Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Solar and batteries can power the world

nworbmot.org

Post reply on HN
Print view View original

361–370 of 473 posts

Re: Solar and batteries can power the world

#361

Post by eigenspace »

mikewarot wrote: post #316

It's important to note that electricity is 21% of the World's energy demand, according to the IEA[1]. This implies that if we could 10x solar, and figure out how to convert some of that to liquid fuels with decent efficiency, we could become sustainable for all energy. [1] https://www.iea.org/world/energy-mix

That's a very silly way to compare energy usage.

For example, you're counting all the energy in the gasoline that gets loaded into a car, not the useful work that the gasoline actually produces. Gasoline gars typically are only able to convert 20-30% of their fuel into propulsion.

Counting the energy in the fuel loaded into engines is like counting the amount of energy in the sunlight hitting a solar panel.

Similar things go for heating by the way. A modern heat pump often has a coefficient of performance of around 3x, meaning that for every joule of electricity you put into the pump, you can heat up a house with 3 joules of heat, so 3x as efficient as heating the house with combustion.

Re: Solar and batteries can power the world

#362

Post by asdff »

chongli wrote: post #302
sillyfluke wrote: post #137

Earlier quoted context omitted.

>66F is ridiculously cold to me...I would find that very uncomfortable and elderly people would be shivering constantly and highly susceptible to respiratory illness. I know people who live in the Mediterranean and get by with no heating during the winter with indoor and outdoor tempuratures this low or lower, so it seems that one can be conditioned into doing so. Perhaps it's the presence of more sunlight on average…

You’re forgetting about humidity. Mediterranean climate has comfortable humidity year-round. Where I live, winter relative humidity is 0% because outdoor humidity is nonexistent from freezing temperatures.

Med climate isn't always great year round. They can get winds blowing down from the north that freeze the coast:

https://en.wikipedia.org/wiki/Bora_(wind)

Re: Solar and batteries can power the world

#363

Post by coryrc »

jakewins wrote: post #319
coryrc wrote: post #203

Earlier quoted context omitted.

I bet you didn't even see the tragic farce when writing your solution. Land development requiring ”2-car homes" is the driver of the problem! An apartment only has to heat one or two walls facing the outside instead of 4. That's 50-75% right off the top of your energy usage, with the mean closer to 75%.

No reason to be rude or hyperbolic - I agree with you that cars destroy communities and we should strive to reduce the need for cars and parking. For solar powered homes specifically though, multi-story buildings are much harder to run solar powered from the simple ratios - even if you reduce energy use 75%, at 4 stories you are break-even in roof-ratio-to-energy-need. I’ve worked in this space a while, and it’s now…

I mostly agree with you, however...

You don't need to colocate solar at the point it's used. Utility solar is cheaper than rooftop, by multiple.

The last part isn't true. There's no way you're running a home, including heat, entirely of solar in the winter in the Upper Peninsula of Michigan.

Re: Solar and batteries can power the world

#364

Post by morphle »

declan_roberts wrote: post #5

The article is just wrong. And only mentions energy used for heating in passing. Heating requires MASSIVE amounts of energy. I should know bc I have a whole house battery and solar system (almost 30 kWh battery and 24kW solar). It keeps the lights on, but not heating. I live in a mild climate. The reality is that battery/solar requires major quality of life and activity time shifting trade-offs.

You should store your solar energy as heat. You move the heat from outside or underground into your house with a heat pump where the heat storage lasts a week or more. You need very little solar to heat your house this way.

So for a mild climate your installer seems to have done you a disservice and probably overcharged you. You can heat an average house with solar for under $14K if properly installed.

Re: Solar and batteries can power the world

#365

Post by tzs »

bb88 wrote: post #184
germandiago wrote: post #92

Earlier quoted context omitted.

So here I go: if it is so stupid, why it is not done yet? Try not to blame anyone. Do it rationally if you can, from your message I understand your opinion. I say this as a person that has lived in a developing country the last 15 years. It is not that simple IMHO...

1. Solar panels need a huge capital expenditure up front. 2. Wind power works better for farmers and provide a smaller footprint. Drive on I-80 in Iowa on a clear night and you'll see the wind farms blink their red lights in the distance. Farmers can lease their land for wind turbines, and the generation companies take on the regulatory / capital / politcal risks, etc. 3. Farming is more or less free market based, an…

> As a side note, agriculture uses up lots of water in deserts (more so than people), so it seems like in desert spaces like Idaho, solar would make a lot more sense than agriculture would. And we should move the agriculture to where the water naturally falls from the skies.

The problem is that in many of those places where enough water naturally falls from the sky the soil and/or the weather isn't as good for growing food.

It is generally much easier to move water to a low water place that has great soil and/or weather than it is to move soil or weather to a high water place that is missing good soil or weather, and so here we are.

Re: Solar and batteries can power the world

#366

Post by balderdash »

enslavedrobot wrote: post #338
opo wrote: post #199

Earlier quoted context omitted.

The consumer rooftop solar cost is usually one of the most expensive ways you can generate electricity - often several times the cost of utility solar installations. The high rooftop solar price is usually hidden (at least in the USA) because no power source has been as subsidized as rooftop solar. Besides direct subsidies, wealthier home owners have often been paid the retail rate for the electricity they sell to th…

Rooftop solar in Australia is ~60cents per Watt installed.

in the US - admittedly 4 years old info, the cost of utility scale solar was like ~$1/watt - rooftop solar was like $2.5-$3/watt

Re: Solar and batteries can power the world

#367

Post by laurencerowe »

asdff wrote: post #351
laurencerowe wrote: post #349

Earlier quoted context omitted.

Opportunity costs essentially. The effort that goes into growing and refining corn ethanol could be better spent on reducing fuel consumption instead of dedicating five acres of land to provide the equivalent net yearly fossil fuel consumption of a single average car using 500 gallons of gasoline to drive about 15000 miles.

Why not do both, reduce fuel consumption while shifting to a carbon neutral fuel source that is fully onshored?

Again opportunity costs. It almost always makes sense to spend the money on the most efficient means to achieve the goal. Money spent paying farmers and ethanol refiners to inefficiently produce 25% lower carbon fuel could instead be directed at other endeavours that for the same cost reduce carbon emissions more.

Re: Solar and batteries can power the world

#369

Post by [deleted] »

anon7000 wrote: post #61
mbesto wrote: post #41

Fun fact, 12 million hectares of land of used to produce corn used for ethanol which is used to produce gas. I'll let you draw the conclusion. https://news.cornell.edu/stories/2025/04/trading-some-corn-e...

Yeah, the technology connections video on this was fantastic. If one was to cover that land in solar, you’d produce far more than the current energy demands of the US. Relying on an energy source which requires constant, continuous resource extraction is fucking stupid when we can spend resources up front and get reliable energy (solar + battery) for decades with minimal operating cost & maintenance. And then we’ll h…

[deleted]

Re: Solar and batteries can power the world

#370

Post by [deleted] »

jacquesm wrote: post #146
FEELmyAGI wrote: post #140

Earlier quoted context omitted.

What does the 1% of land used to grow corn have to do specifically with solar and batteries? Solar doesn't need to be on the 15% arable land at all. The corn doesn't just produce ethanol, which just utilizes the starch/sugar. The protein, fat, fiber is eaten by livestock in some form like distillers grains. And governments like to have food security , and having secondary uses for an abundance of food in the good tim…

My conclusion is that you didn't even try to understand the GP.

[deleted]
Post reply on HN