HN Distilled

Essential insights from Hacker News discussions

15-Fold increase in solar thermoelectric generator performance

Original Article

Hacker News Discussion

Here's a summary of the themes from the Hacker News discussion:

Thermoelectric Generator (STEG) Technology and Applications

The core of the discussion begins with the introduction of a new Solar Thermoelectric Generator (STEG) that utilizes the Seebeck effect to generate electricity from temperature differences, even in shaded or cloudy conditions. While acknowledging its current low efficiency (~1%) compared to solar panels (~20%), participants recognize its potential in niche applications where traditional solar panels underperform. The technical mechanism is explained as joining two materials (n-type and p-type semiconductors) where a temperature difference causes charge diffusion, generating voltage, analogous to the Peltier effect but in reverse.

  • Explanations of the Seebeck Effect:
    • "Two materials (often n-type and p-type semiconductors) are joined at two junctions, one junction is heated and the other cooled. The temperature difference makes charge diffuse from the hot side toward the cold side, and this charge is what turns into the seebeck voltage they describe." (vasco)
    • "If you've read of the peltier effect, it's the same thing as this, just in reverse." (vasco)
  • Potential Applications Beyond Solar:
    • "I did data collection for a paper looking at the Seebeck effect in magnetic insulators about ~10-15 years ago, and it seemed like everyone in the whole physics department considered spintronics pretty dead. It feels great to see some big promising applications coming out of the field." (blackjack_)
    • "It's not a good solar power source, but could the technology be adapted to heat sinks? Maybe they could license the technology to CoolerMaster." (Animats)
    • "AI data centres can perhaps harvest some of the waste heat back as electricity." (hankman86)
    • "Cars are an obvious application. Some parts get very hot, and any electricity produced without engine or fuel add to range / efficiency." (iTokio)
  • Questions about Efficiency and Comparison:
    • "But do they actually out-perform solar panels in any situation yet?" (IshKebab)
    • "I'm not sure what you mean by solid state AC, peltier cooling? That will never be used for air conditioning, the theoretical max COP is 1 (1w of heat removed for 1w of input power) and a decent heat pump will have a COP of 4 (4w of heat removed for each 1w of input power)." (quickthrowman)
    • "gsf_emergency_2: It's hard to come close to solar cells' Carnot... I don't think they improved "efficiency" by much. That's why by performance they actually mean something like raw power output. TEG is notorious for having like microwatts per sq cm of output near room temp. Now they are a 100th to a 10th of PV "performance".. mildly disingenuous titling imho." (gsf_emergency_2)

China's Science and Technology Strategy vs. US Approach

A significant portion of the discussion touches upon geopolitical aspects of technological development, contrasting China's proactive and diverse approach with what is perceived as a more limited focus in the US. China's strategy is seen as more "outside the box" and encompassing areas like semiconductors and advanced nuclear technologies (e.g., thorium reactors). This is contrasted with a US tendency towards specific, trending R&D areas and a "Drill Baby Drill" mentality, which some believe will lead to negative consequences like atmospheric dimming that could impact solar power.

  • Proactive Chinese Innovation:
    • "It’s explicitly part of Chinese science and technology strategy to think outside the box and it’s what’s pushing them forward on areas like semiconductors as well." (hatenberg)
    • "You’re being downvoted but i don’t think you’re entirely wrong. China has been pursuing some stuff that the western world had essentially abandoned, getting interesting wins (eg: thorium reactors)." (znpy)
  • Critique of US Approach:
    • "Given the massive advantage in talent they’ve built up while the Us reverts to Drill Baby Drill we know how this ends." (hatenberg)
    • "Eventually the Us with push for atmospheric dimming to “fix” the negative externalities of their approach which had the nice side effect of degrading solar …." (hatenberg)
  • Debate on China's Motivation:
    • "He's wrong in the "why" tho. It's not that they must think outside the box, it's that they must not all focus on a single point of research. I'm pretty sure that they are also pursuing popular research topics, because it would be pretty bad if they fall behind for not doing the obvious." (braiamp)
    • "Competition is great." (idiomat9000)

The Future of Energy Generation: Renewables vs. Nuclear

A substantial part of the conversation revolves around the viability and future of different energy generation sources, primarily focusing on the debate between renewables (solar, wind) and nuclear power. Arguments touch upon cost, reliability, intermittency, storage, regulatory hurdles, and environmental impact. There's a strong sentiment that renewables, coupled with battery storage, are becoming increasingly economically favorable and are attracting significantly more investment than nuclear power. However, concerns about the intermittency of renewables and the need for baseload power persist, and some argue that nuclear still offers advantages in specific scenarios.

