RSPB and renewable energy

[Penners]

I hardly think that 10 - 30 rpm constitutes "whizzing"!

 

[MdB]

I hardly think that 10 - 30 rpm constitutes "whizzing"!

Tip speed = 6 to 17m/s if figures from both pages tie up. That is a fair speed in water.

 

[Penners]

Oh, don't come your "metres/second" with me! Whatever happened to good old mph? I could understand that! :wink:

 

[MdB]

Google is your friend.

 

[wobs]

CO2 output from electricity generation by g/kWh:

Conventional coal 1000 g/kWh
Combined cycle gas turbine (CCGT) 500 g/kWh
Photovoltaic 58 g/kWh
Nulcear (life cycle) 5 g/kWh
Wind 5 g/kWh
Hydro (run of river) <5 g/kWh

From TCE magazine (chemical engineering)

 

[Penners]

But what do those figures include? Do they take into account the carbon footprint of building the equipment and disposing of it afterwards?

 

[wobs]

Its for the life cycle of a whole power plant, not just the fuel cycle.

Note also that enrichment calculations were for either centrifuge or difusion, but new techniques such as laser will reduce the enrichment energy cost considerably.

The life cycle includes decommissioning. This also will in future cost less energy, as building such a plant (especially in the EU) requires that decommissioning is accounted for as part of the planning application, unlike older nuclear plants where such things were not considered.

The design of the whole cycle is becoming much more efficient even today, and will continue to progress for decades to come. This means that less energy will need to be consumed to produce it in the future, and past studies that are cited were based upon older plants that used more energy than today's designs.

 

[biffvernon]

"From TCE magazine (chemical engineering)" is insufficient for a source. The figure for nuclear clearly comes from Fairyland.

 

[wobs]

Its a professional magazine that deals with all energy technologies fairly. That's not fairyland.

The numbers vary for energy costs of all technologies. Much depends upon where the study originates, but wind and nuclear tend to be comparable in terms of energy cost.

For example:
g/kWh CO2 Japan
coal 975
gas thermal 608
gas combined cycle 519
solar photovoltaic 53
wind 29
nuclear 22
hydro 11

Sweden
Coal 980
gas thermal 1170 (peak load reserve)
gas combined cycle 450
solar photovoltaic 50
wind 5.5
nuclear 6
hydro 3

Finland
Coal 894
gas thermal
gas combined cycle 472
solar photovoltaic 95
wind 14
nuclear 10 - 26
hydro -

http://world-nuclear.org/info/inf11.html
But I'm sure Biff won't like that either.

 

[Penners]

I must say I find it utterly incredible that nuclear energy could have the same carbon footprint as hydro or wind. The construction and decommissioning costs (which are really the only significant carbon-emission factors for all three, although mining and enrichment is also a factor in nuclear) are so massively different as to be from opposing planets (if not fairyland).

 

[MdB]

I must say I find it utterly incredible that nuclear energy could have the same carbon footprint as hydro or wind. The construction and decommissioning costs (which are really the only significant carbon-emission factors for all three) are so massively different as to be from opposing planets (if not fairyland).

But so is the amount of electricity that can be generated. Nuclear is typically 1GW per reactor which is sustainable output power. The largest wind turbine is 6MW peak so the average will be less.

 

[Penners]

Fair enough, MdB, but a wind turbine is basically a big pole with a propeller-driven generator on top. Compare 166.6 of those with a nuclear power plant, plus the mining and fuel-enrichment facilities.

I still can't see a level playing field.

 

[MdB]

My guess is that you will need well over a thousand average wind turbines to produce the same electricity as an average reactor. I do agree however that the wind turbines would be preferable. If only we needed 1GW to run the country... The actual figure is approx 50GW or 50000 wind turbines or 1 per every 5 square km across the entire UK.

 

[Flyfisher]

That's an interesting way of visualising the problems we're facing. But, presumably, not even that number of turbines would prevent the lights going out when the winds are low.

I suspect we only really have the luxury of such debates because, even after recent price hikes, we're lucky enough to be living in a period of essentially unlimited energy, whether for our cars, home, cities or industry. I wonder how the debate would develop if real rationing becomes a necessity? Nothing like sitting in the dark or living with petrol coupons to reveal real public opinion.

As I understand things, the UK has sufficient coal to be self-sufficient for hundreds of years and I notice that the government has already started to use the term 'clean coal' even though the technology is yet to be fully proven (I believe). Green or not, I doubt that any government would survive widespread power cuts while we still have coal in the ground.

 

[middi]

I was wondering, if the energy situation is in dire straits and obviously going to get REALLY bad in the future ( man eat man type of thing), shouldn't we be thinking of training our body's to extrude enough methane from our backsides to become self sufficient.

Evolution in the right direction that's what I say. ( I only thought of that because some of our thinking regarding the Energy situation appears to generate from that direction)

 

[Moo]

A patch of jerusalem artichokes in every garden should do the trick.

 

[biffvernon]

Its a professional magazine that deals with all energy technologies fairly. That's not fairyland.

But you haven't said where in TCE Magazine. Quote source?

 

[Penners]

A patch of jerusalem artichokes in every garden should do the trick.

:lol: :lol:
I think you missed off the "f".

 

[middi]

.... :lol: :lol: :lol: ....( sod it, i missed that one)

 

[Flyfisher]

Sorry to be pedantic but, even if we were to quickly evolve a ruminant digestive system, I believe the majority of methane would be emitted via belching - marginally more acceptable, perhaps?