Earlier quoted context omitted.
We already have a fusion reactor at a relatively safe distance called the sun.
We also have this thing called night, as well as weather and seasons.
US startup begins producing 40%-efficient thermophotovoltaic cells
51–60 of 174 posts
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#52Earlier quoted context omitted.
I believe we will build a functional net energy gain fusion reactor probably in the next decade if things go well (I’m rooting for SPARC), but we will still need to build an actual power plant (designed for long life, serviceability, improve efficiency based on what was learned before) and that will take a while. And then we need to build lots of them. And they will be very expensive. Probably fusion power will not b…
Even if fusion was widely available and affordable you will still want other sources of power for peak demand. Like fission nuclear reactors, they will be good for base power-load. Fusion reactors won't be able to spin up and down based on demand willy nilly. Given most demand is during the day and early evening solar is a good complement, but the more mixed renewals you have in your grid the better it will tolerate…
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#53I don't get why they go for storage with this. Storing a block of carbon or tungsten at 2000°C for hours or days does not sound like something that will ever be economical. A battery leaking energy this quickly (and it will leak₎ will need to be incredibly cheap to ever make sense. I wonder if you could use this with parabolic mirrors, though. Build a large mirror array, focus sunlight onto a big carbon sphere (maybe…
With grid scale, above certain dimensions, you can store energy for months while maintaining economic viability.
Even for single days or weeks it makes sense. You need hot water in your home 24/7, but sun doesn't shine every day in most regions.
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#54I don't get why they go for storage with this. Storing a block of carbon or tungsten at 2000°C for hours or days does not sound like something that will ever be economical. A battery leaking energy this quickly (and it will leak₎ will need to be incredibly cheap to ever make sense. I wonder if you could use this with parabolic mirrors, though. Build a large mirror array, focus sunlight onto a big carbon sphere (maybe…
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#55Earlier quoted context omitted.
There are betavoltaic generators [1] that directly produce electricity from decay electrons using p-n junctions (similar to photovoltaic cells). However, in the vast majority of applications, they get outperformed by modern lithium batteries (i.e. coin cells). [1] https://en.m.wikipedia.org/wiki/Betavoltaic_device
How can you compare a generator to a battery? How do you charge the battery without a generator?
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#56Stupid question: could this be used underground in volcanic areas like Iceland?
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#57I don't get why they go for storage with this. Storing a block of carbon or tungsten at 2000°C for hours or days does not sound like something that will ever be economical. A battery leaking energy this quickly (and it will leak₎ will need to be incredibly cheap to ever make sense. I wonder if you could use this with parabolic mirrors, though. Build a large mirror array, focus sunlight onto a big carbon sphere (maybe…
If you try that with solar radiation, you'll lose most of it back into the sky.
https://www.nature.com/articles/s41586-022-04473-y.pdf
(Equation 1 and surrounding discussion, and the energy-flow diagrams in Figure 1).
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#58Earlier quoted context omitted.
Moonlight is ~1 mW/m^2, so good luck with that.
I was thinking you could cover the moon in rotating mirrors to redirect the light to solar panels. And if they can be controlled independently, you can tweak them and basically use the surface of the moon as a giant display, who wouldn't want the moon to look like a giant Apple logo?
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#59Stupid question: could this be used underground in volcanic areas like Iceland?
My understanding is that to get those kinds of temperatures from geothermal you need to drill to currently infeasible depths.
But you don’t need those kinds of temperatures from a geothermal resource to make it very cost-competitive.
Re: US startup begins producing 40%-efficient thermophotovoltaic cells
#60I don't get why they go for storage with this. Storing a block of carbon or tungsten at 2000°C for hours or days does not sound like something that will ever be economical. A battery leaking energy this quickly (and it will leak₎ will need to be incredibly cheap to ever make sense. I wonder if you could use this with parabolic mirrors, though. Build a large mirror array, focus sunlight onto a big carbon sphere (maybe…