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Comment by iljah | Hacker News Reader

This energy storage system near Helsinki, Finland operated by Helen (https://en.wikipedia.org/wiki/Helen_Oy) might be interesting for HN readers. Some facts from previous article (https://www.helen.fi/en/news/2020/mustikkamaa), not sure which one would've been better in url field: District heat is stored in two rock caverns in Mustikkamaa. The temperature of the water in the caverns varies between 50 and 90 °C. The effective volume of the cavern storage facility is 260000 cubic metres and energy capacity about 11500 MWh. The charging and discharging capacity is 120 MW. The discharging or charging of the heat caverns at full power takes four days. The rock caverns will decrease Helen’s carbon dioxide emissions by 21000 tonnes per year. The stored heat can be used for balancing demand peaks and that way cutting fossil heat production, for example, in cold winter days.

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This is a cool project, and I'm sure it has many benefits beyond just carbon savings. But 21,000 tonnes per year is surprisingly little in the scheme of things. Equivalent of about 150 or so long-haul 777 flights?

Just for one city.

If I’m reading this report correctly:

https://julkaisut.hel.fi/en/reports/environmental-report-202...

It looks like the emissions for the Helsinki area are 2,345 kt per year, so I guess 21 kt is only a small part of that.

Of course, no one project should be expected to solve everything! But it is depressing to see the scale of the problem.

1% reduction from one project seems pretty decent to me. Especially when it's just from reusing pre-existing caverns from oil storage to decrease the district heat emissions.

Heating emissions for a city at 60° North are a big challenge to reduce, and combined heat and power is a huge efficiency gain - the heat is otherwise wasted, and thermal emissions are an environmental issue in their own right.

The emissions could be reduced much further if they decrease the 55% of their generation that comes from fossil fuel fired CHP plants[1], and increased their nuclear capacity from current 27% (unfortunately they had to cancel a plan to build another reactor because their partner was rosatom[2])

[1] https://fi.wikipedia.org/wiki/Helen

[2] https://en.wikipedia.org/wiki/Nuclear_power_in_Finland#React...

Heating is perhaps unsurprisingly a large part of overall energy consumption in the Northern hemisphere.

Helsinki shut down one coal plant used for district heating this spring and is shutting down the last remaining one next spring, well ahead of schedule.

https://www.hel.fi/en/news/helen-phases-out-coal-more-than-f...

I personally am bullish on deep geothermal - there was a pilot project near Helsinki which was unfortunately unsuccessful, but with cheaper new drilling tech (plasma etc) I think this can work out in the future. https://www.st1.com/st1s-otaniemi-geothermal-pilot-projects-...

There are also some startups looking to build small modular nuclear reactors for district heating - https://www.steadyenergy.com/

Yep, deep geothermal would be cool, but not as mature. Was specifically advocating nuclear as it is basically a drop in replacement for fossil fuel in existing CHP plants. SMRs might work, though I am somewhat skeptical of anyone proposing "this brand new nuclear tech!" as a solution to difficulties constructing proven nuclear tech - we have decades of examples showing they basically swap one issue for another

agree, I think it could take 7-10+ years for either (deep geothermal or SMRs) to be viable at scale. But once they are, it should hopefully solve carbon neutral heating for good - in areas with district heating at least.

Steady Energy is a spin-off from VTT (Finnish state technical research centre) - I haven't followed it too closely but they are legit. https://www.ldr-reactor.fi/en/development/

Can't be much worse than building another large scale nuclear plant with the French :D (which is what we did with the last one - https://en.wikipedia.org/wiki/Olkiluoto_Nuclear_Power_Plant#... - 4x over budget and 14 years behind schedule)

Yep, the EPR design has had major constructability issues with every site (except the one in China, but there may be a lack of transparency with any issues/solutions that were done with them). EPR2 looks specifically to address the issues they've faced at Hinkley, Olkiluoto, and Flamanville ... we'll see how it turns out, hopefully it isn't just another example of throwing out one set of issues for a different set.

