Roger B said:

 Is there any engineering behind this?

It's a political decision (and not in a bad way).  Nothing to do with engineering.  You decide that something needs to be done, then ask an engineer how to do it.

Roger B said:

Are there sufficient resources available?

I'm sure there are if we want there to be.

Roger B said:

How much more fossil fuel will be consumed producing these alternative energy sources before they become in some way self-sustaining'?

Quite a bit.  But extracting, refining and transporting fossil fuels uses a lot of fossil fuels.  As does building fossil-fuel powered power stations.

But the more renewables you build, the less fossil fuels you need going forwards.

Roger B said:

1) They are entirely shareholder driven, it is their fiduciary duty to maximise profits by staying with oil and gas and they don’t see a risk of ending up with ‘frozen assets’.

2) They don’t want to see the world run out of energy when renewables can’t deliver.

I'm sure it's entirely option 1.  We're talking about oil companies here.

Roger B said:

 Is there any engineering behind this?

It's a political decision (and not in a bad way).  Nothing to do with engineering.  You decide that something needs to be done, then ask an engineer how to do it.

Roger B said:

Are there sufficient resources available?

I'm sure there are if we want there to be.

Roger B said:

How much more fossil fuel will be consumed producing these alternative energy sources before they become in some way self-sustaining'?

Quite a bit.  But extracting, refining and transporting fossil fuels uses a lot of fossil fuels.  As does building fossil-fuel powered power stations.

But the more renewables you build, the less fossil fuels you need going forwards.

Roger B said:

1) They are entirely shareholder driven, it is their fiduciary duty to maximise profits by staying with oil and gas and they don’t see a risk of ending up with ‘frozen assets’.

2) They don’t want to see the world run out of energy when renewables can’t deliver.

I'm sure it's entirely option 1.  We're talking about oil companies here.

Simon,

You have highlighted some of the key points here:

‘By 2050, no energy must come from fossil fuels’

It's a political decision (and not in a bad way).  Nothing to do with engineering.  You decide that something needs to be done, then ask an engineer how to do it.

Is it just a political decision then, not based on any science? Do the people setting these ‘political’ targets actually know what they are talking about?

Are there sufficient resources available?

I'm sure there are if we want there to be.

All these resources, metals, plastics, concrete, space, etc. are finite. It is not just a matter of wishing there to be enough. The given target, ‘By 2050, no energy must come from fossil fuels’, needs calculations to determine what will be required to replace all the heat energy used in metal and concrete manufacture with electrical energy. This includes the very high losses if hydrogen is used .  

How much more fossil fuel will be consumed producing these alternative energy sources before they become in some way self-sustaining'?

Quite a bit.  But extracting, refining and transporting fossil fuels uses a lot of fossil fuels.  As does building fossil-fuel powered power stations.

But the more renewables you build, the less fossil fuels you need going forwards.

This also requires some significant calculations. If you believe the climate science your ‘Quite a bit’ will further increase global temperatures and probably push past a tipping point. Does that mean we are doomed anyway? Probably not, but some good simulations will give a rate of conversion to alternative energy sources that will minimize the consumption  of fossil fuels. This requires science and engineering, not a ‘political’ target of 2050.

Is it just a political decision then, not based on any science?

Te two aren't mutually exclusive - most governments are advised by various learned committees who presumably do know their stuff.

  - Andy.

One may look at the line mega city as an example of an oddly conceived vanity project,   or at least as the sort of thing that I hope would never gain traction in Europe, yet that will have plenty of respected experts working on the designs and planning. If it really is using 20% of the worlds steel for the foreseeable future, as that link suggests, then its a good job that there aren't 5 places on the planet trying to do the same  scale of thing at once.

Not all state driven projects necessarily stand up to the 'is it sensible? ' test.

Mike

PS and if sense came into it, albeit at a far more modest scale, in the UK we'd have built the northern legs of HS2 first, then cancelled the southern bit not the other way about....

Roger B said:

You have highlighted some of the key points here:

‘By 2050, no energy must come from fossil fuels’

It's a political decision (and not in a bad way).  Nothing to do with engineering.  You decide that something needs to be done, then ask an engineer how to do it.

Is it just a political decision then, not based on any science? Do the people setting these ‘political’ targets actually know what they are talking about?

