Food miles

Does local equal better? Not always...

• British tomato growers emit 2.4 metric tons of carbon dioxide for each ton of tomatoes grown compared to 0.6 tons of carbon dioxide for each ton of Spanish tomatoes
• cold storage of British apples produced more carbon dioxide than shipping New Zealand apples by sea to London. 
• U.K. dairy farmers use twice as much energy to produce a metric ton of milk solids than do New Zealand farmers. 
• Kenyan cut rose growers emit 6 metric tons of carbon dioxide per 12,000 roses compared to the 35 tons of carbon dioxide emitted by their Dutch competitors.

From:  The Food Miles Mistake

My view: a carbon tax or cap and trade would sort this out; the assumption that local is better is probably counter-productive.

PS: Amory Lovins is working with Wal-Mart to double the mpg of big trucks like the one pictured above.

Cell count

3D rendered image of translucent cells dividing

Our bodies contain approximately 10 quadrillion cells (10 x 10^15). In addition, we are host to a further 100 quadrillion bacterial cells.

Each of our cells (well, over 99.99% of them at least) contain a string of DNA almost 2 metres long with 3.2 billion base pairs (where a base is one of adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T)).

Each cell typically contains twenty thousand different types of protein and a minimum of 100 million protein molecules.

From: Bill Bryson: A Short History of Nearly Everything

Oil Sands

 Fort McMurray Oil Sands, Canada

From Wikipedia:

However, the world's largest [oil sands] deposits occur in two countries: Canada and Venezuela, each of which has oil sand reserves approximately equal to the world's total reserves of conventional crude oil.

In numbers:

Conventional crude reserves: 1.75 trillion barrels
Canadian + Venezuelan oil sand reserves: 3.6 trillion barrels

It isn't clear if these reserves are those at a given price, eg today's $90 per barrel, or not.

Nissan Leaf calculations

Wikipedia: Under its five-cycle testing, the United States Environmental Protection Agency found the Leaf's energy consumption to be 765 kJ/km (34 kWh/100 miles)

This is 340Wh/mile. A 1x1m solar panel in Aberystwyth yields about 200  kWh/year at 20% efficiency (200 / 0.34 = 588 miles). So 6,000 miles a year in a Nissan Leaf would require about 10m² of solar panels.

The SAP calculator gives a 2.4kWp system for 2,000 kWh/year.  At Solarbuzz prices of €3.09 per watt this is about €7.4k for modules, say €14.8k installed. This is about £12.5k at today's exchange rate. With a FIT of 41p/kWh this is an approx 15 year payback. Solarbuzz also shows cheapest module price in Germany of €1.56. Again doubling for installation, this would give about a 7.5 year payback.

DECC's 2050 Energy Calculator

DECC have recently published an on line calculator for various energy scenarios up to the year 2050 (thanks Susanna for the link!). A friend of mine said they couldn't get onshore wind to be a significant component of any scenario. I played around with it a bit and by choosing the minimum demand scenario (1000 TWh per year) and the 'Heroic effort' wind numbers, I get onshore wind at 13% and offshore wind at 43%. Not insignificant.

DECC 2050 Pathway

Onshore wind 130 TWh/yr:

Offshore wind 430 TWh/yr:

Aberystwyth at 633 mph?

What's this? A new land speed record? No, it's speed at the circumference of the earth as it rotates once every 24 hours.

The circumference of the earth at the equator is approx 24,000 miles giving a speed of 1000 miles at the equator. Using a cosine equation and putting in Aberystwyth's latitude of 52.4N we get 633 mph.

Equation:

circumference = 2 x Pi x R x Cos(Pi x 52.4/180) where R = radius of the earth = 3963 miles

Source: Ask A Scientist

World's biggest truck?

Liebherr T 282B mining truck

This fine example of German engineering, the world’s largest earth-hauling dump truck, has an empty weight of 203 metric tons, a load capacity of 365 tons, and a wheelbase of 22 feet.  It’s powered by a 90-liter diesel engine that puts out 3,650hp.  The air-conditioned cabin sits eighteen feet above the ground.

And the fuel tank holds 1600 - 2000 gallons.

Source: The Munchkin Wrangler