Re: why would you NOT have an active roof
>Why would one not want to have a PV roof, if its cost effective,
It isn't - well it is if you have a little old lady down the road paying 2x as much to subsidise your feed-in
>Cost is the measure we use as an economy in the supply demand economy we live in,
In which case nobody would have solar and we would just buy cheap gas from Russia
No need to worry about what happens if Russia turns off the supply or the price goes up - that's next quarter's problem.
>and the world connected up, then sun in one place could be exported to power some where else.
Look at the cost of the new grid Germany is having to build to move French nuclear power to Bavaria now that they are closing their reactors. Now imagine running a cable 100x bigger from the Sahara to Scandanavia.
>may be PV is not the best option in the dessert, may be the solar towers like in Spain are the way
In the desert probably tents and a turbine tower.
>A few pump storage schemes in the mountains of the world, a few convert water to Hydrogen in other
The cost of the loan to pay for Dynorwig makes its electricity more expensive than the grid - even if the input power is free. There are also limited places you can put a pumped storage scheme and they aren't where the demand for the power is. Most cities aren't in the mountains.
>its not that hard.
It's very hard
>lets leave the gas, oil, coal as a chemical resource we can use, not 'just' oxidise them to carbon dioxide.
Renewables require highly reactive peaking plants - small stations you can turn on and off quickly, which basically equals gas turbines. Ever wind farm means also buying a lot of jet engines.