the future

in message <[email hidden]>, James

Annan (') said:

Simon Brooke said:

It doesn't matter /how/ you convert the energy, laddie, it
matters /how/ /much/ energy there is to convert. Blue-green algae
can't magic energy out of nowhere. Solar energy, raw, unconverted, as
it comes from the sun, amounts to about 1500 watts per m^2 under ideal
conditions in the most favourable places on the planet. If your blue
green algae can achieve 100% conversion - and in the process can
extract every last joule of energy from every gramme of pigshit on the
planet - it still won't boil kettles for the world's population.

Do the maths!

You've already been corrected on the "energy from pigshit" error
several times. Don't repeat it too many times unless you want everyone
to think you're a moron :-)

The blue green algae have, according to the paper, two inputs: the sun
and the [censored]. I was merely suggesting they might maximise the energy
potential of both.

Quoted message said:

The world's entire population does not actually want to boil kettles
simultaneously - a vague google suggests a typical UK *household* (not
person) only consumes a few hundred watts of electricity on average,
and much of the world is of course far lower.

Of electricity. In Japan, of course, your peas are flown in from Thailand
rather than Kenya, but the effect is the same; the planes don't fly on
electricity. Similarly, the cars and trains that most people (not
including yourself) commute to work in, don't run on electricity; and
most people's central heating (and/or air conditioning, for those of you
in warmer climes) does not run on electricity. But they all run on
energy in some form, and if people are suggesting that when the oil runs
out we're going to be able to replace it all with solar power, then that
is a heck of a lot of solar power.

In simple terms: the energy consumption on the electricity meter in your
hall is not the sum total of your energy cost to the economy.

So we do one of two things: we pave substantial areas of the planet - all
we don't need to grow the food we need to feed a still rapidly expanding
population - with solar collectors of some sort, which if they are
effectively taking heat out of the system and converting it must
inevitably seriously alter the convection effects which drive our
weather patterns; or else we put large focussed solar reflectors up in
orbit, in which case we can expect some fairly horrible accidents from
time to time as random bits of debris knock the reflectors out of
alignment and send highly focussed energy beams on an unpredictable
dance across the landscape (or we find some other, non-solar, technical
fix which involves some other downside).

I'm not saying technical fix is impossible. All I'm saying is that if
there is to be an effective technical fix, the time to start doing
something about it is now; and that unless the fix is using radically
less energy (which we actually could do, relatively easily) then the
consequences are going to be pretty unpleasant, on way or another.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; IE 3 is dead, but Netscape 4 still shambles about the earth,
;; wreaking a horrific vengeance upon the living
;; anonymous

in message <[email hidden]>, David

Martin (') said:

Simon Brooke said:

in message <[email hidden]>, Jim Ley

(') said:

On Sat, 28 Jan 2006 20:32:38 +0000, Simon Brooke
<[email hidden]> wrote:

>Like I said, we /could/ solar panel over the Sahara desert.

Can you please start reading the posts, Nowhere were solar panels
mentioned, the fuel source was blue-green algae..

It doesn't matter /how/ you convert the energy, laddie, it
matters /how/ /much/ energy there is to convert. Blue-green algae
can't magic energy out of nowhere. Solar energy, raw, unconverted, as
it comes from the sun, amounts to about 1500 watts per m^2 under ideal
conditions in the most favourable places on the planet. If your blue
green algae can achieve 100% conversion - and in the process can
extract every last joule of energy from every gramme of pigshit on the
planet - it still won't boil kettles for the world's population.

Do the maths!

A kettle takes 3kw, or requires all the sunshine for 2m2 of the earths
surface.

At the equator. The amount of sunlight which impinges on the surface at
any particular degree of latitude is a trig function of that latitude,
which is /why/ the poles are cooler than the equator. Furthermore, of
course, much of the surface of the planet is not suitable for panelling;
more than two thirds of it is water. Furthermore, if you convert the
impinging energy into electricity rather than heating the environment as
it otherwise would, you locally cool the environment, and if you do this
in large enough blocks you change the weather. Furthermore, people need
food to eat, so you can't [censored]-nilly pave over arable land. When you
come down to it, pretty much the only places you /can/ pave over are the
roofs of buildings and deserts, and even that has consequences.

