How Technology Hijacks People’s Minds

Re:How Technology Hijacks People’s Minds by kragen on Sunday May 22, 2016 @12:40AM (#11747391)

> how do we provide energy ...? Renewables might work - if people stopped having kids for a while

It seems like you haven't done the math. I have. You're ridiculously wrong.

US marketed energy consumption per capita is 9.5 kW (see https://en.wikipedia.org/wiki/List_of_countries_by_energy_co...). That's 9.5 square meters of sunlight. If we pessimistically assume that we can only site solar panels on land (29% of Earth's surface) and only 10% of that, and that we're only using the currently common 16%-efficient polysilicon photovoltaic panels (rather than, say, solar thermal collectors or multijunction cells), then we receive enough solar energy for 60 billion people at current US levels of consumption, according to units(1):

    You have: circlearea(earthradius) * 1000 W/m^2 * 29% * 10% * 16% / 9.5 kW
    You want: billion
	* 62.281752
	/ 0.016056067

That's about eight times Earth's current human population.

Is it too costly? Currently, photovoltaic modules cost about US$0.50 per watt (see http://www.solarserver.com/service/pvx-spot-market-price-ind...), so, for everyone to consume as much marketed energy as USAns, we're talking about an investment of about US$4800 per person, or about US$160 per person per year, assuming a 30-year lifespan for the panels, even if costs didn't drop further. That's only about 1.6% of the nominal world GDP of about US$10k per year per person (see https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nomi...).

And that's just solar photovoltaic. EGS (see https://en.wikipedia.org/wiki/Enhanced_geothermal_system) and oceanic lithium (see https://www.withouthotair.com/c24/page_172.shtml) are two other energy resources of similar magnitude to solar photovoltaic, but they're being developed more slowly — photovoltaic is practical today.

Your comment would have been reasonable ten years ago, when solar PV was still expensive. The facts have changed. When the facts change, I change my opinion. When are you going to change yours?

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Re:How Technology Hijacks People’s Minds by kragen on Tuesday May 24, 2016 @05:15PM (#11765557)

Erratum: that's US$0.50 per peak watt. Although capacity factors vary by latitude and mounting (electronics are now cheap enough that some new utility-scale solar PV boosts its capacity factor with heliostats), a typical capacity factor is 20%, which means:

- US$24000 of panels per person, or

- US$800 per person per year, assuming 30-year lifespan, which is

- 8% of nominal world GDP of US$10k per year per person.

Worse, though, is that this reduces the carrying capacity calculation to some 12 billion, which is a number we might actually reach, although not soon. We're projected to reach 10 billion in 2083 by the UNFPA: https://en.wikipedia.org/wiki/Population_growth

What's actually going to happen, though, is that PV prices will start dropping again; the majority of marketed energy consumption will be from photovoltaic cells starting sometime in the 2020s; energy prices will drop well below where they are now; we'll increase our per capita marketed energy consumption far above current rich-world usage, but much of that will be thermal, not electrical; and we'll use a lot more than 10% of the land area for solar energy gathering.

[ Parent | on HN ]