please do the math instead of posting random bullshit without any regard to whether or not it is true
i did
> A crude calculation (earthradius_equatorial^2 * pi * (1000 W/m^2) * 1 year in units(1) --- gosh, Unix is great!) suggests that the total solar energy falling on the earth is about 40000 * 10^20 joules per year.
... that's not a good approximation. There's someone who actually has done less crude math for maximum possible solar energy, at least for the UK: https://www.withouthotair.com/c6/page_38.shtml (though the HTML version is somewhat annoying because it's still paginated as if it were a book). Spoiler alert: it's roughly enough energy to cover total transportation energy demand, nowhere near total energy demand in the UK.
The farther north you go the more relevant technologies like wind energy and geothermal will become.
norway in particular gets almost all their electricity from hydroelectric plants https://www.statista.com/statistics/1025497/distribution-of-... but of course its transportation sector is still mostly fossil-powered
while i appreciate mackay's calculations a great deal, his estimates for very polar countries such as the uk are not generally applicable, and even for the uk are probably conditioned on overly pessimistic assumptions; he would undoubtedly agree if he were alive today
in particular, he assumed (reasonably) that 10%-efficient solar panels would be much cheaper than 20%-efficient ones, which would remain impractically expensive. but in fact most solar farms are being built with 21%-efficient panels because they're nearly as cheap as the 16%-efficient kind, and the 10%-efficient kind has been competed out of the market. so mackay's excellent calculations are all too low by more than a factor of 2, because one of his reasonable assumptions turned out to be wrong
but i do think it's plausible that without wind the uk would have to continue importing energy from abroad, as it has done since the 19th century, unless it goes nuclear. because mackay was aware his estimates for very polar countries such as the uk were not generally applicable, importing solar energy from abroad was in fact what he recommended in the chapter you linked but evidently didn't bother to read
Perhaps, but I see nothing in your post that actually corrects for effective solar irradiation on Earth, or for the fact that half the Earth's surface is by definition not receiving any sunlight at any given time, or for the fact that most of the Earth is water and not land (although I suppose you dropping the 4 from the multiplier for the surface area is meant to account for that). In other words, at no point did I see anything that took into account the error I pointed out.
if you're interested in taking the capacity factor into account, which accounts for things like night, clouds, and oblique illumination, a number of my other notes in https://dercuano.github.io/topics/solar.html (linked from the bottom of my above-linked note) do that; for example in https://dercuano.github.io/notes/japan-energy-autarky.html i calculated that energy autarky for japan, if purely solar, would require 5% of its land area and about 1.7 trillion euros of solar modules, taking into account all of those factors as well as panel efficiency. since then, the price has dropped by more than a factor of 2, but the land area required remains about the same, or slightly increased
(floating that 5% of their land area on solar barges off the coast, instead of occupying precious land area, is also clearly feasible; it just isn't economically competitive, much like nuclear power)
of course, the real-life solution also involves wind and grid-scale storage
perhaps it goes without saying that very few places are as densely populated or as heavily industrialized as japan, so much smaller fractions of their land area would suffice
i'm still waiting, it's been two days
Glad we agree
If anyone's reading this and wants a decent resource I suggest Bill Gates's book How to Avoid a Climate Disaster
"Per MWhr" is a better measure when comparing intermittent-power generation such as wind and solar.
>posting random bullshit
^^
but intermittency is irrelevant to basic incommensurability of units; neither nuclear nor solar uses more and more land over time to produce a constant amount of power, which is what 'land per megawatt hour' implies