Can I store electricity from a wind turbine directly into a battery?

[royp]

TL;DR Summary

Storing electricity from wind turbine directly into a battery

Hello,

This is an enquiry about the wind turbine electricity and battery storage. I am framing it based on my limited understanding. Please advise me.

I intend to install and capture the wind energy through a small wind turbine at my home. The turbine shaft will be directly connected to the alternator (AC generator). As the alternator produces electricity, as and when, and at variable rates, it will be directly channelled (electricity) to a battery storage;instead of supplying to the grid. The battery will be subsequently used to power home appliances.

Can it be done? There will be no gearboxes/speed governor etc. to ensure a specific frequency. (There will probably be an AC to DC converter needed). Will this simple set-up work without failing?

Many thanks in advance

 

[anorlunda]

Yes our can be done. Thousands of cruising boats around the world do that.

However, it will work better if you use DC generator to charge the battery, then an AC inverter to convert DC to. AC for appliances.

Your first step should be to figure out your electrical energy needs and probably to reduce them to fit the capacity of your wind turbine. 1 kWh per day is good number for a small wind generator.

Also you need a plan for what to do on days when the wind does not blow. You can use grid power on those days. However you can not connect your appliances tio both the grid and the inverter in parallel. If you need both it is more complicated and you must contact your local power company to learn how.

Good luck.

 

[royp]

Great and clear explanation, anorlunda! This is eminently useful. Many thanks.

 

[sophiecentaur]

Summary: Storing electricity from wind turbine directly into a battery

Hello,

This is an enquiry about the wind turbine electricity and battery storage. I am framing it based on my limited understanding. Please advise me.

I intend to install and capture the wind energy through a small wind turbine at my home. The turbine shaft will be directly connected to the alternator (AC generator). As the alternator produces electricity, as and when, and at variable rates, it will be directly channelled (electricity) to a battery storage;instead of supplying to the grid. The battery will be subsequently used to power home appliances.

Can it be done? There will be no gearboxes/speed governor etc. to ensure a specific frequency. (There will probably be an AC to DC converter needed). Will this simple set-up work without failing?

Many thanks in advance

One word of advice before you launch into a project like this. The output of small wind turbines is laughably small - enough to trickle charge the batteries on a boat and to provide DC power for electronics on an irregular basis (hence the batteries).
As @anorlunda says, you should be thinking in terms of a proper, commercial alternator with internal rectifiers which would give you, probably, 12V. You need some regulation to cope with variable wind speed to keep your battery bank happy (all obtainable).

For mains AC home appliances you would need an Inverter system to convert your DC. You couldn't mix the home brew with the mains unless you pay for some very expensive equipment to sync your AC with the mains AC. That needs to be approved by your supply company. That means you would either need a separate circuit into which you would plug some of your home appliances.

Have you done any research into the likely power output of the sort of turbine that you could instal at home? Look at your electricity bill and see how many kWh you use and see what sort of proportion of that any practical home turbine could give you. It's down to raw economics and 'the sums' and, unless you have vast resources of money (and wind) you are unlikely to get much payback unless your circumstances are pretty unusual. (You may be lucky, of course)

Also, did you consider Solar PV panels? They are good value in many parts of the world and you can get turn-key installations that can actually pay you back within in a couple of decades.

Do a lot of homework on this to get a proper idea of what you can do at your location.

PS A small project to provide LED lighting in outhouses and standby lighting in the home would almost certainly be suitable for 'fun'. I did just that with a PV panel supplying my shed and summerhouse lighting. Very satisfying to find it had the right capacity for the requirements - and it still works fine.

 

[gleem]

My experience with wind turbines is on a boat. At anchor I generally could not expect more than 0.5 kw-hr/day from a turbine with at 250 W max output. It was mounted about 4 m above the water line. Higher would have been better but it was not practical. I could reliably get 1 kw-hr/day from my solar panels(270 W).

I do not know where you live (US?) but you should find out your average wind speed at your location before you decide to buy a wind turbine. This website shows the average wind across the US

https://windexchange.energy.gov/maps-data/325

If you live in the US east of the Mississippi and south of the Ohio river unless you live at a high elevation the average wind is generally less than 10 mph at 30 m. Ten mph is about the minimum wind speed that produced substantial current for my installation it was about 4 amps at 12 V. At 20 mph the output was about 18 amps. The turbine was more useful underway where the wind was usually substantially higher for longer periods than at anchor.

