Hacker News Reader

Comment by akuji1993 | Hacker News Reader

akuji1993

Stupid question incoming. Does it really help us to trap even more CO2 under the surface? If something exposes that CO2 again, it will be back up in the atmosphere right? So it feels like this would be a "solution" like storing used uranium underground in lead containers - eventually it will become a problem. Or am I completely wrong here?

View on HN

The carbon being released now used to be stored underground in oil and coal, or in trees and soil. We're not creating any more carbon. We're just releasing what was stored, and the solution is to put it back in storage.

"We're not creating any more carbon" Exactly.

"The law implies that mass can neither be created nor destroyed, although it may be rearranged in space, or the entities associated with it may be changed in form"

https://en.wikipedia.org/wiki/Conservation_of_mass

Your question isn't stupid.

Right now though, we are storing our CO2 in the atmosphere. This causes problems. To solve those problems, we need to store the CO2 somewhere else.

It can be released again, but lets hope that the massive effort required to yank the CO2 out of our atmosphere causes the sunk cost fallacy to kick in until we've completely moved past fossile fuels.

I do not expect that we will be able to move past fossil fuels in the next 100 years.

There is simply no other source of energy with as much density and as convenient as oil. The only think we know that can rival oil is nuclear energy but it has problems of its own.

Honestly, there's a lot of stuff I'm skeptical about what will happen in the next 100 years. I don't think that fossil fuels will be a thing in 100 years though. I think we'll have something smarter figured out. Think about how much time has passed since 1918 and what we achieved in that time frame.

Exactly, we haven't achieved that much actually. Most of the technology we use for harvesting energy is not much further from what people could imagine in 19th century. Turbine was invented in the 19th century.

I really suggest watching this talk by Smil https://www.youtube.com/watch?v=5guXaWwQpe4 and if you are interested reading some books from him about energy and oil. Really insightful.

All chemical energy available through coal and oil stored in the earth is the product of a massive amount of highly ineffecient capture of energy from sunlight. [0]

All wind is caused directly by unequal warming of our planet through sunlight. The average hurricane individually releases more energy than entire world population has exhausted, since the dawn of time. [1]

Sunlight is plenty enough. The problem is cheap, clean storage.

[0] - https://en.wikipedia.org/wiki/Photosynthesis

[1] - https://science.howstuffworks.com/environmental/energy/energ...

Another problem is energy density as I said. How much solar energy can you harvest from one square kilometer? I am so surprised that people just handwave this basic fundamental limits away and don't realize that we would have to build solar panels on an enormous percentage of planet for it to be able to replace fossil fuels.

Also managing the lifecycle and production of these panels is another issue. And don't forget that you still need to grow crops somewhere.

Currently only less than 2 % of the energy we use comes from solar energy and 87 % comes from fossil fuels. The cost of replacing the infrastructure is enormous and there is not much incentive to do it as long as we have plenty of cheap oil (which is going to stay with us for at least another century according to estimates).

Why is it so unimaginable that we will still be using oil in 100 years? It might not be 87 % as it is today, it might be 30 % but I am very sceptical that we will be able to completely replace the infrastructure we have build in the last 200 years.

> Another problem is energy density as I said. How much solar energy can you harvest from one square kilometer? I am so surprised that people just handwave this basic fundamental limits away and don't realize that we would have to build solar panels on an enormous percentage of planet for it to be able to replace fossil fuels.

What are you talking about? From Elon Musk's TED talk, this is the area of solar panels required to power all of the US.

http://sustainsubstance.org/images/storage/2015-musk-bluesqu...

A single solar farm of 1km sq can provide enough power for several ten thousand homes, and we have several million square miles of unusuable land lying around in the countries that receive the most sunlight, so land isn't the issue.

That doesn't include solar panels that could actually be installed on the homes. A single roof entirely covered by solar panels can power a LEED-certified home when used in conjunction with battery storage. (Most solar panel setups do not cover the entire rough but still provide sufficient power for all but the most intensive uses, like refrigerators and A/C.)

Farmland, by and large, isn't the best land for solar panels anyway, so the two would generally not come into conflict.

The Mojave Desert. It’s 48,000 square miles and almost uninhabited. We need 2% of that for almost 1000 sq miles. The Trump admin has approved that land for solar but the environmentalists are fighting hard against it, making bidding companies wary that it won’t be worth it. The location is perfect to supply Vegas, Phoenix, LA, and Texas easy. And can also do NorCal and more. It’ll get you 167GW capacity of solar. More than our current wind and solar combined and almost 10% of electricity generation of the country. Rooftop solar on the 30 biggest businesses in America would also yield a ton of solar, read a study the other day on that.

But...you do have a point even though the first part was wrong. Honestly, anything above 50% solar and wind is useless. Need to make up that cost via hydro, nuclear, or storage.

There is no pretense that a non-fossil fuel vehicle must have an energy density >= oil for it to be a viable alternative. A bicycle doesn't carry any energy at all and yet many people use them in place of a car.

I am still waiting for flying bicycles.

Also, why do you mention only vehicles? 87 % of ALL the energy we use comes from fossil fuels (coal + gas + oil).

I don't believe there is enough fossil fuel that can be economically used for that long at rates close to the current.

Storing used uranium is actually pretty effective in the long term. The other byproducts wear themselves out, and the uranium itself is semi-safe.

I don’t think it can truly use seaweed to sequester carbon unless we harvest the seaweed and entomb it underground - but it has to be somewhere the decomposition won’t leak carbon into the atmosphere.

The (early) findings of the study is that is sequestered from leaking into the atmosphere. From the article: "The study estimated that about 11 percent of total seaweed production may be sequestered, most of it after it sinks down into the deep sea."

I don't think carbon is that volatile.

Reply on news.ycombinator.com