Aidan,

At least you have taken the first step in admitting that renewable power needs to be backed up by fossil fuel driven generation. Hydro electricity is the closest renewables have to a base load, and Tas uses it to export power at peak times. The backup is expensive gas generation.

Unfortunately, the opportunities for Hydro are limited, and obviously the greens would stop anything that looks like progress.

Shadow,

At least you have taken the first step in admitting that dedicated baseload power generation is not essential for a reliable supply.

Whether renewable power needs to be backed up by fossil fuel driven generation depends on how much (and what type) of renewable power there is. However a backup is essential whatever our energy source, and I expect us to retain the ability to use fossil fuels long after we cease to use them in normal operations.

More wind turbines would now be just as effective for Tasmania as another dam.

.." a backup is essential whatever our energy source"

Really? What backup do nuclear and FF based power need on grid?
Renewables have their place, OFF-GRID.

The idea that renewables will supply major grids with energy that is comparable in cost (including running and infrastructure) to nuclear and FF base-load is fantasy. "Free" energy is not free.

The cost of replacing the base-load fuel with renewables and storage is of a scale that is completely unaffordable.

If the aim is 50% renewables, why? Is this picked out of the sky? I see little value in replacing FF'ed grids with renewables plus backup. This can only REDUCE emissions rather than remove them virtually 100% by going nuclear. We haven't the time to bugger around with expensive fantasy half-measures.Let's go with what's worked in France, for 50 years!

Aidan,

In order to educate you I need to start from the very beginning with a few definitions:

1 Generation = electrical supply
2 Load = electrical consumption
3 baseload = the minimum level of demand on an electrical supply system over 24 hours.
4 Baseload plant is an energy station devoted to the production of base load supply
5 Peak load = short term high level demand over a 24hr period
etc

Baseload plant essentially has to be able to continuously supply a minimum level of power on a 24/7 basis, and can come in the form of coal, nuclear, gas, or even renewables coupled with gas. Large high efficiency turbines driven by coal or nuclear boilers are typically by far the cheapest suppliers of power, they have been used as base load supply.

Peak load supplies are typically those that can fired up quickly such as gas turbines, but cost up to 5x as much per unit of power required, but as the peak price for power can be as much as 20x, these generators can pay for themselves. Wind/solar already costs far more than coal generation, combined with gas this is vastly more expensive.

So a reliable power supply is theoretically possible with renewables combined with a vast network gas generators, but the cost of the power would eliminated virtually all industry and push the cost of living through the roof.

Luciferase,
"Really? What backup do nuclear and FF based power need on grid?"
Yes really. Normally fossil fuels are used for the backup even when the main supply is FF based.

"Renewables have their place, OFF-GRID."
Indeed they do. They also have a much bigger place ON GRID.

"The idea that renewables will supply major grids with energy that is comparable in cost (including running and infrastructure) to nuclear and FF base-load is fantasy. "Free" energy is not free."
It's not free, but it's cheap. And as long as the interest rate is sufficiently low, it's cheaper than any other alternative. It puzzles me why so many people have such trouble comprehending that.

Low interest rates benefit nuclear over FF, but nuclear's higher running cost means they benefit renewables more.

"The cost of replacing the base-load fuel with renewables and storage is of a scale that is completely unaffordable."
What do you regard as affordable, and why?

"If the aim is 50% renewables, why? Is this picked out of the sky?"
Progressing to 100% renewables takes time. 50% by 20xx is an interim target.

"I see little value in replacing FF'ed grids with renewables plus backup."
Then you should think about it more. How much do you expect the backup to be used? How much do you think the backup would have to be used for it only to be of little value? Could the backup be run on gas from biological sources?

"This can only REDUCE emissions rather than remove them virtually 100% by going nuclear. We haven't the time to bugger around with expensive fantasy half-measures. Let's go with what's worked in France, for 50 years!"
Even in France they haven't managed to remove their emissions virtually 100%.

Shadow,

I'm glad you understand the definitions. But your statement about the cost of renewables is an oversimplification: The infrastructure for wind/solar costs far more than coal generation, but the running costs for wind/solar already costs far LESS than coal generation. Thus wind and solar have the potential to reduce baseload prices far more than coal or gas ever could.

A solar thermal plant could be designed to supply baseload, but it would be more profitable for its owners, and more economically advantageous to the customers if it's designed for peakload instead.