  • Economic and Investment Trends:
  • Intermittency and Baseload Concerns:
    • "Wind + solar is just adding another failure mode for when there is no wind. There are many places without adequate wind speed. Nuclear does not care about either, and has the highest energy density on top of that." (ekianjo)
    • "You need some kind of baseload generation that’s not dependent on weather, and borrowing this from a neighbour while pretending you don’t need it is like those ‘tiny house’ guys." (taneq)
    • "I’m not sure what you mean by solid state AC, peltier cooling? That will never be used for air conditioning, the theoretical max COP is 1 (1w of heat removed for 1w of input power) and a decent heat pump will have a COP of 4 (4w of heat removed for each 1w of input power)." (quickthrowman)
  • Storage Solutions (Batteries):
    • "But the global energy investment markets paint a very clear picture: solar + wind + battery is the way." (kristopolous)
    • "Battery storage would need another 100x improvement before being usable for such usage. Maybe it will reach that point, maybe not but anyways, you can't plan a grid on non-existing tech. Otherwise I'd pick some better non-existing one" (realusername)
    • "The question becomes is the power production worth the operation and maintenance costs." (aeonik)
    • "You want a 320 GWh installation? You do realize HVDC grids can do 3,000km energy travel, right? That's basically anywhere to anywhere, continental US." (kristopolous)
  • Nuclear Power's Viability and Challenges:
    • "You can't really set aside the reality of the electric grid, you have to do with it." (realusername)
    • "France and China have built nuclear plants in 6 years, and they provide stable power for over 40 years, unlike wind turbines and panels which last maybe 20 for panels (if you're lucky), and a few years for turbine failures, and neither provide stable power." (naasking)
    • "Nuclear costs are largely due to regulatory burdens created for reactor designs that are not safe. That is no longer the case. Also, attempts to exploit economies of scale could also improve baseline costs, although these attempts haven't been funded enough yet to actually scale." (naasking)
    • "Nuclear has its own failure modes. In Switzerland, one of the nuclear plants will be offline for winter (!) due to "unplanned repairs"." (thomasmg)
    • "Nuclear costs would be way higher if the plant operators would need to have insurance for catastrophic failures. Right now, they don't need that. The state (the population) just takes this risk." (thomasmg)
    • "Even ignoring all of that, there's 'time to first watt' - essentially if you break ground now, how quickly can you start producing power? Nuclear has years scale, wind and solar has weeks, if not days." (kristopolous)
    • "Plus you don't have to build Onkalo Repository like systems to store waste for 100,000 years after you've produced your electricity." (kristopolous)
    • "It's wildly more feasible." (kristopolous)
    • "Energy got increasingly expensive in Germany the further the Energiewende agenda advanced, to the point that we’re now rapidly deindustrialising. Turns out base load kinda matters." (MrBuddyCasino)
    • "I'd love to have more modern nuclear, but I don't see it happening anymore, no expertise in building them anymore, cost and time overruns all over..." (cenamus)
    • "In the next years, it doesn't make sense to use batteries to sustain winter load: it would be way too expensive. But batteries get cheaper quickly, such that it doesn't make sense to build expensive nuclear plants just for winter." (thomasmg)

Grid Stability and Management in a Renewable-Dominated Future

The discussion delves into the complexities of grid stability, particularly as the energy mix shifts towards variable renewable sources like wind and solar. Participants discuss concepts like grid inertia, voltage fluctuations, and the role of negative electricity prices in incentivizing storage and demand management. There's also a debate about the risks associated with grid decentralization and the potential for new control mechanisms to maintain synchronization.

  • Grid Inertia and Synchronization:
    • "As the grid moves away from physical inertia sources and loads, do you think it would be realistic to distribute a grid-wide signal separate from the actual line voltage which could assist non-rotating power sources to stay in sync or at least help reduce the chances of oscillation?" (bradfa)
    • "The main reason for negative electricity prices are inflexible generators, eg. nuclear and coal, because they can't easily (cheaply) ramp down or shut off." (thomasmg)
    • "Negative prices are not all bad: they are an incentive for storage / flexible demand to step in. Specially, a negative price does not mean the grid is melting." (thomasmg)
    • "What grid balancing is all about is to make this all financially optimal, it has relatively little to do with the safety of the grid, it is simply a way to extract maximum capacity without affecting that safety." (jacquesm)
  • Experiences with Grid Events and Balancing:
    • "That's genuinely not how it works. You can see it every spring as Germany wholesale prices go negative to try and offload as much electricity as fast as possible to keep their grid from falling over." (masklinn)
    • "iTokio: That’s very interesting, but as a counter point, it seems that the major spain blackout was partially caused by such a voltage increase that was not mitigated properly." (iTokio)
    • "What you could argue if you had read up on this is that there are market operators that do both sides of the market, which sets you up for an Enron like situation because they can make money by front-running." (jacquesm)
  • Advanced Grid Stabilization Technologies:
    • "I think for myself the main takeaway is that we have come to rely on always available grid power to a degree that we probably should not have." (jacquesm)
    • "I think we will see instead is custom superconductance based sink/source units help with local grid stabilization. Those are already being deployed and they work quite well absent mechanical solutions, but they are still expensive and their capacity is still limited." (jacquesm)
    • "Great distribution of generation and consumption in a geographical sense is something we never really gave much consideration in the past... I think we will see more of this as well, and incentives to allow EVs to be used as sinks during times of excess power availability." (jacquesm)

Miscellaneous Technological and Scientific Points

Beyond the main themes, several other interesting technical and scientific observations were made:

  • Spintronics and Potential: The mention of spintronics research from a decade ago, which was then considered "dead," and its resurgence with promising applications, highlights the cyclical and often unpredictable nature of scientific progress.
  • Laser Patterning Advancements: The discussion touches on laser patterning of metals as a significant advancement, potentially more accessible than improving thermoelectric material efficiency.
  • "Fold" Terminology: A mini-debate ensued regarding the precise meaning of the term "fold" in scientific contexts, specifically whether it implies multiplication by 15 or a doubling that is repeated.
  • Peltier Cooling Efficiency: The extreme inefficiency of Peltier coolers for air conditioning compared to heat pumps was highlighted, making them impractical for such large-scale applications.