[tetha]

Since the number 1.2MW didn't mean much to me, modern on-shore wind turbines seem to supply 3-4MW and offshore ones 8 - 12MW.

But this seems a lot easier to transport and install compared to cranes and the nightmare of navigating turbine blades on trucks through places. And if these hold up to water and don't cause too many problems for wildlife, there would be a lot less discussions about these "messing up my skyline", while tapping a new source of energy.

Quite interesting and cool.

[out_of_protocol]

> too many problems for wildlife

There were a meta-analysis regarding population of birds in areas with/without wind turbines, found no statistically significant difference (unlike coal, where difference was huge)

[m0llusk]

Like much statistical analysis there are some details that might not be well captured. Much of the opposition to wind power based on bird deaths is caused by the Altamont Pass facility which is placed in a golden eagle breeding area and has significantly disrupted that species. There could be similar risks here if generating equipment like this were to be used in sensitive marine habitats such as the Monterey Bay. It will probably be worth ongoing study to avoid potentially serious problems that broad statistical analysis may not catch.

[jtriangle]

Yeah, if you're looking to save the birds, the first order of business is to ban cats, because turns out those cute little guys are rather adept at bird murder.

[morkalork]

Apparently that isn't true and just shifting the blame away from the pesticide and agricultural industry which have decimated insect populations. Which are the food source for many birds. Much like blaming consumer's personal choices for CO2 emissions.

[bjourne]

"We estimate that free-ranging domestic cats kill 1.3–4.0 billion birds and 6.3–22.3 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals." https://www.nature.com/articles/ncomms2380

[amenhotep]

This is the first time I've seen the statistic quoted with the distinction that it's about feral cats, and it makes a heck of a lot more sense now than it did when I had the impression they were saying the cats I've had, which were on the whole utterly useless at catching things, were secretly massacring birds by the dozen. Thanks for the drive by enlightenment :)

[Tiktaalik]

It's an apples and oranges sort of issue here.

I have no doubt that stray and feral housecats in the cities and suburbs are killing great numbers of common house sparrows, but the things that are driving down numbers of endangered birds in rural and remote areas (where feral cats are not a problem) is habitat loss and the decline in food sources (ie. berries and bugs).

[tga_d]

Feral cats are extremely common in rural areas (though not in remote areas). Ask anyone who's lived on a farm or ranch about "barn cats".

Regardless, "the single greatest source of anthropogenic mortality for US birds and mammals" sounds unambiguously not great, even if they're mostly not endangered.

[orbital-decay]

How significant is that number? Is it large or small? How much of it is offset by larger populations of well-fed birds and rats in cities? In many countries, people specifically feed stray cats to keep cities rat-free, and predatory birds are often used for pest control (huge crow flocks terrorizing parks etc).

[bronson]

What isn't true? https://www.sciencenews.org/article/cats-kill-more-one-billi...

Yes, pesticides are also an issue.

[carlosjobim]

I've never seen a cat kill an eider or goldeneye.

Offshore wind turbines kill and disturb specific species of birds. Grouping all birds together is of no use.

[tetha]

Yep. I mostly meant for or rather caused by this kite. I wouldn't expect it intuitively, as it's just a big object in the water, not moving erratically or obstructing anything.

[imzadi]

It has a 39-foot wingspan and moves in a figure 8 pattern on a seabed tether. There's going to be at least some implication for local wildlife, but is it worse than the impacts of fossil fuels? I have no idea. It's definitely an interesting concept. I'm sure it will get more efficient and require a smaller footprint over time, assuming we invest in it.

[duskwuff]

> There's going to be at least some implication for local wildlife, but is it worse than the impacts of fossil fuels?

For that matter, how does it compare to the local impact of other watercraft?

[thfuran]

I guess erratic is in the eye of the beholder, but it's certainly moving.

[Cthulhu_]

If tidal energy takes off, I'll guarantee you that - if it hasn't already happened - there will be chilling articles about dead fish and other sea populations.

[tomtomtom777]

It is also a completely different scale. A 11M wind turbine has a 200m (!) rotor diameter. This thing is 12m.

[thfuran]

But it's moving around through some larger area.

[jabits]

Actually, these seabed moorings can create rich, local eco-systems. I know local fishermen here in Maui are drawn to areas around the off-shore buoys...

"The FADs are located 2.4 to 25 miles offshore and in depths of 80 to 1,510 fathoms." -- https://www.lahainanews.com/sports/local-sports/2016/05/19/s...