Quoted message said:

No problem then if everyone wants to boil a kettle. Even the
most densely populated area doesn't get anywhere close to an order of
magnitude of that. (ie less than 1 person per 20m2.)

So the answer is that it would boil kettles for the worlds population.

If you paved the whole planet, yes. I wasn't proposing anything that
radical - just an area a bit bigger than Europe.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

For office use only. Please do not write or type below this line.

Simon Brooke said:

So we do one of two things: we pave substantial areas of the planet - all
we don't need to grow the food we need to feed a still rapidly expanding
population - with solar collectors of some sort, which if they are
effectively taking heat out of the system and converting it must
inevitably seriously alter the convection effects which drive our
weather patterns; or else we put large focussed solar reflectors up in
orbit, in which case we can expect some fairly horrible accidents from
time to time as random bits of debris knock the reflectors out of
alignment and send highly focussed energy beams on an unpredictable
dance across the landscape (or we find some other, non-solar, technical
fix which involves some other downside).

I think it's time you checked your calculation. In particular, the
Sahara seems to be about 9 million km^2 = 9000 billion m^2, not 4.5
billion m^2.

Quoted message said:

I'm not saying technical fix is impossible. All I'm saying is that if
there is to be an effective technical fix, the time to start doing
something about it is now; and that unless the fix is using radically
less energy (which we actually could do, relatively easily) then the
consequences are going to be pretty unpleasant, on way or another.

Well you started out by making some absurd comments about how desperate
things would be in 2050, and went downhill from there :-)

James
--
James Annan
see web pages for email
http://www.ne.jp/asahi/julesandjames/home/
http://julesandjames.blogspot.com/

Simon Brooke wrote on Sunday 29 January 2006 10:31:

Quoted message said:

I'm not saying technical fix is impossible. All I'm saying is that if
there is to be an effective technical fix, the time to start doing
something about it is now; and that unless the fix is using radically
less energy (which we actually could do, relatively easily) then the
consequences are going to be pretty unpleasant, on way or another.

I'd say the time to start doing something about it was around 1900. My
feeling is that it's all too little, too late, and of course, in a
capitalist economy, where short-term thinking reigns supreme, there is
no chance of any solution before the ordure hits the fan.

I think that the human race has lost the race.

--
Regards
Alex
The From address above is a spam-trap.
The Reply-To address is valid

Simon Brooke said:

Quoted message said:

You've already been corrected on the "energy from pigshit" error
several times. Don't repeat it too many times unless you want everyone
to think you're a moron :-)

The blue green algae have, according to the paper, two inputs: the sun
and the [censored]. I was merely suggesting they might maximise the energy
potential of both.

Umm - ITYF that the algae are taking the sunlight and storing that
energy by converting the pigshit. That creates both enthalpic and
entropic energy stores.

The criteria is not how much energy can be extracted from pigshit (cf
discharged battery) but how much can be stored in it.

...d

Alex Potter said:

I'd say the time to start doing something about it was around 1900. My
feeling is that it's all too little, too late, and of course, in a
capitalist economy, where short-term thinking reigns supreme, there is
no chance of any solution before the ordure hits the fan.

I think that the human race has lost the race.

We just have to go back a few years to nuclear and coal power if nothing
else. The US uses 100 quads a year of energy and coal reserves are
estimated at 100,000 quads - about 300 years reserves. Then there are
the massive untapped reserves in methane hydrate deposits all over the
planet. They just need the access technologies and clean burn technology.

When its needed it will happen in just the same way that the North Sea
technology was developed very quickly once it became needed in the 80's
and 15 years later they were drilling, finding and producing oil in
several km of water in e.g. the Gulf of Mexico.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

in message <[email hidden]>, Alex Potter

(') said:

Simon Brooke wrote on Sunday 29 January 2006 10:31:

Quoted message said:

I'm not saying technical fix is impossible. All I'm saying is that if
there is to be an effective technical fix, the time to start doing
something about it is now; and that unless the fix is using radically
less energy (which we actually could do, relatively easily) then the
consequences are going to be pretty unpleasant, on way or another.

I'd say the time to start doing something about it was around 1900. My
feeling is that it's all too little, too late, and of course, in a
capitalist economy, where short-term thinking reigns supreme, there is
no chance of any solution before the ordure hits the fan.

