Best energy storage solution?

Question

I want to build an "off-grid" house, with tonnes of solar panels and wind turbines to sustain a modern lifestyle. The problem is that the sun doesn't shine at night and wind turbines don't move when there's no wind, so I need to figure out a way to store large amounts of electricity for later use. I've looked at the following ideas:

1. Compressed air
2. Pumped-water storage (moving water up to a large pool, then letting it back down to drive a turbine when needed)
3. Flywheel with magnetic bearings, kept inside a low-pressure container.
4. Hydrogen production through electrolysis of distilled water, followed by reuse in hydrogen fuel cell.
5. "Gravity" batteries (suspended weights driving a shaft with connected gear box, like the first clocks ever produced)

It seems like none of these are viable/pracitical/cheap alternatives to chemical energy storage - "regular batteries". So what do I do now? Does anyone know of a better idea?

I do NOT want chemical batteries, as I am a bit of a "closet hippie" and don't want to contribute to pollution.

Answer 1

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Answer 2

The big problem with hydrogen is the amount of energy needed to obtain it. It takes far more energy to separate the hydrogen and oxygen in the water than can be produced by the hydrogen. That's the main reason hydrogen energy isn't popular. Gasoline is found in the earth, so we don't have to make it - just pump it out and refine it. I think that gasoline is still the most efficient fuel for now. However, we're obviously going to run out soon if we're not careful. So I'd probably go with electricity. We already have renewable electricity generation all over the world (solar cells, wind turbines, hydroelectric dams). Hybrid cars, while still in their infancy, have the potential to be extremely valuable. And if, at some point, a battery is invented that has a high enough storage capacity for its size, we may well be able to switch over to purely electric cars. They wouldn't have any emissions, either. Think of this: if a battery could run a car for the same distance as a tank of gas, we could have battery stations instead of gas stations. People would just stop there, get an empty battery switched out for a full one, and the station would recharge the used one for a future customer.

Answer 3

Hey MBB, all of these technologies work, but are only practical on a utility scale. We were faced with the same situation 14 years ago. Our property even has a 355 foot high sand dune, so I tried to work out lifting water to the top. Those systems need millions of gallons and expensive pumps, and you need industrial pipes and fittings since the pressure at the bottom is over 140 psi. In the end we put in a 2200 amp hour 24 volt battery pack. It was made up of golf cart batteries, and cost less than all the other options. Mike is quite right here, lead acid only harms the environment if you dump it someplace. After 12 years we recycled our aging batteries and bought new ones, they paid us for the old ones and all the materials are reused. This really is your best bet for a home sized system, trust me on that.



Our cabin continues to be wind and solar powered today. A better angle is to find alternative generating sources to augment your wind and sun resources. We built a stationary bike using a 24 volt electric scooter motor, and take turns "working out" on it during calm rainy days on our covered deck, good exercise and added electrons. A company in Idaho built a wood pellet stove with an integral thermal heat semiconductor that produces some DC electricity from the stove while it's hot, feeds directly into the battery. Another company in Florida used to make mini steam turbines that can be run off a wood stove. And nothing works quite as well as managing your power. A everybody wants to overpower their wasteful lifestyle with more energy. We simply do certain tasks when the sun shines or the wind blows, like running laundry machines, vacuums, and power tools. Simple changes in living like this can reduce your storage requirements by half, better than any technology you can find. Don't let your bad habits push you into a technological corner, navigate your way out, it's worked for us for 14 years. Use LED lights, low voltage to reduce inverter losses and less equipment, smaller more efficient appliances, fans instead of AC, and so on. We still have modern conveniences here, a TV, laundry machines, deep freeze and fridge. Our array is only 1.7 kW and the turbine is 1 kw. You can make it work too, but stay with the proven stuff everyone else is doing. Good luck, and take care, Rudydoo

Answer 4

You missed one, Horses. They can turn a tread mill to pump water or grind grains. They warm a home if kept in the same abode you live in. When the home has a bit of a chill feed the horse some corn and they heat up. Their waste is valuable fertilizer for raising food. They pull plows and other implements and if you have both sexes they are self propagating. You can even eat them and use their hides for other useful products. At the same time they are a little faster means of transportation than walking and pull heavier loads than a person can. Horses are a lot less expensive than a lot of the other energy saving options. You might even get some wild horses from the west at a very reasonable price from the government. My father back in the 1920s had a mustang that was broken for a harness to work on my grandparents farm.