[debok]

A kettle uses ~1.5KW, a geyser ~2KW, an oven ~5KW, a stove about ~3KW. These are fairly high estimates I got from some quick googling. If you add these all up, and account for some more appliances (HVAC, fridge/freezer etc.), I think it is safe to estimate that a household less than 20KW at peak, even though it is a fairly high estimate.

So going backwards from there, 1.2MW = 1200KW and 1200KW / 20KW = 60 households at peak usage. Which is a very conservative estimate.

For future reference I will use 1MW = 50 households as a conservative rule of thumb. Maybe 100 households per MW is closer to reality, but that feels fairly lenient to me.

[jtc331]

If the average home was using 10kW constant it be using 240 kWh a day, which is enormously high.

In terms of average usage an average sized home in the US is much closer to 50kWh a day, so roughly 2kW average demand. That would mean 1 MW is enough for 500 homes on average. The one thing that doesn’t is peak demand load, say when everyone gets home from work and turns everything on at the same time or a particularly cold or hot day.

Edit: the average US home uses just shy of 1000 kWh a month, or just over 30 kWh a day.

[methyl]

I’m really surprised by this data. In Poland, it’s around 2000 kWh/year, which is 6kWh/day - 5 times less!

[tzs]

According to to stat.gov.pl [1] the average Polish household uses ~24.6 GJ of energy annually per 1 inhabitant. That's 6800 kWh annually per 1 inhabitant.

According to eia.gov [2][3] the average US household uses annually 56.6 million BTUs of natural gas and 10500 kWh of electricity. 56.6 million BTUs is 16600 kWh. That would bring the total to 27100 kWh.

But wait...the Polish data is per inhabitant. The average number of people per household in the US is 2.6. Dividing 27100 by 2.6 gives 10400 kWh. Alternatively, the average Polish household is 2.47 people, which would give Polish per household usage of 16800 kWh.

The US does appear to use more energy per household (total or per inhabitant) than Poland, but by a factor of about 1.6, not 5.

[1] https://stat.gov.pl/en/topics/environment-energy/energy/ener...

[2] https://www.eia.gov/todayinenergy/detail.php?id=57321

[3] https://www.eia.gov/energyexplained/use-of-energy/electricit...

[Taek]

Thanks for breaking this down cleanly and providing sources! Greatly appreciated!

[Symbiote]

The USA includes many places where air conditioning uses electricity, and some places where heating uses electricity.

They also have huge and inefficient appliances, but that's probably a smaller impact on the figures.

[nawitus]

Finland is probably like 15000 kWh/year/house (for a new house more like 10000 kWh/year). All the heating of the house & water is done by electricity, though.

[wongarsu]

Air conditioning makes up a big part of that, made worse by worse insulation and larger houses.

Of course Poland needs heating, but that doesn't show up in Electricity usage as most people heat with natural gas or oil.

[Detrytus]

Actually, most people would heat with coal. Natural gas and oil are far less popular.

[mndgs]

8.2 kwh/day for a household in Lithuania, neighbours Poland. Sounds about right.

2022 stats: 3.289 TWh during 2022 consumed, 1.1M households, do the math...

Source: https://www.lrt.lt/naujienos/verslas/4/1887046/litgrid-60-pr...

[gambiting]

Ok, but what do you actually use? I have a very small 3-bed house in the UK, and over the last few months we've been averaging 1100-1200kWh of electricity per month(and we heat using gas, although we do have an electric car).

[methyl]

It's not me, I'm talking about average for Polish houselhold

[BizarroLand]

Last month I used 1402 kwh in Washington State, which is high for me.

2600 sq ft home kept at 71f, electric heat pump, & heat pump water heater, but I had a few holes in the walls for several days due to repairs during the coldest month of the winter so far which messed up my average using electric heaters to backfill the gap.

Obviously, the holes were covered over when not being worked on but it wasn't as air tight as compared to buttoned up and fully insulated as usual.

My power consumption is usually 30 to ~75% of that depending on weather and activity.

[kevinbowman]

Also relevant, houses aren't boiling a kettle and running their oven 24x7, so this is more like worst-case peak load and will be spread across different houses. Having some kind of battery storage closer to the houses will help a lot - the tidal generator can run fairly constantly and fill the battery, and the houses can draw in short bursts from the battery.