Most large construction projects suffer when there is too great a separation between design and construction. There needs to be feedback from one to the other, and when it takes 30 years to go from conceptual design to operational reactor, that feedback loop just isn't there. One big promise of SMRs is for components to be prefabricated - if you're building multiple of an object, the connection between design and construction will be much closer.

Nuclear is often touted as a carbon solution (especially here on HN!) but the enormous cost and long construction times make it somewhat ineffective at reducing emissions compared to other technologies.

Given that governments and utilities operate with finite budgets, for each € invested in nuclear, we’re actually much better off investing in lower-cost, lower-risk projects and technologies (renewables, electrification, heat pumps, grid upgrades, insulation, storage, etc) that deliver more carbon savings per € spent much more quickly.

To put this in perspective: you could build on the order of 1000 Mustikkamaa heat caverns for the price of one nuclear plant!

> for each € invested in nuclear, we’re actually much better off investing in lower-cost, lower-risk projects and technologies (renewables, electrification, heat pumps, grid upgrades, insulation, storage, etc) that deliver more carbon savings per € spent much more quickly.

Don't get me wrong, I absolutely think all those are key, and need to be focused on immediately. Those help to reduce demand, but (with the exception of renewables) don't help improve supply. If we want to eliminate carbon emissions worldwide, nuclear will be a key component (along with massive renewables). For example, the Japanese grid has been developing various renewables on superdrive since 2011, yet they are only at 20% renewable, with national carbon emissions ~500gCO2/kWh - dramatically higher than when their nuclear fleet was operational. Germany has been pushing renewables for close to two decades, but they closed down their nuclear plants and are similarly at ~500gCO2/kWh. France has had a nuclear-based grid for a couple decades and while it has its own issues, their emissions intensity is ~50gCO2/kWh. Ontario is hydro and nuke, they're ~100gCO2/kWh (some storage and more renewables would help them dramatically reduce emissions from gas, but current conservative premier spent billions scrapping that plan)

> To put this in perspective: you could build on the order of 1000 Mustikkamaa heat caverns for the price of one nuclear plant!

Yes, all you need is 1000 old oil storage caverns already dug sitting there waiting to be filled with water...

The problem with this analysis is that existing renewable capacity was largely constructed during a time when renewables cost dramatically more than fossil energy and nuclear. We’re now moving into a period where they cost dramatically less, and the capacity to build them is vastly greater. We’ve already passed the tipping point for most types of generation, and the cost decreases don’t seem poised to stop. So it’s sort of like watching the first generation of inexpensive Intel PC CPUs roll out of the fab, while simultaneously pointing out that PCs were too expensive to get much adoption in the past. Technically a valid thing to observe, but also not really useful.

To give you some sense of the enormity of the change, China over the first 9 months of 2023 built 215 TWh of wind and PV (numbers already adjusted for capacity factor), which eclipses the combined 206 TWh of every single nuclear power plant they have under construction today (there are 26 of them.)

That tells you how pointless all the at-home energy savings are when everyone and their dog flies to a weekend getaway every month

I know people who attend sit-in protests at Chase Bank locations over fossil fuel divestment who also fly internationally 3-4 times per year for pleasure. The cognitive dissonance and lack of engineering intuition among the general populace is staggering.

I thought pleasure is more important than business. The only reason I do business at all is to feed my interest in doing whatever I like.

If there were less investment in fossil fuel exploration, prices for fossil fuels could rise and airfare might be priced more appropriately. They would fly less because it cost more, or trains and boats might become more competitive.

Moaning about individual "cognitive dissonance" is absolute nonsense when talking about global scale problems that require policy solutions. The activists' intuitions are more correct than yours, I'd wager. Climate change is not an engineering problem.

Protesting Chase doesn’t stop investments. It just pushes them elsewhere. Those activists are morons and stopping their flights would do far more to help than to protest a single bank.

If they were protesting the government to massively increase oil taxes then you might have a point. Alas, they don’t have any economic intuition.

If those protestors did not have tickets on those flights, somebody else would be able to purchase them. It's not like the plane isn't going to fly that route because of this. So whether the protesters fly or somebody else, the plane is still make the emissions you're concerned about.

