Electric bikes?

On Wed, 9 Sep 2009 00:31:52 -0700 (PDT), NM
wrote:

Cycles are for those who enjoy the sport/exercise or for the
impoverished to get to and from work.

Or for people who work in cities, where bikes are typically faster
point to point. Or for people who care about the environment. Or for
people who live in places where parking is difficult. Or for people
who commute long distances and used mixed-mode. Or... well, you get
the idea.

Guy
--
http://www.chapmancentral.co.uk/urc | http://www.nohelmetlaw.org.uk/
"Nullius in Verba" - take no man's word for it.
- attr. Horace, chosen by John Evelyn for the Royal Society

Just zis Guy, you know? wrote:
On Wed, 9 Sep 2009 00:31:52 -0700 (PDT), NM
wrote:

Cycles are for those who enjoy the sport/exercise or for the
impoverished to get to and from work.

Or for people who work in cities, where bikes are typically faster
point to point. Or for people who care about the environment. Or for
people who live in places where parking is difficult. Or for people
who commute long distances and used mixed-mode. Or... well, you get
the idea.

Guy

Yeah but no but yeah but etc.
The big claim was that they didn't seem to have any impact on the
environment - it's the fairies wot makes the electricity in Santa's
workshop. They don't use any raw materials and there is never any waste.

Oh, and that somehow - they were fairly cheap, not mentioning the
possibility of forking out for a spare battery and that they are a sod
to try and pedal with no power available.

Other than that my LBS sells quite few.



--

Come to Dave & Boris - your cycle security experts.

In article ,
=?ISO-8859-1?Q?Andreas_Schulze_B=E4ing?= wrote:

I would agree that the environmental footprint of for example a
Pedelec is massively lower than that of a car - even an eco-posh
Prius.

Actually, a Prius has a very LARGE environmental footprint! The
coosts of extracting the materials to make it, constructing it and
disposing of it dominate the costs of using it.


Regards,
Nick Maclaren.

On Sep 9, 6:03*pm, Andreas Schulze Bäing
wrote:

An electric bike is completely emission free

Nothing is emission free - and a bicycle supported by an electric
motor certainly has a higher environmental footprint than a simple
steel-framed commuter bike.

Actually this is not so clear, if you consider the carbon footprint of
the food production necessary to power the cycling...

(not that this is the only consideration IMO)

James

James wrote:
On Sep 9, 6:03 pm, Andreas Schulze Bäing
wrote:

An electric bike is completely emission free
Nothing is emission free - and a bicycle supported by an electric
motor certainly has a higher environmental footprint than a simple
steel-framed commuter bike.

Actually this is not so clear, if you consider the carbon footprint of
the food production necessary to power the cycling...

I was planning to eat-to-live anyway!

BugBear

In message
James wrote:

On Sep 9, 6:03*pm, Andreas Schulze Bäing
wrote:

An electric bike is completely emission free

Nothing is emission free - and a bicycle supported by an electric
motor certainly has a higher environmental footprint than a simple
steel-framed commuter bike.

Actually this is not so clear, if you consider the carbon footprint of
the food production necessary to power the cycling...

(not that this is the only consideration IMO)

James

Yes there are many things that can be considered as contributing to the
overall costs but some of them dominate the calculations and are thus
worth comparing.

David MacKay has tried to make estimates of some of these key factors in
his book "Sustainable Energy - Without the Hot Air"

for example on page 256 he gives an estimate of a car as using 80
kWh/(100km) and a bicycle as using 2.4kWh/(100km).

see http://tinyurl.com/nsvvsq

Elsewhere in the book he has data for many different types of vehicle
and by converting the data into similar units it does allow different
modes of transport to be compared. For example he deals with food
production and consumption in terms of the energy usage per year per
person in the UK

Mike
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | caving, antibody engineer and
` || (_)/ (_) | \corn computer user"

On Wed, Sep 09 2009, Mike Clark wrote:

James wrote:

On Sep 9, 6:03*pm, Andreas Schulze Bäing
wrote:

An electric bike is completely emission free

Nothing is emission free - and a bicycle supported by an electric
motor certainly has a higher environmental footprint than a simple
steel-framed commuter bike.

Actually this is not so clear, if you consider the carbon footprint of
the food production necessary to power the cycling...

(not that this is the only consideration IMO)

James

Yes there are many things that can be considered as contributing to the
overall costs but some of them dominate the calculations and are thus
worth comparing.

David MacKay has tried to make estimates of some of these key factors in
his book "Sustainable Energy - Without the Hot Air"

for example on page 256 he gives an estimate of a car as using 80
kWh/(100km) and a bicycle as using 2.4kWh/(100km).

see http://tinyurl.com/nsvvsq

James may well be right wrt electric bikes (if their power consumption
is very low). Quoting MacKay (p80)

Walking has a CO2 footprint of 42 g/km; cycling, 30 g/km.
For comparison, driving an average car emits 183 g/km.