[bbsz]

Yeah. I always feel that the solution for clean and abundant energy globally is to start with better energy grid management (and storage). There's already so many fit-to-all-geography solutions available. It's just that current grid is used to supporting lines centralized around big energy plants and not small producers.

I also always feel that there's a lot more to take down from energy consumption per household by simply making more efficient devices (especially for heating and cooling). It's possible that modern AC/heaters are already close to the peak electrical efficiency, but I guess even better producer standards for things like insulation, thermal conductors or precision sensors could still squeeze something out of the nation-wide usage.

[bagels]

There is synchronized kettle use and toilet use around televised sports games.

[tremon]

So advertising is one of the biggest factors in determining the required grid capacity? Perhaps we should charge them for it.

[Sammi]

Minesto CEO is quoted in local Faroese news saying 800 households:

https://kvf.fo/greinar/2024/02/09/drekin-framleidir-nu-strey...

https://kvf.fo/greinar/2024/02/09/minesto-og-drekin

[TotempaaltJ]

> The current national average (through Q2 2022) of homes powered by a MW of solar is 173.

https://www.seia.org/initiatives/whats-megawatt

[pappn]

I think 100 households per MW in milder climates is very conservative.

Anectdata: I have a ~150 square meter, 50 year old house heated by electricity and heat pump. I live I Norway, and where I live winter temperatures usually don't get lower than -12C. I have 2 EVs that are driven around 50k km a year combined, charged at home every night, simultaneously.

I peak out below 15kW (1h average). That number is deliberate since I get a higher tariff if I go above 15kW. I have some minor smart house installations that most significantly cuts power to my hot water heater if I get close to 15kW, but even without that I would rarely get above 15kW, and never above 20kW.

Average power this January was 4.75kW, December was 4.96kW, August was 2.25kW.

(Edited for typo)

[ComputerGuru]

(What’s a geyser?)

[ragebol]

From top of my head: my grandma used to have one. There was always a little flame running for safety in case of leaks, but when she used hoy water, I think the geyser just heated it on the go, instead of preheating a reservoir.

Could be wrong though.

[tremon]

A device for heating water on-demand, usually a gas burner with a spiraling water pipe surrounding/above it. As opposed to a boiler, which pre-heats water and stores it for later use (and also needs to keep reheating the water as it cools if not used).

Spanish wikipedia is the only with a picture of the internals: https://es.wikipedia.org/wiki/Calentador_de_agua_circulante?...

[mercutio2]

In the US, this is called a tankless water heater.

I’m not sure where in the world calls them geysers, but I agree it’s not a term you’ll hear in the US!

[coderedart]

Water heater for bath/showers

[aqme28]

A common blocker for offshore wind is people* complaining about seeing wind turbines on their formerly immaculate horizon. These don't have that problem.

*: e.g. Ted Kennedy. Rich and politically connected people like to live on the coast

[rootusrootus]

What's interesting is that we can stop off-shore wind projects for that reason, but can't seem to stop the advertising barges that run up and down the coastlines.

[justsomehnguy]

> In April 2022, Minesto announced a detailed plan for large-scale buildout of tidal energy arrays in the Faroe Islands. The large-scale buildout plan sets out a stepwise installation of tidal kite arrays, each with 20-40 MW installed capacity, at four verified locations.

[rootusrootus]

> modern on-shore wind turbines seem to supply 3-4MW

That sounds like the very largest of the most recent wind turbines. I think most of the in-production wind turbines people are used to seeing these days are closer to the 2 megawatt range.

[philomath_mn]

Another reference point: the coal plant in my area outputs 2.3GW. It would take almost 2,000 of these tidal kites to match that output.

I just don't understand why we spend so much time and money on renewables like this when Japan has an 8GW nuclear plant. If the US focused on building these en masse then we'd be in a great place.

[someuser2345]

Because a lot of people hate nuclear energy, and don't support building new plants. So it's not really a choice between nuclear and renewables, it's a choice between renewables and fossil fuel power plants. Besides, I think there's definitely a benefit to decentralizing the power grid, and to learning how to tap different energy sources. I imagine that there are places in the world where nuclear is not appropriate, but tidal energy is abundant.

[philomath_mn]

> a lot of people hate nuclear energy, and don't support building new plants. So it's not really a choice between nuclear and renewables

I guess that is my point: the hate is counter-productive. Neglecting nuclear was one of the biggest blunders of the 20th century.