I agree with Sophiecentaur that you should consider solar panels with at least the same power output alone or as an auxiliary source. They may even be cheaper than a similar wind turbine. When the sun shines the wind is often down but when it is stormy you often see more wind.

The battery will be subsequently used to power home appliances.

I assume the batteries are for emergency purposes. You need to consider how long you will need to use them and determine your expected power use during this time. As far as appliance are concerned you may not use any heavy duty electrical appliances as a dryer , stove or any heater at this time. One 220 amp-hr Li battery could give as much as 9 hr with a 300 w usage . A standard deep cycle lead acid battery should only supply about half that . Drawing too much from a Lead Acid battery substantially reduces its life.

 

[sophiecentaur]

@gleem That's interesting info. What was the diameter of your turbine?
This link shows how diameter affects the power out from huge turbines. You can search for equivalent figures for home scale arrangements. The power out is (sort of) proportional to the swept area so 2.7m diameter blades would produce 2.25kW max. Mounted in a sub optimal place, it could go down drastically, as @gleem has mentioned. I remember several years ago B&Q (a UK DIY store) were offering turbines for the home with about 1kW output but that was advertisers speak!

 

[anorlunda]

Does it make sense for us to speculate without knowing the scale the OP needs?

@royp , can you tell us more about your requirements. We need to know your power and energy requirements. Also your budget, 1000 €? 1000000 €?

 

[royp]

Hello All,

Many, many thanks for such rich and thoughtful replies. I am currently residing in UK, not US. My enquiry, to be very frank, was a kind of 'laboratory situation' which essentially asks whether erratically and irregularly blowing wind can generate usable (via battery) electricity through a turbine.

As sophiecentaur rightly said "The output of small wind turbines is laughably small ...".

The main application I have in mind is a motorway(UK). To place suitably designed VAWT on the side of the road - every 10m or so apart and get the energy from the thrust of the very fast moving vehicular traffic. But (with my limited knowledge), I was not sure whether electricity, thus produced, can be usable. Though I have experience of powering light by a bicycle (irregular movement) dynamo in my younger days, the knowledge was not very sound.

Now, Please share your valuable opinion on how practical is the scheme - especially on a larger scale.

 

[anorlunda]

That clarifies a lot. It is unfair to make us guess, and it discourages people from investing their time and effort to provide good answers.

Sorry, but that idea for vehicle powered wind at the roadside sounds horribly complicated compared to solar panels. Beside that, it probably would not work at all. The blades need to spin continuously, not in surges.

 

[sophiecentaur]

that idea for vehicle powered wind at the roadside

Absolutely. It's just one of those 'Energy Harvesting' ideas which are attractive when you first think of them but very rarely can be economical. Moreover, in most systems, to get a significant amount of power out, you actually get it from the passing vehicles or peoples feet etc.. Details are so important and the Public would complain bitterly if someone ever suggested that their mpg was being compromised by Energy being stolen from them.

 

[royp]

Sincere apologies if I have (absolutely unintentionally) misled my fellow members through this post.
anorlunda: the title asked the viability of storing wind-turbine electricity directly to the battery and your (very first) response was quite adequate for me. But there were more detailed and thorough explanations which are obviously most welcome but that also prompted me to state the second 'part' of the enquiry. The 'roadside energy harvesting' idea was still very sketchy but I needed to clarify the fundamentals of the battery storage first. And that was the idea about the post.

Many thanks, nonetheless.

 

[sophiecentaur]

The 'roadside energy harvesting' idea was still very sketchy

Don't spend too much time in trying to fill in that sketch. About the only place I can imagine significantly moving air due to moving vehicles would be in an Underground Railway Station and even that's a bit feeble, despite lasting for quite a few seconds. When a passing truck feels as though it's nearly knocked you over, that doesn't represent many Newtons or metres.

 

[royp]

Thanks, sophiecentaur./

 

[MM Engineering]

Hello All,
Mostly, Electrical batteries are used in solar energy equipments and applications. These batteries can be used to store the power generated by wind. Lead acid batteries are the suitable choice to store electricity as they are well suited to trickle charging and high electrical output charging efficiency.