I think that the human race has lost the race.

Just so.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
; ... of course nothing said here will be taken notice of by
; the W3C. The official place to be ignored is on www-style or
; www-html. -- George Lund

John Pitcock (nospam) said:

Today's Times:
http://www.timesonline.co.uk/article/0,,2-2011758,00.html

"Transport experts have seen , and it's got pedals"

John Pitcock

An interesting assumption here is that people want to travel. And while
I am quite happy to go cycling in France or even on Wolfe Island (
local area ) I have no desire to travel several kilometres to get a
loaf of bread or a bottle of wine. I suspect that the report may be
making the mistake of thinking about travel rather than access to
services.

A simple return to smaller neighbourhoods with relatively complete
services immediately reduces travel needs drastically even if one must
commute for work. Where I live in a small Canadian city I am within a
roughly one km radius of grocery stores, sports fields, theatres,
farmers' market, golf course, restarurants, bars, and misc stores. I
seldom need to travel long distances for normal needs. The death of a
few big box stores, due to increased consumer travel costs might make a
huge difference in peoples need to travel.
John Kane, Kingston ON Canada

"John_Kane" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

John Pitcock (nospam) said:

Today's Times:
http://www.timesonline.co.uk/article/0,,2-2011758,00.html

"Transport experts have seen , and it's got pedals"

John Pitcock

An interesting assumption here is that people want to travel. And while
I am quite happy to go cycling in France or even on Wolfe Island (
local area ) I have no desire to travel several kilometres to get a
loaf of bread or a bottle of wine. I suspect that the report may be
making the mistake of thinking about travel rather than access to
services.

I am quite happy to cycle several kilometres to get a loaf of bread etc.
indeed, unless I bake it myself, I have to travel several kilometres... and
even if I bake it myself, I still travel several kilometres for the
ingredients. By bike is fine :-)

Cheers, helen s

Simon Brooke said:

Quoted message said:

Only because we happened to have lots of it at the time. Other rail
industries used local fuels - wood, particularly in the US, and sugar
cain husks in the West Indies, which are (can be) renewable resources.

It doesn't take many train journeys to fell a forest. You couldn't run
the current London commuter network on wood-fuelled steam trains, even
if you planted every arable hectare of Britain with quick growing trees.

How do you work that out?

BOTE calculation: you can get 10 MW from a locally sustainable
willow-fired (steam turbine) power station (a quick Google suggests).

To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
using devices of a very pessimistic 10% efficiency requires ~10 MW of power.

Yes, there is an economy of scale in the power station generation, I've
neglected hills, etc. But the figures are in the same ballpark.

R.

Richard said:

To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
using devices of a very pessimistic 10% efficiency requires ~10 MW of
power.

So how on earth did you work that one out? From your parameters I can
see how to work out the energy needed to accelerate them to 10m/s but
nothing at all about the power to keep them moving at that speed for any
given time.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Tony Raven said:

Richard said:

To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
using devices of a very pessimistic 10% efficiency requires ~10 MW of
power.

So how on earth did you work that one out? From your parameters I can
see how to work out the energy needed to accelerate them to 10m/s but
nothing at all about the power to keep them moving at that speed for any
given time.

BOTE 1/2mv^2. It's a zeroth order calculation, I'll happily admit it.
Having said that, the energy needed to keep something rolling on
metal rails is very little compared to that needed to get it rolling in
the first place; railwaymen used to manhandle trucks around yards with
nowt more than a big stick or two. Someone with more time on their
hands can start adding the first order bits. :-)

R.

Richard said:

Tony Raven said:

Richard said:

To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
using devices of a very pessimistic 10% efficiency requires ~10 MW of
power.

So how on earth did you work that one out? From your parameters I can
see how to work out the energy needed to accelerate them to 10m/s but
nothing at all about the power to keep them moving at that speed for
any given time.

