Comment by david-given | Hacker News Reader

Comment by david-given | Hacker News Reader

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...addendum: there's actually a huge pile of small power generation facilities springing up all over the Western Isles and nearby mainland. But the purpose of most of these is to produce passive income.

e.g. in Applecross on the mainland nearby, they're just finishing installation of a community-funded hydro system. It'll produce 90kW, with an income of about 100k GBP a year going towards the community and small shareholders: http://www.applecrosshydro.scot/

90kW is a toy, though. It's not going to provide energy independence for anyone. Rather more significant is the estate across the loch from my father's village, which is installing 3.5MW of private hydroelectricity: http://www.hydroworld.com/articles/2016/06/gilkes-begins-con...

But a 3.5MW plant, if we assume it runs at 100% capacity for a year, is going to produce 0.02TWh of energy, which is about 2 ktoe (kilotons of oil equivalent). In 2015 the UK used 140000 ktoe, of which only about 20000 ktoe are electricity. (https://www.gov.uk/government/uploads/system/uploads/attachm...)

These systems are important locally, but they're not going to run cities.

Edit: misread one of the graphs, corrected the number above. (The stupid graphs all have lines in slightly different shades of bodily function. Maybe they were trying to make a point.)

> not going to run cities

No, that's the big mostly offshore wind farms. Currently sitting at 12% of demand: http://gridwatch.templar.co.uk/

Energy independence on the personal level is as much of a pipe dream as economic independence. You might be able to achieve it at great expense, but what for? Even on Eigg the islanders are on a little grid.

That's a really cool site. Thanks for linking to it.

...but I do need to point out that 12% of electrical demand is about 1800 ktoe, which is only about 1% of total energy demand. We use about six times more petroleum energy that all electrical demand put together.

That's a tricky/misleading comparison to make since most of that oil energy is lost as waste heat, possibly 2/3rds of it. You really only want to compare the actual energy that makes it through to achieving some stated goal like moving a car or heating a home.

Well, yes. That's the great unanswered problem of the world; what do we do when that runs out or we can't burn it without exceeding safe CO2 limits?

Scotland already went through a period of energy resource shortage in the 1800s when there were very few trees left. Going back to only locally renewable resources might be like that again.

Well, my preferred solution is gigantic offshore tidal power generators in the Minch and around the top of Scotland where there are strong currents, preferably combined with hundred-kilometre-wide offshore wind farms (if you're building power generation structures in the open ocean anyway, you're an idiot if you don't put massive wind turbines on top of them).

Tide is one of the few renewable technologies that generates reliable power, and so is suitable for baseline load. Even in Scotland, the wind drops. But it's had very little investment, partly because of a poor reputation from horrific ecological damage caused by tidal barrages in the past, but mostly because wind is sexier.

But plants big enough to actually make a difference are going to be very, very big. Microgeneration is great for small rural communities, but we live in cities these days.

Here's a new 320MW tidal lagoon being built in Wales: http://www.tidallagoonpower.com/projects/swansea-bay/ These only work when attached to a coastline, though.

So that tidal lagoon... Is it basically a two-way dam that's taking advantage of the height differential between the interior and exterior? That's a pretty cool way to do it. Seems much simpler and more reliable than those wave-powered things that come out in news articles every once in a while.

Its been a while since I worked in the field but I'm pretty sure the main sources of electrical power in Scotland are the nuclear AGR sites at Torness and Hunterston B.

There is a similar electricity tracker at http://energynumbers.info/gbgrid . The main notable difference is that this one adds embedded wind to the window power total. Embedded wind refers to power stations which aren't connected to the metering system so they will show up as lowered demand (the tooltip for wind on the gridwatch site mentions this).

David,

Can I pick your brains about MSP430FR5994 UART code in assembler at some point please?

TIA

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