How many solar panels would be required to 'pave over death valley'?
For large-scale installations, we have better, simpler, old-school tech than installing actual solar panels. My point more addressed the will, not the specifics.
TFA claims that we can't meet the world's power needs with renewables. I call BS, we just don't have the will to move off of the sweet, sweet teat of oil, for which we already have massive infrastructure in place to support its use. Do you have any idea how many gas stations the US has? How many miles of oil and natural gas pipelines exist? How much effort and expense goes into maintaining those?
To directly answer your question, though, it would take almost exactly six billion panels to literally pave Death Valley. We wouldn't actually need that many, however, since the entire annual US electric budget only comes in at 4,138TWh - Which a mere 5.2B (cheap consumer-grade) panels would satisfy. But as I mentioned above, we wouldn't really use 5.2 cheap consumer-grade billion panels - We'd use either an array of more traditional solar thermal plants (aka lots of cheap mirrors heat something up), or at the very least, use newer, more efficient and multi-sun panels with their own array of mirrors. Current cells exist that can take 70k suns - Lowering the number of actual panels needed (as opposed to cheap mirrors) to a manageable 74 thousand.