A 20kg electric bike[1] should surely do an order of magnitude less than
a 1.5 tonne car, though it will probably require some food-based energy
input from the rider too.

In the general case however, the "food-based CO2 footprint of cycling"
argument is dominated by the fact that if I wasn't cycle commuting I'd
be driving to the pool two or three times a week to pay for the
privilege of burning off the energy.

Brendan

[1] I also wonder why it wouldn't be much more efficient to have little
petrol motors -- how much loss is there in using fossil fuels to
generate electricity, transmit it, charge it into a battery with it and
then let it out again?
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
Tel: w +353-61-213147 f +353-61-202569 h +353-61-338562; Room F2-025 x 3147
http://www.ul.ie/sociology/brendan.halpin.html

Andreas Schulze Bäing wrote:
On 9 Sep, 06:07, Doug wrote:
Do you believe this?

"Using an electric bike is the best way there is to break the car
habit. The average car journey in Britain is 5 to 8 miles and every
day people in Britain make millions of small journeys to work or the
shops and back that could easily be non-polluting bike rides - during
rush-hour, a bike is twice as fast as a car - great if you hate jams!

In and around a densely built-up city centre a bike can be faster than
a car up to about 3 to 5 miles, depending on the city that you talk
about and the time of the day. Problem is that more and more people
live in suburbia or even further out in (what they believe is) the
countryside and... increasingly work in some business park or
industrial estate in suburbia. For these periphery-to-periphery
commutes it's very difficult to beat the car.

An electric bike is completely emission free

Nothing is emission free - and a bicycle supported by an electric
motor certainly has a higher environmental footprint than a simple
steel-framed commuter bike.

can be made genuinely
sustainable by purchasing electricity from a ‘green’ supplier, or
generating it via a roof-mounted windmill or solar panel. This will
enable the vehicles’ fossil fuel consumption to be zero."

I would agree that the environmental footprint of for example a
Pedelec is massively lower than that of a car - even an eco-posh
Prius.
The good thing about Pedelecs (bicycles supported up to 25 km/h by a
small electric motor) is that their energy consumption is really very
low. The electric motor has a power of up to 250 Watt, which is much
less than a car.
I tried one last week - and it's really a great innovation, though
I'll personally stick to my purely muscle driven bicycle.

Andreas

The main attraction of electric bikes as "powered transport" is that
they would mix well with muscle driven machines in the same way that gas
guzzling Chelsea tractors don't.

--
CTC Right to Ride Rep. for Richmond upon Thames

On 2009-09-09, Brendan Halpin wrote:
[...]
A 20kg electric bike[1] should surely do an order of magnitude less than
a 1.5 tonne car, though it will probably require some food-based energy
input from the rider too.

Yes, just think of the power. A car has about 100bhp which is around
75kW. A reasonably fit bicycle rider puts out only 0.15kW.

So although the engine in most cars is actually slightly more efficient
than the human body at converting chemicals into energy, it's consuming
energy at about 500 times the rate.

Of course the reason the car needs all that power is because it's so
massive, as you say. We also need them to go fast.

[...]
[1] I also wonder why it wouldn't be much more efficient to have little
petrol motors -- how much loss is there in using fossil fuels to
generate electricity, transmit it, charge it into a battery with it and
then let it out again?

Yes petrol motors are quite efficient, and you can have a huge range
from a small fuel tank, but they don't scale well down to such low
powers, so, as you say, you might need a battery to store energy and
then run the engine intermittently.

Or you can have a "pulse and glide" engine-- a 500cc 1 cylinder engine
but that only does 1rpm or so. I think this is more efficient than a
miniature 1cc engine running at 3000rpm (although that would be cute).

"Ben C" wrote in message
...
On 2009-09-09, Brendan Halpin wrote:
[...]
A 20kg electric bike[1] should surely do an order of magnitude less
than
a 1.5 tonne car, though it will probably require some food-based
energy
input from the rider too.

Yes, just think of the power. A car has about 100bhp which is around
75kW. A reasonably fit bicycle rider puts out only 0.15kW.

So although the engine in most cars is actually slightly more
efficient
than the human body at converting chemicals into energy, it's
consuming
energy at about 500 times the rate.

Of course the reason the car needs all that power is because it's so
massive, as you say. We also need them to go fast.

[...]
[1] I also wonder why it wouldn't be much more efficient to have
little
petrol motors -- how much loss is there in using fossil fuels to
generate electricity, transmit it, charge it into a battery with it
and
then let it out again?

Yes petrol motors are quite efficient, and you can have a huge range
from a small fuel tank, but they don't scale well down to such low
powers, so, as you say, you might need a battery to store energy and
then run the engine intermittently.

Used to be able to get little petrol motors (around 25cc???) that
attached over the front wheel of a pushbike, or could be built in to
the rear wheel. Don't know if they would be legal today..... but,
hey, that never worried cyclists.....