News for hackers. Stuff that matters.

A comment on CO2 in the atmosphere just exceeded 415ppm for the first time in human history. Parent comment

Re:CO2 in the atmosphere just exceeded 415ppm for the first ... by adrianN on Monday May 13, 2019 @11:53AM (#19900520)
The numbers cited here seemed high to me, so I checked them. Primary energy consumption in the US[1] ~1 * 10 ^ 20 Joules. Divided by population and number of seconds in a year[2] is about 10000 Joules per person-second, so about 10kW per person. A kilowatt of peak solar power requires about 8 square meters of panels[3]. Since the sun doesn't shine all the time and you don't get peak output all the time 750 square meters per person doesn't seem terribly unrealistic.

That being said, there is a lot of space where nobody lives in the US. There are some 28000 square meters per person in the US. Dedicating about 3% of that to solar panels doesn't seem impossible.

Some energy saving is also possible without changing the average lifestyle too much. Insulating homes helps quite a bit. Electric cars are more efficient that gas cars.

[1] https://www.eia.gov/energyexplained/?page=us_energy_home

[2] https://www.wolframalpha.com/input/?i=10%5E20+joules+%2F+(3....

[3] https://www.quora.com/How-much-solar-energy-can-be-tapped-in...

[ Parent | on HN ]
Re:CO2 in the atmosphere just exceeded 415ppm for the first ... by electricityUser on Tuesday May 14, 2019 @05:34AM (#19908026)
You forgot that this is primary energy consumption you two are writing about. 10 kW of primary energy consumption if replaced with solar requires only about a third of that to yield the same results since about two thirds are heat losses when converting fossil fuels to useable energy.
[ Parent | on HN ]
Re:CO2 in the atmosphere just exceeded 415ppm for the first ... by jdietrich on Monday May 13, 2019 @04:10PM (#19903432)
>Since the sun doesn't shine all the time and you don't get peak output all the time 750 square meters per person doesn't seem terribly unrealistic.

At current prices, that much PV capacity would cost around 25 trillion dollars. That price doesn't include any storage capacity.

The climate is changing far too rapidly for us to hope for science fiction solutions. We need a major reduction in emissions now, which means both a vast increase in renewable production and a vast reduction in overall consumption.

[ Parent | on HN ]
Re:CO2 in the atmosphere just exceeded 415ppm for the first ... by electricityUser on Tuesday May 14, 2019 @05:37AM (#19908037)
You only need a third of that to get the same amount of electricity out of them as by burning 10 kW of fossil fuels. Spread over 20 to 30 years that's suddenly not so much anymore. How much does the US spend on energy each year now? How much to secure the imports?
[ Parent | on HN ]