Relevant statistics:
You don't need a university degree or a computer model to
establish the rate of increase of our pollution of the atmosphere with carbon, or to quantify the
astounding potential for solar power. It can all be worked
out by simple arithmetic from known facts. Below is a list of relevant values which should enable
anyone to repeat my calculations.
weight fraction of carbon in
carbon dioxide = 12/(12+32)
density of carbon
= 2266 kg/m3
earth area
= 5.101e14 m2
land area
= 1.49e14 m2
mass of atmosphere
= 5.27e18 kgs
population
= 6000e6
co2molefraction
= 360/1e6 {fraction by volume of CO2 currently in the atmosphere}
secs per year
= 60*60*24*365.25
energy per kg of carbon = 33 Mega joules
110 gms of carbon produces 1KWH (=3.6 Mega joules) when burnt
atmospheric carbon per square metre of land
= 3.5 kg
atmospheric carbon per square metre of the planet
= 1.0 kg
depth of atmospheric carbon if it was solid graphite on the ground
= 0.7mm
land area per person
= square of 160 metres side
current atmospheric carbon per person = 130 metric tons
Generation capacity of world PV production in 1997 was 130 Mega watts.
This IS increasing EXPONENTIALLY with a typical three year doubling period
Existing technologies
for Photovoltaics:
Initial Cost of PV plant in pounds ~= PV Production
capability in watts peak per year.
Depending on your global position, the mean energy production of a PV array
is typically between 10 and 30% (averaged night and day, summer and winter) of its quoted peak power.
It is estimated that between 2010 and 2020 most
office buildings in the UK will be PV clad
In the USA there is a ‘Million Solar Homes’ project.
The EEC is setting out a ½ Million
PV systems target.
In the UK we have a rather pathetic 100 Homes PV project