficiency of wind turbines goes down. But gee it's hard, and usually far fetched.

By the way, it appears you can design nuclear plants that don't externalise their costs. They burn most of their fuel, they are small enough that if they do go bang (to coin a phrase - they never literally go bang) the damage can be borne by the owner, and their wastes a both small and relatively short lives - relative to 10,000 years anyway. But they are more expensive. Nonetheless, I think if you want to fairly compare the costs of renewables to nuclear, if should be done with this style of plant. Not behemoths like Fukushima that only burn 0.8% of their fuel.

Peter Mac, I can give you my considered response to your questions but I’m not going to get into “link wars”. My responses to your question have been covered by previous submissions and supporting references, you will have to follow up those for yourself.

Since you seem genuine enough I’ll give it my best shot.

Should we switch to renewable sources of energy?

Yes, when it is technically, commercially and economically viable, which sadly it isn’t, even with public capital investment and energy tariffs. Additionally, advanced nuclear fission/fusion, hydrogen technologies will be available long before renewables reach maturity. They are at best “transitional” technologies and we absolutely must use current technologies to create future technologies. It is suicidal at any pace, to abandon what we have for what don’t yet have.

Could extracting too much energy from natural sources change the global climate?

Not sure what you mean by “extracting”?

Harvesting solar, wind and wave energy “extracts” nothing, converts yes, but extracts? No.

Could these processes “change global climate’?

At what renewables utilization are you assuming? It seems that any attempt to go beyond 20% is futile dream world. How on earth do we get the idea that 20% renewables, which requires “spinning backup” from base load generation, can be any value. The more renewable generation we build the more conventional backup we will need. If we can’t make a case that conventional power generation causes a problem, how can renewables cause such a problem?

IMHO, future generations will make current generations a laughing stock. We have a rapidly crumbling phenomena supported by increasingly flakey science upon which we are trying to make global decisions on energy.

They may be kind to us and say, Oh Grandpa; you didn’t really believe all that did you?

I guess we are now about to find out if you are baiting?

Over to you.

Peter Mac;
There is not much dobt that exposing solar cells to the sun will have
negligable effect. The solar cells are not very efficient so the great
majority of the sun energy landing on them is converted into heat.

Similarly with wind mills, they just tap a small amount of energy from
the wind stream going past.
No, the only co2 question is how much CO2 is produced in manufacturing
and installing those systems.
How much time does it take those systems to repay the debt of co2 ?

But then that does not matter anyway. CO2 is not a problem in the
scale of the transition that we face.

There are bigger questions to ask that many ignore.
Instead of getting as much gas out as possible to sell overseas, we
should only install a few gas wells on each farm and keep the smaller
amount of natural gas for ourselves for our use in the coming
transition to whatever alternate energy system we end up using.

The same applies to coal, we are going to need a lot of coal to build
the steel structures needed for the alternate systems.
Peak coal world wide is expected around 2025 and is expected to
deplete quickly as the quality falls quite steeply.

We have large deposits of coal so peak coal in Australia is long past
2025 if we stop exporting it. No one knows how long it will take to
replace our present generating capacity with the base load power that
we will need in by that time.
Won't we be kicking ourselves if we have let the Chinese burn it all ?

Thank you for the responses so far. You may gather that I sit on the sceptic side of the AGW discussion but I’m always keen to tackle any issue from different perspectives and always interested in the cause and effects of actions, especially inadvertent effects.

Hence my question – if we (hypothetically perhaps) convert 14,000 TWh worth of energy from the wind, sun and waves into electricity and this is equivalent to 8% of the solar energy falling on the surface of the planet, I expect that this must have some material effect on the energy balance that drives our climate. It would be a big boo-boo to save the planet from disaster by reducing CO2 levels only to find the alternatives cause climatic effects as well. The introduction of the cane toad to Australia is my fable here. The fictional Andromeda Strain also springs to mind – they realised just in time before the detonation of a “defensive” thermonuclear device that the virus fed on pure energy.

bonmot – I will check out the links, thanks.

rstuart – thanks for expressing the issue in terms of externalising costs, whether they are commercial costs or environmental / social costs. This concept should be the essence of any proposal whereby all the costs & benefits must be assessed. At the moment, we are extracting energy from coal and oil (bear with the clunky terminology spindoc) and some suggest the “cost” of this is the gaseous product of combustion / oxidisation. From an energy balance point of view, the actual extraction of the coal & oil from the ground has little effect because the energy content is otherwise dormant. However, taking wind energy as an example, we “extract” kinetic energy that should be busy doing something else. At some quantum, this will affect the “something else”, which I suggest is probably the global climate. It is a question then of whether this affect is material and the consequences of such.

To be continued ...

Continued ...

spindoc – thanks for your faith and for not getting into the “link wars” – I will look at your other posts, thanks. My question was based on the assumption that technology will allow 100% conversion of fossil-based electricity to renewable at some time. But, “renewable” energy is not “free” energy – it doesn’t just spontaneously appear. As you have correctly pointed out, it must be converted from some other form. So, will the conversion of 14,000 TWh cause a material effect? I think that the answer is “maybe, and we should look into it” before we spend an enormous amount of money to replace the current sources of power. Renewable technology and costs will not improve if there is low demand and that’s the current quandary – too expensive and therefore nobody wants it. The aim of carbon pricing schemes is to reduce the price differential to make it commercially competitive but in the short term (5 years or 50 years?) will just raise the cost to the consumer for power from all sources. To come out of the other end of this huge investment only to find we have caused the very problem we thought we were solving will make your grandkids shake their heads even more.

Bazz – see comments above – I assume that we could generate all the fossil-fuel power from renewables. Efficiency is just a numbers game, whether you need one turbine at 100% efficiency or ten running at 10% efficiency to generate one MWh is not important to the question – we have still converted 1 MWh of wind energy to electricity. However, you have raised the interesting issue of “cost” in line with rstuart’s post that is driven by efficiency – how much coking coal is needed to produce the steel to build the turbine towers to replace the steaming coal otherwise burnt to generate power? We might not have enough!? The question of the range of possible reactions from China if we stopped selling them coal is for another thread.

Peter Mac,

Some balanced perspectives there but don’t get too bogged down in the detail, particularly the economics.

Think of it this way, each technological step function has at least two iterations; the first is always “interim” or “transitional”. Our current efforts to use renewables can only be an interim technology although they may always be in the mix for geographic reasons, but they will always be dependent upon base load. We know this because we are trying to force technologies that are not mature. We force them through subsidies and consumer tariffs, a CO2 tax is “both”, that is why is it increasingly seen as deceitful. It’s an economic “market forcing” and nothing to do with emissions.

So what will the next step function in energy generation look like?

We can “describe” its inevitable characteristics without actually knowing its technological composition. It will probably be much more localized, more units, smaller units, serving local communities, infrastructure and industries. This might mean less transmission grid infrastructure, less energy/fuel transportation, vastly improved and viable public transport, increased desalination and probably the economically viable production of alternative fuels for transport, probably hydrogen.

The combination of these will unquestionably result in increased food production, more growth and prosperity in rural/regional areas, greater sustainability central and urban communities.

At a national level our dependence on fossil fuels will diminish both costs and emissions, new value added industries will emerge as the cost/value proposition changes to an “enabling” framework, which it the exact opposite of the current “inhibiting” framework of the proposed emissions taxing regime.

This inhibiting framework is stunting market based development in our future, we are forcing it into only “interim” technologies and sadly, things have never, ever, worked that way.

The big picture looks very good for the future, we just need to stop “ideological fairyland” from blocking our access to that future