Visit the forum instructions to learn how to post to the forum, enable email notifications, subscribe to a category to receive emails when there are new discussions (like a mailing list), bookmark discussions and to see other tips to get the most out of our forum!
"open source" grid-tied wind energy?
  • Hi All -- happy to be here and looking forward to discussions.

    Just moved to an acreage with rolling hills and lots of wind. A few of the neighbors in the distance have windmills and I'd like to get one going to supplement/augment my electrical power usage.

    I see kits and plans for building battery-based wind energy installations....but I don't want to mess with batteries at all. I'd prefer to tie into the grid and push my produced power right back in to run my meter slower or backwards.

    Are there any ideas/options for kit-based grid tied systems? Anyone have any ideas?

  • 9 Comments sorted by
  • I don't know too much, but from what I have seen, plugging into the grid seems to make a lot of sense. It is like having a big battery that pays you to not use it.
  • I have a had this idea in my head for many years. There are many ways of storing energy. For instance, you could pound heat into a large water tank stored under you home's foundation. You would take the power you're not using and divert it into what is called a Dump Load. In this case it's a simple heating element. This energy would preheat the water going into your hot water tank for instance and save you money. It would keep your home warm also.

    But my original idea was to store energy mechanically. You could used the surplus energy you have to run a hydraulic pump. This pump would slowly lift a very heavy weight mounted on a tower. This potential energy could be used by reversing the process. You would let some fluid out under high pressure to run a motor connected to a generator. Bam! you have energy on demand. That weight can stay up there for months on end and never move, ready to be used anytime. This sort of structure would be very long lasting. Decades before any major repairs would be needed.

    Batteries on the other hand have leakage currents that constantly rob you of energy. They tend to lose their efficiency as the years go by. And you're lucky to get a decade out of them before they fail. Not to mention all the environmental issues surrounding the technology involved in creating the battery in the first place.

    Now I suspect that the numbers would show some pretty low efficiencies involved in the hydraulic process. I think it still is a real winning idea when you take the whole picture into account. A systems perspective if you will.

    Just me rambling....:)

    The Dawg
  • Lifting a heavy weight on a tower wouldn't store enough energy for the cost.... however using a windmill to pump water into a large resoirvoir to create an artificial dam is often used to even out the ups and downs of wind power. You can store truly massive amounts of energy that way and the cost per stored watt goes down as you scale up. (it perhaps is not as effective at smaller amounts without some natural hillslope or something to take advantage of to make a natural dam) The efficiency of it can be some 85% efficient if I remember right, it basically turns wind power into hydropower.
  • Jerry,

    That is how they do it in Germany; to store excess power when wind and solar are making too much for the base load on the grid.  Another way is to compress air into spent underground gas fields.  You lose some energy, but when you have too much it is better to store some instead of none.

    I think that one cubic meter of water dropping one meter can make 1kWh.  So either an elevated reservoir (on a hill or mountain) or a surface reservoir and an underground generator and tank.

  • Vote Up0Vote Down
    December 2011
  • I think any mechanical means of energy storage isn't going to be feasable unless you only want to store a kilowatt-hours...   Even then it's going to take quite the construction set up to get there.   I think batteries are the only feasible solution really at this point.  Heating a pool of water under you home or something of that nature would be fine during winter months, but summer wouldn't be so "hot" lol.. 

    I don't like grid tied stuff simply because I don't want someone else telling me how to do it... you have to have certain grade equipment that produces a certain type of sine wave.  It has to be a pretty sophisticated piece of equipment and those are generally expensive as well... I'm seriously thinking about converting my homes lighting over to  LEDs and wiring the house with low voltage/amperage DC systems.  Just eliminating the AC lightbulbs would be a large energy reduction.  
  • Vote Up0Vote Down December 2011
    If I understood you correctly you need some sort of software which does the distribution and data acquisition automatically. I know some guys in Kosovo (via the Rochester Institute of Technology) who are working on pretty much such a project, they even want to open source the software. They call the project Kosovo Wind Gardens. They talk about their open sourcing strategy at 1:10.
  • Grid-tie is by far the best choice in the early phase, unless you have no grid (nearby). On a village scale and with accessible-tech (i.e. tech available through GVCS), pumped water storage is the simplest, cheapest, and best choice, if your geography supports it.

    But anyway, wind power is a very good approach to independent power on the village scale. I argue the scale of the turbine should be at least 5-10kW per turbine for primarily power production (except in early phases). A village of 200 people with all the industry needed to sustain itself is going to need at least 1MW of wind power (probably 250kW of constant power, 1MW peak), plus a way to efficiently store that power. That's a lot of power, for sure! That's about one 5-10kW wind turbine (which is pretty large for a homebuilt turbine) per person, but that should be enough to provide for a comfortable amount of electricity for all the uses. (Stored biomass is required for mobile power and for long periods of low wind or drought, wintery conditions, etc.) Here's an example of something that could be relatively easily produced with the standard GVCS machines: The kit for the 10kW wind turbine (tower not included) is ~$8000. Maybe a little larger (logarithmically speaking) would be a sweet spot, like a 20-40kW machine so that you could do only ~30 of the wind turbines instead of 100 of them. Even so, this is likely to be a very difficult project, and some people will probably have to be devoted to producing and maintaining these wind turbines.

    I'm not so sure producing one's own batteries is that feasible with just the tools of the GVCS. I don't see a chemistry lab or metallurgical lab on the list (though surely some will be needed anyway).

    An electric tractor using a long electric cord, as tacky as it seems, is likely the most efficient (and realistic and sustainable) solution, and is practiced by many small (organic) farms today.

    Another point is that at some point, the GVCS is going to need a small Fischer-Tropsch capability (using the output of a wood gasifier, already part of the GVCS) to make the electrical insulation, synthetic rubber (milkweed or dandelions would work, but getting it in the quantities needed would be ridiculous), thermoplastic for 3d printing, various lubricants, and emergency fuel. And a chemistry/metallurgy lab will be needed for getting the catalysts just right and getting the material properties of the various substances produced (lubricants, etc), etc...
  • Fwiw, 1 kg dropping 1 meter is about 10 Joules (a Joule is a watt*second or one Newton*meter and 1kg*g=9.8m*kg/s^2 = 9.8 Newton*meters = 9.8 Joules = ~10 Joules), so 1000 kg (ie one cubic meter of water) dropping one meter is 10000J or 10 kW*second. There are 3600 seconds in an hour, so it takes 360 cubic meters of water falling 1 meter to equal one kWh. Or, a 5 meter per side cube of water falling ~3 meters. You need a large reservoir. Say, at least 10MWh for a village. So, That's like a 1 acre pond ten meters deep falling to another that is 100m below it or a 10 acre pond just as deep falling just 10m. Not small, but that is for 200 people.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Login with Facebook Sign In with Google Sign In with OpenID Sign In with Twitter

In this Discussion