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US startup begins producing 40%-efficient thermophotovoltaic cells

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Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#161

Post by adwn »

bluGill wrote: post #135
adwn wrote: post #95

Earlier quoted context omitted.

> Why do we insist on our energy system to be infinitely flexible and full power available 24/7? I like to heat my home during winter. We have a (modern, highly efficient) heat pump, so we need most electricity during January, just when the least amount of solar insolation is available [1] and when it sometimes stays cloudy and below 0°C continuously for days. But I guess we'll just have to be more flexible and turn…

You don't actually need your heat pump 24x7 even on those cold days, if you can run for 15 minutes one, 15 off that would make a big difference to the grid (your neighbor running the same schedule but opposite times) without making your house too cold. Managing the above is tricky though.

> You don't actually need your heat pump 24x7 even on those cold days, if you can run for 15 minutes one, 15 off that would make a big difference to the grid

That's already the case – the actual heat pump only runs intermittently, on demand. This happens quasi-randomly, so you automatically get some load balancing across a city.

The problem is that this is intra-day load balancing, which doesn't help one bit if there are several days of low supply (windless winter days).

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#162

Post by adwn »

lazide wrote: post #122
adwn wrote: post #95

Earlier quoted context omitted.

> Why do we insist on our energy system to be infinitely flexible and full power available 24/7? I like to heat my home during winter. We have a (modern, highly efficient) heat pump, so we need most electricity during January, just when the least amount of solar insolation is available [1] and when it sometimes stays cloudy and below 0°C continuously for days. But I guess we'll just have to be more flexible and turn…

Regarding [1] - are you being sarcastic?

Is that a serious question?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#163

Post by bluGill »

adwn wrote: post #161
bluGill wrote: post #135

Earlier quoted context omitted.

You don't actually need your heat pump 24x7 even on those cold days, if you can run for 15 minutes one, 15 off that would make a big difference to the grid (your neighbor running the same schedule but opposite times) without making your house too cold. Managing the above is tricky though.

> You don't actually need your heat pump 24x7 even on those cold days, if you can run for 15 minutes one, 15 off that would make a big difference to the grid That's already the case – the actual heat pump only runs intermittently, on demand. This happens quasi-randomly, so you automatically get some load balancing across a city. The problem is that this is intra-day load balancing, which doesn't help one bit if there…

What your thermostat does is not synchronized with your neighbors, so the peak load is not managed.

It also isn't synced to supply, instead most people have it set to different temperatures based on when they are home. It would be better to cool or heat the house based on supply. You want the house between 21 and 24c, you don't care when the system is on.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#164

Post by lazide »

adwn wrote: post #162
lazide wrote: post #122

Earlier quoted context omitted.

Regarding [1] - are you being sarcastic?

Is that a serious question?

Yes. The dominant (essentially only at the surface) source of heat on the planet is the Sun? When would insolation NOT correlate with temperature?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#165

Post by BenjiWiebe »

amluto wrote: post #154
pbmonster wrote: post #147

Earlier quoted context omitted.

Ok, so you recirculate exhaust into the combustion chamber and inject new fuel. Now what? It doesn't burn, since there is no oxidizer. The only way is to inject some. And since you don't want nitrogen, you can't inject air. So you inject pure oxygen, or something like peroxide? Sounds expensive.

There are multiple ways to separate air into a fraction with more oxygen and a fraction with less oxygen, on site, at reasonable scale. Pressure Swing Adsorption is a common one, found in most medical oxygen concentrators.

That would need to be a fraction with no nitrogen, right? Isn't the nitrogen the problem?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#166

Post by adwn »

lazide wrote: post #164
adwn wrote: post #162

Earlier quoted context omitted.

Is that a serious question?

Yes. The dominant (essentially only at the surface) source of heat on the planet is the Sun? When would insolation NOT correlate with temperature?