BOTE 1/2mv^2. It's a zeroth order calculation, I'll happily admit it.
Having said that, the energy needed to keep something rolling on metal
rails is very little compared to that needed to get it rolling in the
first place; railwaymen used to manhandle trucks around yards with nowt
more than a big stick or two. Someone with more time on their hands can
start adding the first order bits. :-)

Your calculation is not even zero order. You have calculated the power
to accelerate all those people to 10m/s over a period of one hour i.e.
it takes an hour to get them up to speed. Unlike trucks round a yard,
maintaining a speed of 10m/s will also require power because of the air
resistance even if there is no rolling resistance or slopes to deal
with. IOW your calculation is meaningless.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Tony Raven said:

Richard said:

Tony Raven said:

Richard wrote:

>
> To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
> using devices of a very pessimistic 10% efficiency requires ~10 MW
> of power.
>

So how on earth did you work that one out? From your parameters I
can see how to work out the energy needed to accelerate them to 10m/s
but nothing at all about the power to keep them moving at that speed
for any given time.

BOTE 1/2mv^2. It's a zeroth order calculation, I'll happily admit
it. Having said that, the energy needed to keep something rolling on
metal rails is very little compared to that needed to get it rolling
in the first place; railwaymen used to manhandle trucks around yards
with nowt more than a big stick or two. Someone with more time on
their hands can start adding the first order bits. :-)

Your calculation is not even zero order. You have calculated the power
to accelerate all those people to 10m/s over a period of one hour i.e.
it takes an hour to get them up to speed.

Correct. Of course in the real case, it'll stop and start and coast
and climb hills and play waltzing matilda. The idea of a zeroth order
estimate is to find the right ballpark. The OP, whose comment has been
cut, asserted that it would be impossible to power London's commuter
trains with wood-burning locomotives even if the entire arable landmass
of the UK was planted with trees (or words to that effect). I've
pointed out that his assertion requires supporting evidence, since the
ballpark BOTEC suggests otherwise; the point of a BOTEC is to decide if
it's worth spending the time improving the calculation or not. Feel
free to improve the physics and see how the numbers change.

Quoted message said:

Unlike trucks round a yard,
maintaining a speed of 10m/s will also require power because of the air
resistance

Of course it will. Here's a BOTEC to see how much power is needed; a
100 ton train with a 10 square metre frontal area travelling
(freewheeling) at 10 m/s over level ground, neglecting any form of
rolling resistance. Wind resistance deceleration ~ Cf rho A v^2 / m,
where Cf is the cofficient of drag and rho is the air density ~ Cf * 10
* 1.2 * 10^2 / 100E3, ~ 0.01 Cf m/s^2. I think there's a factor of two
in there somewhere, but I can't remember where; anyhow, I've no idea
what the Cf for a train is, but I'll guestimate 1 within a factor of two
for the sake of argument; that's an overall resistance deceleration of
0.01 m/s^2. So our train is acted on by ~1000 N of retarding force, or
if you prefer, requires 10 kW additional energy to maintain a constant
speed, or, if you prefer, will take around 15 minutes or 5 miles to stop
when freewheeling, to zeroth order calculation. Hardly important when
it's compared to the MWs or more actually getting the thing going in the
first place, which is what I said before.

R.

Richard said:

Quoted message said:

Quoted message said:

>>
>> To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
>> using devices of a very pessimistic 10% efficiency requires ~10 MW
>> of power.
>>

Of course it will. Here's a BOTEC to see how much power is needed; a
100 ton train with a 10 square metre frontal area travelling
(freewheeling) at 10 m/s over level ground, neglecting any form of
rolling resistance. Wind resistance deceleration ~ Cf rho A v^2 / m,
where Cf is the cofficient of drag and rho is the air density ~ Cf * 10
* 1.2 * 10^2 / 100E3, ~ 0.01 Cf m/s^2. I think there's a factor of two
in there somewhere, but I can't remember where; anyhow, I've no idea
what the Cf for a train is, but I'll guestimate 1 within a factor of two
for the sake of argument; that's an overall resistance deceleration of
0.01 m/s^2. So our train is acted on by ~1000 N of retarding force, or
if you prefer, requires 10 kW additional energy to maintain a constant
speed, or, if you prefer, will take around 15 minutes or 5 miles to stop
when freewheeling, to zeroth order calculation. Hardly important when
it's compared to the MWs or more actually getting the thing going in the
first place, which is what I said before.

A quick google suggests that the London Underground used just over 1TWh
in 2004 - assuming I've got my sums right thats about 120MW continuous
(no idea what the peak would really be like) and I've no idea how that
breaks down to propulsion, heating lighting etc.

