2.6. Solar http://www.ck12.org
Figure 6.12:Solar biomass, including all forms of biofuel, waste incineration, and food: 24 kWh/d per person.
Figure 6.13:Sunniness of Cambridge: the number of hours of sunshine per year, expressed as a fraction of the total
number of daylight hours.
Notes and further reading
...compensate for the tilt between the sun and the land. The latitude of Cambridge isθ= 52 ◦; the intensity of
midday sunlight is multiplied by cosθ' 0 .6. The precise factor depends on the time of year, and varies between
cos(θ+ 23 ◦) = 0 .26 and cos(θ− 23 ◦) = 0 .87.
In a typical UK location the sun shines during one third of daylight hours. The Highlands get 1100 h sunshine per
year – a sunniness of 25%. The best spots in Scotland get 1400 h per year – 32%. Cambridge: 1500±130 h per
year – 34%. South coast of England (the sunniest part of the UK): 1700 h per year – 39%. [2rqloc] Cambridge data
from [2szckw]. See also figure 6.16.