On the subject of practical plans, or things that might be mistaken for same at first glance, someone on TheTango.net says “Scientists say, if just 1.2% of the Sahara Desert is covered by Solar Panels we could have produce enough energy to power the Entire world.” And you may object that whoever this person is, they’re not a reputable source like say Michael Mann or Al Gore. But it’s a problem when such calculator-free ideas float cheerily about convincing the youth of today that all you need is will. Someday they will be the grumpy adults of tomorrow asking why didn’t someone tell me the Sahara was that big.
Perhaps big isn’t the word. Vast might be more appropriate. According to Wikipedia the Sahara is 9.2 million square kilometers so that disarming “just” conceals that we’re talking about 110,000 square kilometers of solar panels. As Wikipedia also explains, after the surprising news that the only deserts larger than the Sahara are found in the Arctic and in Antarctica.
Another way of expressing it is that the Sahara occupies about 6% of the total land surface area of our planet (148.9 million km2). So the plan is “just” to put solar panels on .07% of our standing room. Which might, one feels compelled to observe, require quite a bit of raw material just to build the panels and their mounts, not to mention the grid to bring all that power from Chad to the Czech Republic, Chile and China. It’s also not obvious where we’d dump all those panels when they wore out in 20 years, unless you’re going on the “when you’ve seen one desert” notion that we can just leave them where they are and panel another 110 thousand square kilometers in 2041 or thereabouts. And a recent Daily Mail piece also observes that the sorts of giant “battery farms” this kind of energy production entails are not without certain dramatic explosive hazards.
If someone proposed filling that much of the Sahara, and the planet, with fossil fuel plants you’d hear a lot of objections including some based on practical calculations. So ideally with solar you’d hear the same… even if “Scientists say”.
Some might be tempted to dismiss this claim as just one odd outlier. But unless proponents of alternative energy start disassociating themselves with such blithely absurd pronouncements, they are guilty of the same kind of fact-free advocacy.
Nobody told these geniuses that the Sahara is filled with shifting sand that will bury the solar panels in days, not weeks. Or that they might find is difficult to get voluntary work crews to do hard physical labour 8 hours per day in 45 degree dry heat, amid sandstorms. This might not be quite the "well-paying green new jobs" the people were thinking about when the politicians promised the sun and the moon for free.
Two more problems with the Sahara scenario:
1. The power generation capacity of 110,000 sq km of solar farms, assuming the actual solar panels occupy about a third of the total area, would be approximately 5000 GW, which would need to be transmitted by high voltage cables hundreds or possibly thousands of kilometres to the end users. Have you any idea of the number and size of transmission lines that would be required for this amount of power? Building all those lines, many of them underwater, would be one of the greatest engineering projects ever undertaken.
2. When one blithely says 'Sahara', you are actually referring to a number of rather politically unstable countries such as Mali, Niger and Libya. Do you really want your entire global energy system to be located at the mercy of whichever local tinpot dictator or terrorist group decides to play around with it?
Every scheme aimed at massively increasing the fraction of electrical generating capacity of wind and solar is, in reality a boon to fossil fuels as the embedded energy in all phases of construction through decommissioning is barely exceeded by their life cycle output, particularly when made only usable to a grid by necessary inefficiencies in the variable output baseload provider. Decades spent satisfying the symbiosis of hysteria merchandizing politics providing rent seeking bounty exclusively to the (CAGW- CO2) hypothesis reinforcers and wind and solar rent seekers instead of focusing valuable Oil, Gas and Coal as a bridge to nuclear power is a guarantee of increased reliance on Oil, Gas and Coal - unless poverty is the real goal.
I guess the mention of millions of batteries covers the “what happens at night?” question ?