How to Build a Windmill (2012) • Hacker News Board

Re: How to Build a Windmill (2012)

#21

Post by dotancohen » Sat, Dec 23, 2023, 9:54 PM UTC

onlyrealcuzzo wrote: post #18

cyberax wrote: post #12

Earlier quoted context omitted.

There are commercially available wind turbines, rated for 1-20kW. My partner's parents installed such a system in Oregon, they live off-grid and use it to minimize their propane generator's use. A 3kW system was around $7k in total. It doesn't make much sense if you have a grid connection, the payback time will likely be at least 15 years or so. But it makes sense for an off-grid system.

How many kwh per day does the 3kw system cost? 2 of those could, theoretically, power all of a typical house's electricity if they got anywhere near 3kw on average. $14k to not need the grid would be a deal.

You would need energy storage as well, not to mention spare parts.

Re: How to Build a Windmill (2012)

#22

Post by cyberax » Sun, Dec 24, 2023, 8:32 AM UTC

spockz wrote: post #13

cyberax wrote: post #12

Earlier quoted context omitted.

There are commercially available wind turbines, rated for 1-20kW. My partner's parents installed such a system in Oregon, they live off-grid and use it to minimize their propane generator's use. A 3kW system was around $7k in total. It doesn't make much sense if you have a grid connection, the payback time will likely be at least 15 years or so. But it makes sense for an off-grid system.

What is the longevity of such a wind turbine? How much maintenance goes into it, both hours and money for parts? 15 years is quite a long time.

The maintenance needs to be done about once every two years or so. It requires lowering down the mast and inspecting the bearings. Both are pretty easy to do.

It's a simple system without a gearbox, the only moving parts are the rotor and the brakes.

The turbine is supposed to last for 20 years, and it can probably exceed that.

Re: How to Build a Windmill (2012)

#23

Post by cyberax » Sun, Dec 24, 2023, 8:37 AM UTC

onlyrealcuzzo wrote: post #18

cyberax wrote: post #12

Earlier quoted context omitted.

There are commercially available wind turbines, rated for 1-20kW. My partner's parents installed such a system in Oregon, they live off-grid and use it to minimize their propane generator's use. A 3kW system was around $7k in total. It doesn't make much sense if you have a grid connection, the payback time will likely be at least 15 years or so. But it makes sense for an off-grid system.

How many kwh per day does the 3kw system cost? 2 of those could, theoretically, power all of a typical house's electricity if they got anywhere near 3kw on average. $14k to not need the grid would be a deal.

You won't really be able to power a house consistently with wind turbines because there are long periods (many days) without enough wind. No amount of storage can compensate for that, you'll need a generator or a grid tie-in.

The average capacity factor over the last year was about 30%, and they live in a rather windy location.

Re: How to Build a Windmill (2012)

#24

Post by cinntaile » Mon, Dec 25, 2023, 8:39 AM UTC

cyberax wrote: post #23

onlyrealcuzzo wrote: post #18

Earlier quoted context omitted.

How many kwh per day does the 3kw system cost? 2 of those could, theoretically, power all of a typical house's electricity if they got anywhere near 3kw on average. $14k to not need the grid would be a deal.

You won't really be able to power a house consistently with wind turbines because there are long periods (many days) without enough wind. No amount of storage can compensate for that, you'll need a generator or a grid tie-in. The average capacity factor over the last year was about 30%, and they live in a rather windy location.

If you supplement that with some solar panels and a battery, a generator wouldn't have to run that often.

Re: How to Build a Windmill (2012)

#25

Post by jacquesm » Fri, Dec 29, 2023, 10:31 PM UTC

greenbit wrote: post #2

Especially enjoyed the part where they fabricate a custom 500 watt, 54-pole (if I counted right) out-runner alternator essentially from scratch. Sheet metal was cut!

That was almost as hard as cutting the blades. The tricky part was that the sheetmetal when plasmacut deforms so much and so fast that you have to really move the plasmatorch upwards and out of the way or you'll have a material strike. This required intervention into the guts of the plasmacutter driver to pick up the voltage across the arc which is a good way to gauge proximity. Keep that voltage constant and you're going to be a relatively constant (+- .5 mm) distance away from the material you're cutting. The cutter used was a 12KW Thermal Dynamics unit, it would go through 1/2" like butter, very nice tool.