Water power

[JimC]

Seems to me there is energy/power everywhere. Harnessing it is the issue.

There is, but none of it is truly "free".

In the sense that its harnessing creates consequences which must be dealt with...

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

I was thinking of the trapping of sediments behind dams, and the potential interruption of riverine piscine migration patterns...

I would have thought that photo-voltaic panels on domestic roofs were also fairly free, other than the energy used to manufacture and transport them...

[rainbow]

.
Any salmon or trout in there? They wouldn't like those turbines at all.

The fingerlings that go through the turbines end up as fishpaste.

[Thinking Aloud]

Seems to me there is energy/power everywhere. Harnessing it is the issue.

There is, but none of it is truly "free".

In the sense that its harnessing creates consequences which must be dealt with...

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

I was thinking of the trapping of sediments behind dams, and the potential interruption of riverine piscine migration patterns...

In theory there's no need for the dam to be a reservoir if we're just considering gravity, and are prepared to accept variations in flow rate, but yes, fish ladders and other eco measures in order.

[Gawdzilla Sama]

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

How about a water wheel in a waterfall above a natural catch basin?

[Thinking Aloud]

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

How about a water wheel in a waterfall above a natural catch basin?

The water would give up energy to the waterwheel, thus be less erosive in the splashpool. Not a problem in itself, and certainly not on the timescale over which the waterwheel would be operational.

[Gawdzilla Sama]

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

How about a water wheel in a waterfall above a natural catch basin?

The water would give up energy to the waterwheel, thus be less erosive in the splashpool. Not a problem in itself, and certainly not on the timescale over which the waterwheel would be operational.

The net change would have a negligible effect over even a few hundred years.

[Jason]

Near one of the places I spent my childhood was an experimental type of hydroelectric plant. It was very small, but diverted almost the entire river into a concrete tube which was about 50 meters long by (guessing because it was mostly submerged) 6 meters in diameter. I say almost because when the river was high some of the water would flow over the concrete tube instead of into it. I've never seen another design like it.

[Pappa]

Seems to me there is energy/power everywhere. Harnessing it is the issue.

There is, but none of it is truly "free".

In the sense that its harnessing creates consequences which must be dealt with...

Yes. Though gravity-based systems (river and tidal) seem to be the least consequential - stealing energy from falling or moving water theoretically means there's less energy available for erosion downstream.

I was thinking of the trapping of sediments behind dams, and the potential interruption of riverine piscine migration patterns...

I would have thought that photo-voltaic panels on domestic roofs were also fairly free, other than the energy used to manufacture and transport them...

Photo-voltaic cells are probably the least efficient of the common renewable energy sources. The cells use a huge amount of energy to manufacture, and as an industry, PV cell manufacture has only recently become a net producer rather than consumer of electricity.

[Cormac]

Photo-voltaic cells are probably the least efficient of the common renewable energy sources. The cells use a huge amount of energy to manufacture, and as an industry, PV cell manufacture has only recently become a net producer rather than consumer of electricity.

But they've become dramatically cheaper to produce.

The point about them is that they'll last at least 25 years. Clearly, during that time, they'll catch up on, and exceed the carbon released in their manufacture. After that, the energy is primarily clean.

The more PV panels out there, the more likely that some of the power inputs to their manufacture will be solar in origin - and that is when the industry will become cleaner, delivering operating benefits from day one. Large scale installations - i.e. South facing Mountain slopes in the Northern Hemisphere covered in PV.

[JimC]

Photo-voltaic cells are probably the least efficient of the common renewable energy sources. The cells use a huge amount of energy to manufacture, and as an industry, PV cell manufacture has only recently become a net producer rather than consumer of electricity.

But they've become dramatically cheaper to produce.

The point about them is that they'll last at least 25 years. Clearly, during that time, they'll catch up on, and exceed the carbon released in their manufacture. After that, the energy is primarily clean.

The more PV panels out there, the more likely that some of the power inputs to their manufacture will be solar in origin - and that is when the industry will become cleaner, delivering operating benefits from day one. Large scale installations - i.e. South facing Mountain slopes in the Northern Hemisphere covered in PV.

And, other than the costs and energy involved in their manufacture, they have no other worrisome side-effects - they can just sit there on the roofs of domestic and commercial buildings, quietly reducing the amount of electricity that needs to be generated in other ways, and eventually saving their owners a heap of money, particularly as it is highly likely that electricity prices in most of the world will rise steadily...

[Gawdzilla Sama]

Places like Mexico could become net exporters of power. The Sahara could bloom with desalinated water produced by plants powered by sunshine.

[Xamonas Chegwé]

Places like Mexico could become net exporters of power. The Sahara could bloom with desalinated water produced by plants powered by sunshine.

Or... the rich could just keep on getting richer while fucking up the planet. Who can guess?

[Gawdzilla Sama]

Places like Mexico could become net exporters of power. The Sahara could bloom with desalinated water produced by plants powered by sunshine.

Or... the rich could just keep on getting richer while fucking up the planet. Who can guess?

Kill enough of them and they might change their habits.

[Cormac]

Places like Mexico could become net exporters of power. The Sahara could bloom with desalinated water produced by plants powered by sunshine.

Or... the rich could just keep on getting richer while fucking up the planet. Who can guess?

Or the EU and Saharan states could enter an extended phase of mutual dependence and benefit.

[rainbow]

Places like Mexico could become net exporters of power. The Sahara could bloom with desalinated water produced by plants powered by sunshine.

Deserts are ecosystems in themselves. Destroying them by making them bloom is NOT environmentally friendly.