At first this seems like a fairly simple exercise, you need to boil water so you just need to work out how much energy is required to boil, say, a litre of water. Starting temperature is important but lets not get to pedantic, Google tells me 330.54 KJ, to convert that into watts we need a time, say 180 seconds to boil the kettle and voila we arrive at a figure 1836 Watts per second. This sounds about right for a 2000 Watt kettle.
So Watts = Amps x Volts, using data for a Suntellite 350W we have the following:-
Stated maximum power of 9.05 amps at 38.69 V gives us not surprisingly 350W, note the word maximum. Back to our kettle, we would require 2000/350 = 5.7 panels to make our coffee, providing all panels produce their stated 350 watts for 180 seconds. So there we have the answer, 6 panels, well actually no that is not the answer. In perfect conditions at midday with clear blue skies you would require 6 panels.
Look at the above graph and you will see how solar energy production varies during the day as well as the season. Solar panels are not just weather dependent they are also season dependent. So at midday on a perfectly clear and sunny day in summer we could use the 6 Solar panels and brew our cup of Java. However if you wanted your coffee at 6:00 am in the morning in summer on a clear day you are going to require around 24 Solar panels. Same time in winter sorry, no amount of panels will provide you with any power. In winter with 48 panels and with no fog, that is a clear sky, you might get your coffee around 08:00 am.
The calculations above are based on clear skies, throw in the vagaries of weather, the season and the simple question of “how many panels do I need to make a coffee?” cannot be answered. How can a modern economy operate with this type of power source? It is just utter madness!
Incompetence, greed and ignorance are the three pillars upon which modern society is built on.
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