MPG: BLT Vs Petrol

mr_eddy

Ok so not sure if anyone watched on TV (Bang Goes the Theory) but they did an experiment to see how fuel effecient a person is compared to the internal combustion engine.

The experiment was simple a moped was drained of fuel and 1000 calories worth of petrol was added into the empty tank, it looked like about 300ml. Secondly the presenter ate a cooked breakfast totalling 1000 calories.

To make the challenge even the bicycles panniers were weighted down until the whole lot weighed 100 kg to match the kerb weight of the moped.

They each then set of at a moderate pace with the presenter wearing a face mask that measures how many calories are burned.

The result, the moped managed a impressive 140 mpg and the bicycle a frankly unbelievable 575 mpg!

When you bear in mind he was using a hybrid with quite wide tyres that were pretty squidgy due to the extra weight then I reckon under normal circumstances that 575 would be a lot higher.

Check it out at bbc.co.uk/bang

sfichele

Not seen it yet but the numbers seem totally believable. Here's a python script, that gives almost the same answer:

caloriesPerLitre = 3768
litresPerGallon = 4.54
caloriesPerGallon = caloriesPerLitre * litresPerGallon;
mopedMPG = 140;
bikeCal = 30

print "MOPED: has", caloriesPerGallon, "in a gallon"
print "MOPED: used", caloriesPerGallon/mopedMPG, "calories Per Mile @", mopedMPG, "mpg"
print "BIKE: calories per mile:", bikeCal
print "BIKE: mpg", caloriesPerGallon/bikeCal

And here's the result using 30 calories per mile if you are on a bike:

MOPED: has 17106.72 in a gallon
MOPED: used 122.190857143 calories Per Mile @ 140 mpg
BIKE: calories per mile: 30
BIKE: mpg 570.224

RideOnTime

Much rather have a BLT...
Petrol leaves a taste in the mouth...

rake

apparently, and electric bicycle has a lower carbon footprint than a normal bike, the extra food is shipped around the world, that includes charging the bike from the grid too. something like 25% efficiency in humans, calories eaten v calories propelling bike.

zippypablo

RideOnTime wrote:

Much rather have a BLT...
Petrol leaves a taste in the mouth...

Wirral_paul

Well i had no breakfast this morning therefore consumed 0 calories. I did a brisk 20 mile ride (18.8mph ave with 500ft climbing) before work - so what was my fuel economy?? :?:

Kinda knackers up the results really, given that the presenter presumably wasnt at death's door due to lack of energy before eating!! I'd suggest the results are quite meaningless - i'd feel comfortable setting out for 2hrs without eating to be honest

bompington

Wirral_Paul wrote:

Well i had no breakfast this morning therefore consumed 0 calories. I did a brisk 20 mile ride (18.8mph ave with 500ft climbing) before work - so what was my fuel economy?? :?:

Kinda knackers up the results really, given that the presenter presumably wasnt at death's door due to lack of energy before eating!! I'd suggest the results are quite meaningless - i'd feel comfortable setting out for 2hrs without eating to be honest

Yeah, and I haven't filled up the car since last week so I've now gone 120 miles without using any petrol at all!

schweiz

Wirral_Paul wrote:

Well i had no breakfast this morning therefore consumed 0 calories. I did a brisk 20 mile ride (18.8mph ave with 500ft climbing) before work - so what was my fuel economy?? :?:

Kinda knackers up the results really, given that the presenter presumably wasnt at death's door due to lack of energy before eating!! I'd suggest the results are quite meaningless - i'd feel comfortable setting out for 2hrs without eating to be honest

The existing fuel in the tank (moped or human) is irrelevent to the argument. The BLT was just to allow a visual comparison of food to 1000 calories worth of unleaded. The measurement of calories burnt was what was important. Whether those calories came from the BLT or what was already in the 'tank' doesn't matter. The point is that a cyclist can travel further on 1000 calories even when handicapped to match the gross weight of the scooter.

sfichele

^ and the simple calculation I posted demonstrates that. Its well known that a cyclist will use around 20-30 calories per mile, whereas the moped in this case was using 122 calories per mile. So the bike is between 4-6 times more efficient depending on speed.

rake

sfichele wrote:

^ and the simple calculation I posted demonstrates that. Its well known that a cyclist will use around 20-30 calories per mile, whereas the moped in this case was using 122 calories per mile. So the bike is between 4-6 times more efficient depending on speed.

but food uses more calories being shipped than it yields being eaten.

verylonglegs

Does the calories from the meat take into account the calories required in foodstuffs to produce that meat in the first place?

schweiz

rake wrote:

sfichele wrote:

^ and the simple calculation I posted demonstrates that. Its well known that a cyclist will use around 20-30 calories per mile, whereas the moped in this case was using 122 calories per mile. So the bike is between 4-6 times more efficient depending on speed.

but food uses more calories being shipped than it yields being eaten.

And drilling for crude oil, shipping it or pumping it on shore, refining it, transporting it to the petrol station will use a fair bit of energy too!

sfichele

+1 Its called Energy Return on Energy Invested, EROEI.
For middle east oil its around 30+, i.e you need energy from 1 barrel of oil to extract 30+ barrels and get it to a car's tank. But there are other forms of oil production that have really low returns making them really inefficient

rake

and then they use them to transport food. also the food is usually farmed with said fuels.

Jez mon

At the end of the day, the Petrol is inherently less efficient at point of use AND requires a fair bit of energy to extract/refine/transport. All the ingredients for a BLT can be grown in a (admittedly large) garden using a greenhouse, or environmentally friendly heating like British Sugar do! Alternately the human body can be fed different fuel.

rake

electric bicycle beats both (commercially grown food)

centimani

Another way of looking at it...
One of my routes takes in a nice cafe. On a 50-60 ish mile ride, i stop for breakfast, stop for a can of drink and maybe a Mars Bar, then stop for some chips perhaps or a coffee and some cake....total cost last summer was around £6. Thats a gallon of petrol, the same amount to drive as ive just eaten. I didnt save a penny. But it was far more enjoyable.