If enough people didn't buy tickets, then the airlines would have to reduce capacity on the routes, and that would reduce emissions.

what's more likely, people stop traveling by plane, or these seats will remain filled? I'm all for making changes, but let's make them realistic ones with actual chances of getting implemented. the world is a big place, and air travel is not going to be replaced by steamships. we've been there, done that, and tired of the slowness. progress, not regression. improve the engines for air travel. don't expect air travel to stop

“If I don’t rob this bank, someone else will!”

They're not protesting Chase, they're protesting fuel investments. If government did its job, this wouldn't even be needed.

https://www.theatlantic.com/science/archive/2023/11/climate-...

> The international agency’s analysis, in contrast, assumes countries will follow through with more climate-friendly policies and renew the ones they already have on the books. “Look how different things could be,” Bowman said. The difference is night and day, despair and hope.

> Policy, and only policy, appears to make that difference. It represents the choices that our leaders make about when to finally change course. Naughten, the Antarctic-ice scientist, reminded me that “climate is a spectrum; it isn’t an on/off switch.” Whenever we do make a different set of decisions, ones that make the math properly compute, we will be saving what we have left, preventing some layer of livability from being irrecoverably sloughed off and swept away.

What do you think trains and ships are fueled with exactly?

This level of comment is honestly insulting on this site.

In case anyone needs it spelled out: train and boat travel are vastly more energy efficient than air travel.

If fossil fuels rise, the cost of transportation of EVERYTHING goes up and the entire economy explode. Do you want 50% annual inflation? What you saw during COVID would only be a taste.

Your comments are an insult to readers' intelligence. Efficiency is good. Cutting fossil fuel use ASAP is crucial for the future of humanity. Shifting demand from air travel to high speed rail and from air cargo to ocean freight are unalloyed goods.

If you want to bleat nonsense about imagined 50% inflation, please go do it on twitter.

I suggest you read the HN guidelines about personal attacks.

Or they want to look like they care, while having as much fun as possible?

there are other ways to look at it though

Is it more or less hypocritical than someone who pays lip service to climate change, flies 3-4 times a year and doesn't go to sit ins? Their total overall alignment of their actions and their words are probably greater than vast majority of people who also don't even consider emissions from flying but say they care about climate change.

It's legitimate to agitate for change at a higher level while maintaining individual behaviours that align with status quo.

No? They’re literally more hippocritical?

That’s like saying the catholic priest is more aligned with their sermons, even if they’re having random hookups too?

Flying is only 1% of the total emissions

Where’s the line between hypocrisy and an understanding of scale in your model?

You know, I'm not mad at them, and I don't think they're necessarily being hypocrites. I imagine that if they really understood the engineering and chemistry around oil, they would alter either their behavior or their politics.

I'm bothered that anti-oil westerners are unaware of how heavily their existence is subsidized by oil. Every part of life we take for granted exists because of readily available petroleum. Western students are taught the environmental consequences of fossil fuel burning without ever really learning the degree to which every first-world nation in the world relies on petroleum for plastic, fertilizer, fuel for shipping food/fuel/goods, etc. For the record, I would like to divest from oil wherever possible, but I am actually ready to give up many of the modern benefits of the oil-consuming first world. I don't think the people I know who sit in at the banks are.

But "everyone and their dog" doesn't do that. About half of Americans never fly and a quarter fly once a year. Only 7% fly as much as you say or more

Aviation is 2-3% of global CO2 emissions, while not insignificant there are bigger fish to fry

Everyone's favorite thing is a small percentage. Frequent flyers need to sacrifice too.

It also benefits a tiny part of the global population so per user it's actually not that small of an impact.

A reduction in foreign energy dependency is always nice to have. They can also use the geothermal to generate electricity. The carbon savings aren't that much but nearly free energy sources are nice to have.

That should tell you more about the energy intensity of a long-haul 777 flight.

> The temperature of the water in the caverns varies between 50 and 90 °C.

Presumably 50 is in April or May and 90 is in August or September. Or are these swings shorter-term ?

Yea that is one thing missing. Is it seasonal heat storage, or for balancing wind power?

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