Red Blood Cells

How many red blood cells does the body produce an hour? Hundreds? Thousands? According to Wikipedia, the number is 2.4 million per second! I remember learning at school that red blood cells are made in bone marrow. But I don't remember how they get into the blood stream? Further research required :)

Red blood cells circulate the body every 20 60 seconds. After 100 to 120 days of existence they die (presumably at the same rate of 2.4 million per second) and are disassembled by microphages, who recycle the components. Amazing!

[Edit: updated circulation time: How long does it take for blood to circulate the body? It takes one minute for blood to circulate from the heart, all around the body, and back to the heart again.]

[Edit 2: The average healthy adult has 4.5 to 5.5 litres of blood... this is about 7% of a person's total body weight.]

[Edit 3: Red blood cell (RBC) count: 3.93 to 5.69 million cells per cubic millimeter (million/mm3) ]

Supernovae

Crab Nebula, product of the Supernova 1054

Sometimes stars at the end of their life explode, otherwise known as as a supernova. The average galaxy contains 100 billion stars and would experience a supernova about once a century.

So how many supernovae could you see stargazing on an average evening? Zero? It turns out that there are so many bazillions of galaxies out there that just in a thumbnail portion of the sky you would see 10 supernovae a night. Incredible!

- from War of the Worldviews (Chopra & Mlodinow) p61.

Nant-y-Moch revisited

OK, let's revisit the Nant-y-Moch wind farm numbers but restrict ourselves to kWh as the unit of energy and days for the unit of time.

Total UK electricity consumption in 2009 worked out at 15.6 kWh per person per day.

SSE, the wind farm developers, are claiming average production of 837,000 kWh per day.

This is equivalent to 53,700 people's daily usage. Or about 75% of the population of Ceredigion.

[Note: one kWh is the energy consumed by a 1kW 2-bar fire running for one hour]

Nant-y-Moch Wind Farm

According to SSE, the developers of the Nant-y-Moch wind farm, the annual energy output would provide for 65,000 homes (at 4.7MWh per household per year). This equates to 305 GWh/yr.

• http://www.nantymochwindfarm.com/the_facts.html

Annual UK per capita electricity consumption (not just household but shops, factories, street lights etc) was 5,692 kWh in 2009. Therefore Nant-y-Moch would provide the TOTAL electricity consumption for 53.6k people. Or nearly one in a thousand of the UK population. Just one wind farm!

Now US says solar PV to be cheaper than fossil fuels by 2020

RE < C? (renewable energy less than the price of coal?)

US Energy secretary "Chu began by making several observations about the US energy industry as it now stands. Onshore wind is already cheaper than new coal-fired energy"

And solar panel costs are falling amazingly rapidly...

Source: REneweconomy

UK Energy Consumption 2010

Drax, Yorkshire

Here it is: 114 kWh per person per day.

I was at a meeting the other day when someone said UK energy consumption was 125 kWh pp pday. That seemed high to me so I checked it out. My first attempt came in at 99 kWh pp pday. I then used BP's Statistical Review which shows UK 2010 consumption at 209.1 Mboe (Million barrels of oil equivalent). Using the excellent Wolfram site I converted this to TWh/year to GWh/day to kWh per person per day: 114.4.

This 114kWh per person per day is equivalent to a continuous usage of 4.77kW.

My personal electricity consumption is less than 2.75kWh per day or 0.115kW continuous.

Just testing

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