Of course it was sarcasm. I meant to highlight the major problem for using renewables for heating: you'll need most of the power when the least amount of daily solar insolation is available – in winter. This means you either need a lot of storage capacity, or a lot of transfer capacity from far away places, to cover several days of dunkelflaute [1]. This problem is solvable, but it's hard and expensive to solve in practice.

[1] https://en.wikipedia.org/wiki/Dunkelflaute

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#167

Post by lazide »

adwn wrote: post #166
lazide wrote: post #164

Earlier quoted context omitted.

Yes. The dominant (essentially only at the surface) source of heat on the planet is the Sun? When would insolation NOT correlate with temperature?

Of course it was sarcasm. I meant to highlight the major problem for using renewables for heating: you'll need most of the power when the least amount of daily solar insolation is available – in winter. This means you either need a lot of storage capacity, or a lot of transfer capacity from far away places, to cover several days of dunkelflaute [1]. This problem is solvable, but it's hard and expensive to solve in pr…

I couldn’t tell because many people make arguments (or imply) that it doesn’t matter with an apparently straight face all the time! Including large scale gov’t programs.

Including other comments on this exact thread where people did exactly that.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#168

Post by ChrisRR »

bluGill wrote: post #133
ChrisRR wrote: post #77

Earlier quoted context omitted.

I don't know why people always comment this on posts about renewables as if it's some kind of gotcha. When there's no sun, then other countries probably have sun. When there's no sun, there's hydro. When there's no hydro there's wind. When there's no wind, there's tidal. When there's no tidal there's geothermal. And when there's none of those, there's stored energy in batteries. And if for some reason all of those co…

While other countries have sun when it is night here, realistically we cannot build the needed wires to get that energy here. We need 20,000km of wire to get power around the earth at the equator. Wind suffers the same problem as the sun in that sometimes there is no wind anyplace close, and it is even less predictable. While tide power is predictable and consistent, I don't live anywhere close to the ocean so we sti…

But you've just done exactly what I said people do wrong. Why do people only consider absolutes when talking renewables. We're not relying on a single source, and we're not relying on countries exactly the other side of the world.

Sure you don't have to have a single wire from one side of the planet to the other, but that's the point in a power grid. Even connecting two solar farms to the grid a time zone apart provides an extra hour of power to each of those time zones and reduces the risk of a single cloud bringing the country down

And as for the rest, you know what the electricity grid is right? Cables already run around the country, and if anything this reduces the strain on single connection as there are lots of smaller generators dotted around the country rather than a huge point of failure connected to a single power plant

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#169

Post by ChrisRR »

lazide wrote: post #120
ChrisRR wrote: post #77

Earlier quoted context omitted.

I don't know why people always comment this on posts about renewables as if it's some kind of gotcha. When there's no sun, then other countries probably have sun. When there's no sun, there's hydro. When there's no hydro there's wind. When there's no wind, there's tidal. When there's no tidal there's geothermal. And when there's none of those, there's stored energy in batteries. And if for some reason all of those co…

Many of the plans for the future currently involve drastically undersized battery storage and decommissioning nuclear. That’s why.

So... my point still stands even without nuclear?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#170

Post by lazide »

ChrisRR wrote: post #169
lazide wrote: post #120

Earlier quoted context omitted.

Many of the plans for the future currently involve drastically undersized battery storage and decommissioning nuclear. That’s why.

So... my point still stands even without nuclear?

I can’t tell what your point is, frankly. That everything is fine until it isn’t, then we’re boned? Or that it will never go wrong, unless we have ‘bigger problems’? (Which are what exactly? alien invasion?)

Lack of power either way certainly won’t help!

If by design nuclear is offline, fossil fuels are offline, and battery capacity (or other storage) is insufficient for known (but infrequent) weather events, then we’re designing an inevitable and destructive catastrophe as we have no Plan B for when realtime production is insufficient.

And that will happen some day, regardless of how much capacity we build. It’s currently the norm on many days.

One that will kill a lot of people, especially the physically weaker ones, and be very destructive economically.

One that will also play out randomly based on weather, and for which we’ll have no real Plan B.

Being flippant about it seems rather macabre.

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