Reply to: Renewables - do they have a future?

[BlasterBates]

Hopes Dim for Renewable Power From Ocean Waves and Tides - Businessweek

[VectraMan]

*it's not. The tide is always moving somewhere on the UK coastline since tide times vary by up to (I think) a couple of hours. And if we factor in ocean currents as well as tides, things are even more constant.

Except it's only worth doing in a few places where the tidal flow is high, like off The Orkneys:

Scottish Tidal Energy

The crown estate and Scottish government are behind a £4bn project to build a number of tidal power sites around the Orkney islands and the Pentland Firth, expected to generate the same amount of power as a nuclear power station. That's 1.2GW of green energy - enough to power up to 750,000 homes.

There are those lies again!

[EternalOptimist]

Why not ask the engineers what they think ?
or the people who are willing to risk their own money.


the answer is not only unequivocal, but enthusiastic. a mix of coal, nuclear and gas

with as much despatchable hydro as you can squeeze in

[d000hg]

You might be able to predict it millenia in advance, but it still drops to zero twice a day and rises to a peak twice a day. So reliable in the sense that you know what it's going to do, but not reliable in the sense that you can rely on it alone.

Even if that were the case*, it's far more reliable than "will we get any wind today?" You know exactly how big your 'battery' capacity has to be - enough for a few hours only.

*it's not. The tide is always moving somewhere on the UK coastline since tide times vary by up to (I think) a couple of hours. And if we factor in ocean currents as well as tides, things are even more constant.

I'm sure it's a massive job, but then building ships and oil rigs the size of small towns, and digging coal out of the ground, are also incredibly, bewilderingly massive feats.

[BlasterBates]

Huge hurdles for tidal power to overcome, not least having all your turbines and machinery in sea water. I'm not a big a fan of wind, but compared to tidal it wins hands down.

[VectraMan]

Tidal is pretty darn reliable.

You might be able to predict it millenia in advance, but it still drops to zero twice a day and rises to a peak twice a day. So reliable in the sense that you know what it's going to do, but not reliable in the sense that you can rely on it alone.

[VectraMan]

WHY is renewable energy so hard to crack? We haven't seemingly managed to get wind, solar OR tidal there yet after a lot of work. Only hydro is really proven and that's pretty localised.

Is there something fundamentally difficult about the concept of catching all the free energy?

Wind energy has been cracked. It works as well as it ever was going to, and unless someone can come up with a more efficient way of turning motion into electricity the only thing you can really do from this point is build more. No amount of effort is going to solve the problem of it not working when the wind doesn't blow. Same with tidal really, the technology is there it's just nobody has invested the billions required.

Solar perhaps still has a way to go to be more efficient and cheaper. It strikes me that there are an awful lot of rooves doing nothing all day but absorbing heat and light from the sun (even when it's cloudy). Why isn't every new house being built with solar panels?

[d000hg]

Tidal is pretty darn reliable. And in many locations so is sun - I didn't mean this to be a UK-centric question but a general one.

I personally always thought tidal was the obvious one that is not investigated seriously enough - especially in places like the UK actually. Not only are tides reliable but moving water carries a LOT of energy compared to wind - travelling at the same velocity 1m^3 of water carries 1000X as much energy as 1m^3 of air.

[EternalOptimist]

In an attempt to interrupt the inevitable stream of graphs and insults...

WHY is renewable energy so hard to crack? We haven't seemingly managed to get wind, solar OR tidal there yet after a lot of work. Only hydro is really proven and that's pretty localised.

Is there something fundamentally difficult about the concept of catching all the free energy?

Engineers, the people who actually do the job, the people who convert the science into technology, divide energy production into two types. Despatchable and non-despatchable.

Despatchable energy is available at the point of demand and that's what is required for a grid.
Non despatchable implies rationing, uncertainty, backups, grid problems , additional costs etc.


most renewable energy is non despatchable

[BlasterBates]

In an attempt to interrupt the inevitable stream of graphs and insults...

WHY is renewable energy so hard to crack? We haven't seemingly managed to get wind, solar OR tidal there yet after a lot of work. Only hydro is really proven and that's pretty localised.

Is there something fundamentally difficult about the concept of catching all the free energy?

Yes it's intermittent and defuse, and these are problems usually brushed aside as a "detail to be sorted out" but actually they're massive problems with no solution.

[d000hg]

In an attempt to interrupt the inevitable stream of graphs and insults...

WHY is renewable energy so hard to crack? We haven't seemingly managed to get wind, solar OR tidal there yet after a lot of work. Only hydro is really proven and that's pretty localised.

Is there something fundamentally difficult about the concept of catching all the free energy?

[EternalOptimist]

I remember a few years ago , when we had a cold winter, the eco-loop-fruits were saying that was weather not the climate.
now they take a shorter period and claim it is the climate


why does anyone take any notice of what they say ? beats me

[pjclarke]

Interesting that anyone would choose a satellite record over the surface measurements, rather than loking at ALL the data, for many reasons.

- The satellites measure the temperature of the troposphere, not the surface. In fact they don't measure temperature at all, they measure brightness in the microwave spectrum, which then has to be converted to temperature.

- The data has to be adjusted and then re-adjusted first to convert to temp, then a 'fudge factor' to allow for orbital drift, viewing angle etc etc. In fact the two agencies, RSS and UAH that use the same sat. data come up with different numbers ...

- The satellites don't fly over the poles and so do not even cover the whole globe, RSS only covers 82.5N to 70S, missing out most of the Arctic, where it is warming most rapidly, and the Antarctic where the low viewing angle and the mountains make the readings unreliable.

Incidentally, and even so, UAH just recorded the equal warmest October in its records and 2014 is on-track to be the third-warmest year in that data. Hardly cause for comfort.

And, as pointed out ad nauseum, NASA (GISTemp), for example, does not use urban stations when calculating trends. Does anyone really believe global warming is due to steampipes in Russia?

[BlasterBates]

2014 to Be Hottest Year Ever Measured - Scientific American

not so fast !!, just because it's warmer on the tarmac of a car park or near a heating pipe in Russia doesn't necessarily mean the atmosphere is warmer.

/http://joannenova.com.au/2014/10/panic-2014-hottest-year-ever-no-no-no-say-the-satellites/

None of the investigative hardened editors or science reporters knew enough to ask the question, “what do the satellites say?” Which would have been interesting because the satellites say “bollocks”.

[EternalOptimist]

yep. if the past keeps cooling at the rate it has been

every year will be the hottest. evah!