It should be based on science.  But the politicians make the decisions, not the scientists.

Roger B said:

Are there sufficient resources available?

I'm sure there are if we want there to be.

All these resources, metals, plastics, concrete, space, etc. are finite. It is not just a matter of wishing there to be enough. The given target, ‘By 2050, no energy must come from fossil fuels’, needs calculations to determine what will be required to replace all the heat energy used in metal and concrete manufacture with electrical energy. This includes the very high losses if hydrogen is used .  

The more oil and gas that we don't burn, the more we have left to make into plastics and useful stuff.

Roger B said:

How much more fossil fuel will be consumed producing these alternative energy sources before they become in some way self-sustaining'?

Quite a bit.  But extracting, refining and transporting fossil fuels uses a lot of fossil fuels.  As does building fossil-fuel powered power stations.

But the more renewables you build, the less fossil fuels you need going forwards.

This also requires some significant calculations. If you believe the climate science your ‘Quite a bit’ will further increase global temperatures and probably push past a tipping point. Does that mean we are doomed anyway? Probably not, but some good simulations will give a rate of conversion to alternative energy sources that will minimize the consumption  of fossil fuels. This requires science and engineering, not a ‘political’ target of 2050.

We don't know if there is a specific tipping point, or where it is.  So introducing decision paralysis by asking for all the calculations before you start doing anything is a good way to ensure that we never stop burning fossil fuels.

Which is what many people want.

I predict that as more places flood, more coral and forests die and folk become aware that there really are far more people wanting to live on the remaining warm and dry bits of the planet that will comfortably fit, there will be a sharp change in attitude to a lot of the 'process' that gets in the way. (planning, safety studies, consultations budget uncertainty)
Look how quickly things could be done in lockdown if you like for an example of that.
You can also look at that as an example of how wasteful such a 'panic at the latest moment possible' approach can be, but like the kids doing homework on the bus into school , it is very human for adults as well to under-value getting things done early.

Mike,

I would like to believe that the government has intelligent and wise advisory groups, but I see no signs. What I do see is lobbying groups looking for government (taxpayer) subsidies for their favorite solution. If there was any sign of joined up thinking we should be seeing the power transmission infrastructure being built up to support the installation of wind and solar power generation along with suitable storage and stabilizing systems.

Don’t worry though Ed Milliband has the solution, ‘Flywheels’.

https://www.msn.com/en-gb/money/other/ed-miliband-reveals-plan-to-prevent-net-zero-blackouts/ar-AA1rz1Nd

If there was any sign of joined up thinking we should be seeing the power transmission infrastructure being built up to support the installation of wind and solar power generation

Like this sort of thing? https://www.nationalgrid.com/the-great-grid-upgrade

Don’t worry though Ed Milliband has the solution, ‘Flywheels’.

Well "rotary UPSs" are well established technology (both with and without diesel backup) - perhaps more suitable to short term and grid stabilization (e.g. adding back a bit of "inertia" to the grid to help ride over sudden changes) rather than mass inter-seasonal energy storage, but they have their place I'm sure.

   - Andy.

Yes, exactly what I said, reactive and 10 years (at least) too late. This should have been progressing in parallel with the planning and installation of large wind and solar farms.

As ever there is not enough information about the proposed flywheels but I don’t think that they are synchronous motors attached to large rotating masses that is what is needed for grid inertia and frequency stability. The ‘thousands’ of rpm suggests and inverter system rather than direct coupled that would be simply 3000rpm.

The calculations are necessary to ensure that money and resources are not wasted. They are usually ignored as the answers may not be so palatable to the political and environmental elite who want the money. It’s all about the money as Oxfam has discovered.

https://www.oxfam.org/en/press-releases/41-billion-world-bank-climate-finance-unaccounted-oxfam-finds

There have been many studies caried out into the true benefits (or not) of  renewable energy sources. The problems of biomass are obvious, here is a recent paper and a couple from around ten years ago on the true EROEI for solar PV:

https://environmentalprogress.org/big-news/2023/7/3/solar-panels-are-more-carbon-intensive-than-experts-will-admit

https://energyskeptic.com/2015/tilting-at-windmills-spains-solar-pv/

https://www.resilience.org/stories/2015-05-11/how-sustainable-is-pv-solar-power/