I also found this:
http://www.buildingtalk.com/news/mis/mis102.html
"Interestingly the escalators on London Underground use electricity in
the morning when they are running upwards, but regenerate almost as
much again in the evening."

Presumably this is down to peoples station being on the surface at
their home end and underground in the city. (on average, residents of
Primrose Hill need not write in :-)

Tim.

wafflycat said:

"John_Kane" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

John Pitcock (nospam) said:

Today's Times:
http://www.timesonline.co.uk/article/0,,2-2011758,00.html

"Transport experts have seen , and it's got pedals"

John Pitcock

An interesting assumption here is that people want to travel. And while
I am quite happy to go cycling in France or even on Wolfe Island (
local area ) I have no desire to travel several kilometres to get a
loaf of bread or a bottle of wine. I suspect that the report may be
making the mistake of thinking about travel rather than access to
services.

I am quite happy to cycle several kilometres to get a loaf of bread etc.
indeed, unless I bake it myself, I have to travel several kilometres... and
even if I bake it myself, I still travel several kilometres for the
ingredients. By bike is fine :-)

Cheers, helen s

Well yes, but you're one of these poor people who lives out in the
wilds of Norfolk and cannot be expected to understand the joys of urban
living with a depaneur on every corner and 24 hour pizza delivery 🙂 I
would never consider cycling several km for a loaf of bread. It is a
lot easier to bake it myself. When living in the country I would ride
30 km into town to pick up the 10 kg of flour though.

A real problem is the amount of car usage over relatively minor
distances in urban areas which cheap fuel and free auto-parking
encourages. I am permanently annoyed that I get to help pay for
people's _free_ parking at stores since part of my costs go to pay for
the maintanence of the grocery store parking lot etc. This, BTW, is
probably a bigger component in terms of maintanence costs in Canada
since we have to plough snow off the parking lot or contend with salt
damage in in-door parking.
John Kane, Kingston ON Canada

Quoted message said:

A quick google suggests that the London Underground used just over 1TWh
in 2004 - assuming I've got my sums right thats about 120MW continuous
(no idea what the peak would really be like) and I've no idea how that
breaks down to propulsion, heating lighting etc.

Until 2002 London Underground had its own 180MW Lots Road Power Station.
That has now been shut down and its power needs, which peak at 200MW
are supplied by British Energy, 75% of it coming from Dungeness and
Sizewell.
http://en.wikipedia.org/wiki/Lots_Road_power_station

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Quoted message said:

Richard said:

Quoted message said:

>>>To move 1,000,000 commuters weighing 70 kg each at 10 m/s for 1 hour
>>>using devices of a very pessimistic 10% efficiency requires ~10 MW
>>>of power.
>>>

Of course it will. Here's a BOTEC to see how much power is needed; a
100 ton train with a 10 square metre frontal area travelling
(freewheeling) at 10 m/s over level ground, neglecting any form of
rolling resistance. Wind resistance deceleration ~ Cf rho A v^2 / m,
where Cf is the cofficient of drag and rho is the air density ~ Cf * 10
* 1.2 * 10^2 / 100E3, ~ 0.01 Cf m/s^2. I think there's a factor of two
in there somewhere, but I can't remember where; anyhow, I've no idea
what the Cf for a train is, but I'll guestimate 1 within a factor of two
for the sake of argument; that's an overall resistance deceleration of
0.01 m/s^2. So our train is acted on by ~1000 N of retarding force, or
if you prefer, requires 10 kW additional energy to maintain a constant
speed, or, if you prefer, will take around 15 minutes or 5 miles to stop
when freewheeling, to zeroth order calculation. Hardly important when
it's compared to the MWs or more actually getting the thing going in the
first place, which is what I said before.

A quick google suggests that the London Underground used just over 1TWh
in 2004 - assuming I've got my sums right thats about 120MW continuous

Coo. Not bad, then, my 10 MW BOTE - only out by an order of magnitude,
which ain't bad for the [censored] of my calcs. :-)

R.

Richard said:

Having said that, the energy needed to keep something rolling on
metal rails is very little compared to that needed to get it rolling in
the first place; railwaymen used to manhandle trucks around yards with
nowt more than a big stick or two.

They still do, and I did it myself yesterday. Choo Choo!!

"Bob"
--

Email address is spam trapped, to reply directly remove the beverage.