Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

newatlas.com

Post reply on HN
Print view View original

111–120 of 192 posts

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#111

Post by tzs »

methyl wrote: post #67
jtc331 wrote: post #64

Earlier quoted context omitted.

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 c…

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

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...

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#112

Post by btbuildem »

Super_Jambo wrote: post #70
arethuza wrote: post #37

Earlier quoted context omitted.

The Grey Dogs channel between the Scottish islands of Lunga and Scarba has a peak flow of about 15km/h with large standing waves - quite incredible to watch this up close and watch the sea shooting past!

And of course some lunatics will go and find a way to have fun in them! Here's a sea kayaker at Penrhyn Mawr off Anglesey in Wales. https://www.youtube.com/watch?v=l5o7qV1Gy04

Looks like fun! FPV [1] and drone footage [2]

1: https://www.youtube.com/watch?v=Qo28x0CYBaA 2: https://www.youtube.com/watch?v=ehN9c7WfLMI

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#113

Post by [deleted] »

methyl wrote: post #67
jtc331 wrote: post #64

Earlier quoted context omitted.

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 c…

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

[deleted]

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#114

Post by bbsz »

kevinbowman wrote: post #65
debok wrote: post #55

Earlier quoted context omitted.

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…

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.

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.

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#115

Post by 7952 »

dylan604 wrote: post #108

When the wind isn't blowing, no wind generation. When the sun isn't shining, no solar. So these guys come in with a "gap" filling idea of using tidal, yet their own marketing says this "kite" parks itself when there is no tidal flow. So how is this continuous power generation?

It's not continuous, but would presumably be very predictable. And times of less movement would be different across the world which makes it possible to have some geographic resilience.

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#116

Post by nawitus »

methyl wrote: post #67
jtc331 wrote: post #64

Earlier quoted context omitted.

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 c…

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

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.

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#117

Post by arethuza »

btbuildem wrote: post #112
Super_Jambo wrote: post #70

Earlier quoted context omitted.

And of course some lunatics will go and find a way to have fun in them! Here's a sea kayaker at Penrhyn Mawr off Anglesey in Wales. https://www.youtube.com/watch?v=l5o7qV1Gy04

Looks like fun! FPV [1] and drone footage [2] 1: https://www.youtube.com/watch?v=Qo28x0CYBaA 2: https://www.youtube.com/watch?v=ehN9c7WfLMI

Here is a video from a boat in the Grey Dogs:

https://www.youtube.com/watch?v=zLFG7x6rrKw

Definitely not somewhere I would want to fall in!

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#118

Post by ComputerGuru »

debok wrote: post #55
tetha wrote: post #14

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 skylin…

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…

(What’s a geyser?)

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#119

Post by coderedart »

ComputerGuru wrote: post #118
debok wrote: post #55

Earlier quoted context omitted.

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…

(What’s a geyser?)

Water heater for bath/showers

Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

#120

Post by m0llusk »

out_of_protocol wrote: post #15
tetha wrote: post #14

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 skylin…

> 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)

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.
Post reply on HN