Warmair, I think you underestimte the problem.
I had thought that with oil not being available we would need to do
everything electrically.
The reason; that by 2050, everything will have to be done electrically
is that world peak coal is expected about 2025 plus the quality of
coal, ie the heat value per ton, is decreasing together with oil
being too expensive to burn.
You made a suggestion about on farm energy generation, which is very
valid, but it is just touching the edges of the problem.

However Peter Lang pointed me to an article where a study had been
done on the amount needed to replace oil, gas & coal.
It comes to five times our present generation. Bit of a shocker that !
If we were to attempt to do it with solar & wind we would have to have
20 times present generation at minimum plus an equal amount of storage.
I suspect that it is already too late, there will not be enough money
available in the world to do the job for the worlds generation.

I just cannot imagine it, can you ?

Bazz

The answer is I see no practical problem going to 100% renewable.

http://en.wikipedia.org/wiki/Renewable_energy
http://www.pwc.co.uk/assets/pdf/100-percent-renewable-electricity.pdf
http://www.ies.unsw.edu.au/docs/100pc_Renewables_SolarProgress.pdf

The problem is simply one of cost.

The first problem is that people who have invested large sums in current fossil fuel technology will not want to see their money going down the drain. Nor will the miners be to happy about their loss of fossil fuel assets.

The second problem is raising the cash to make the change over.

Thanks for those links.
The very large one, I have not attempted to read.
The last won refers to the zero groups proposals.
Now these are all well thought out systems, although many "in the know"
doubt whether they really are practical.
One of their objections is that there is no solution to storage.
The proposals seem optimistic as to the prospect of achieving
sufficient storage.

However since reading the paper pointed to by Peter Lang I just cannot
see it being anywhere near practical.
Think about it, providing, installing & maintaining solar & wind
equipment to provide TWENTY times the present generating capacity
PLUS 5 times the capacity of storage !

No, there is not enough money to build 150 gigawatt of nuclear power
stations over the years.
Pity, it is just not practical.
No, buy a farm instead.

Bazz

http://srren.ipcc-wg3.de/

There are plenty of reputable scientists who believe we can get to 80% renewables by 2050.

The cost is around 1% of GDP for the whole world and I would have thought once the change over is made it would it actually increase GDP.

In my local area I know of a number of places that are off the grid, operate all the mod cons, and not only do they have adequate power at all times, on sunny days their batteries are fully charged before midday. One chap I met claims his batteries never fall below 75% charge. In most cases the reason they chose the renewable path was simply because once the distance to the grid connection is more than about 1 kilometer (cost $50,000) it is much cheaper to install your own system. The cost of a complete stand alone system for a typical 3 bedroom house starts around $25,000 which considering the price most people pay for a new house these days looks to me like a bargain.

Warmair,
The people you quote are all missing the point.
They are not quoting for the real problem, just replacing present generation.
Currently, pun intended, we have 6 Gwatt of generating capacity in
Australia I believe.
Their proposals are to replace our present generating capacity.
That is not the requirement.
The requirement is for 150 Gwatt of solar & wind !
The requirement is also for 30x12 Gwatt hours of storage.
The figures get to this level because if everything, including
transport has to be run electrically we need five times out present
generation, so 6 x 5 = 30 G watt from base load nuclear.

Solar & wind are at best 25% nameplate capacity. So 4 x 30 = 120 Gwatt
but you would need a bit more for safety, say 130 Gwatt.
Then storage to run all night, say 12 hours, 30 x 12 Gwatt/hrs.

We could not afford that now, let alone while the economy is contracting.

Now I agree these figures are rubbery but they do illustrate the problem.

Bazz

It is clear from the link below that they do not intend to simply use electricity as the sole source of power nor is it very a sensible idea. For example generating solar power to run an electric hot water service is not a smart thing to do. nor is it correct to compare a fossil fuel engine with an efficiency of around 20% to an electric motor which can achieve nearly 90% efficiency.

The link does not miss the point it clearly says that the idea is to replace 80% of all fossil fuel use with renewables by 2050. It also makes it clear that we have the technical skill and resources to achieve this. This is on a world wide basis not just Australia.

There is a lot of interesting stuff in summary so at this stage I have not had time to read it in full.

http://srren.ipcc-wg3.de/report/IPCC_SRREN_TS.pdf

See page 42