back

by felixbraun·12y ago·view on hn ↗
> SolarCity was founded to accelerate mass adoption of sustainable energy. The sun, that highly convenient and free fusion reactor in the sky, radiates more energy to the Earth in a few hours than the entire human population consumes from all sources in a year. This means that solar panels, paired with batteries to enable power at night, can produce several orders of magnitude more electricity than is consumed by the entirety of human civilization.

Elon shining through here.

There is little doubt that SolarCity will be a huge deal.

2 comments
There’s a non-sequiter in that statement: the authors jump directly from “the sun emits an enormous amount of energy” to “it is feasible to capture and store several orders of magnitude more electricity than is currently consumed by human civilization using only solar panels and batteries.” That is a huge, huge leap.
It's a huge, huge leap of multiplying the wattage of a solar panel by the number of solar panels manufactured and installed.

Looks like it would take less than 1% of the land area of the earth to satisfy the electricity consumption of humanity many times over:

http://www.wolframalpha.com/input/?i=electricity+consumed+%2...

It doesn't seem like much of a leap to propose covering 1% of the world with buildings or roads or farms, so solar panels should seem the same.

I've heard this suggested before, but seriously, 5.1 million square kilometers of solar panels? Seems to me that we're a long way off from that kind of undertaking.
The link is showing 2,000 square kilometers now.

If you plug in a more reasonable value for watts (efficiency, night), it's still tens of thousands of square kilometers, not millions.

Aka less than 1% of 1% of land is enough for solar at today's energy use levels using 20% efficient panels. More reolistically wind and hydro are unlikely to be completly replaced by solar any time soon.

PS: Most homes can meet there total energy needs and have room left on there roof which says something about energy density.

You are confusing “energy use” with “electricity use.” Things like natural gas heating (especially if you live somewhere with really cold winters), gasoline for ground transportation, and jet fuel for air travel, as well as all the different ways these inputs go into, e.g., growing the food we eat and manufacturing household items, form a very large part of the average person in a developed country’s energy use.
Home != People otherwise I would have said People.

Anyway, Solar is actually great for home heating and hot water needs and solar hot water is generally more cost effective to install than rooftop eletric solar. Oddly enough installing solar pool heaters are cheap and fairly common even though they cover a fairly small window over the course of a year.

PS: Rooftop solar ~20% efficient rooftop home heating ~90% efficient.