My father made the mistake of taking off the hackamore before putting on the bridle one morning. For the first time since the horse was caught, it was free. Then it tried biting and kicking my dad in the corner of the stall. My father just kept punching it's nose until it learned better. Then the bridle went on and they went out for a day's work like nothing happened. Horses that have never been wild are easier to use. But my dad said that horse would go down on it's belly to pull a heavy load. It never gave up. My dad was pretty fond of that horse. The horse respected my dad.

Answer 5

It seems that you have already looked into most of the conventional means of energy storage. Have you looked into the "flow" battery concept. Flow batteries offer several benefits over lead-acid or other, conventional batteries. One is that they promise to have a much longer life, the second is that many of the different types of electrolytes that have been used are relatively benign and non-toxic. Also, to get more energy storage, you do not need to build a larger battery, just provide larger tanks to store more electrolyte. These batteries have been very expensive but have been rapidly coming down in price over the years while the technology continues to improve.

Answer 6

Glad you're rich - all of the "ideas" you've brought up have been tried. Some are impractical for home use - the only way pumped water works is having at least 100 feet of head which would be a very strange home site.

And making distilled water takes a lot of energy.

And all of them contribute to pollution in some way - mostly at the place of manufacture.

The real problem is Your goal of "a modern lifestyle" when you are full of ideas for using lots and lots of energy instead of falling back on a reasonable lifestyle that matches the energy available.

Answer 7

You have just tripped over the huge "elephant in the room" problem with renewable energy sources...storage. The French have some tidal power stations that pump seawater into an enclosed bay, then let it flow out via low pressure turbines.



I think you will need to create different systems for different purposes. Heat and cool by means of a thing like a swimming pool in the basement, filled with water and granite rocks, heated and cooled by a heat pump using surplus solar and wind power. Electricity by means of a nearby mountain with a lake at the top, provident high pressure water to a Pelton wheel, and replenished by rainfall, snow melt and surplus solar/wind power.

Answer 8

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''Chemical batteries'' do *not* contribute to pollution - - unless you throw them away or burn them or otherwise pollute *with* them.

A bank of car batteries (or even better - semi-tractor batteries - if you can get them) is a relatively basic, simple method for storing substantial amounts if energy.Have them in a dry storage area, with proper wiring, and its effective, long-lasting, rechargeable and non-polluting.

Entirely off-grid?

No. At least, you will have some maintenance, and eventually (roughly 10 to 20 years) you may start having to replace some.

But if you want the benefits of electricity - well, this is the current best option for the average grid-edger.

Answer 9

Those are all good answers, including Geo thermal, if you choose a rare house location, that is favorable to Geo thermal, such as half way to the top of the South face of Mount Saint Helens. The land will be cheap, so you can invest perhaps $100,000 in solar, wind, and dabble in, gravity, Geothermal, two tiny swimming pools, one about 100 feet higher than the other. Both pools will need to be enclosed to prevent freezing as the temperature will be below zero f perhaps 500 hours per year. Even with enclosures, you may have to drain one of your pools, December to March each year. Possibly one pool can be inside your main living house. It depends on the water temperature you get from several wells up to 1000 feet deep. Deeper is too costly, with typical temperature gains. Purifying the water, to acceptable to your skin and your water pumps and turbines, will not be cheap, even if you think one kilowatt of electricity, when all the other systems are not producing. Batteries are far cheaper = about $1000 dollars for a five kw source, up to one hour, if everything else is down.

Answer 10

If you're concerned about contributing to pollution, perhaps you should think again about solar. Do a little research into what's involved in the manufacturing process of PV panels. Not only is there a toxic waste by-product, but it actually takes more energy to produce a panel than that panel will generate in its whole life span.



Out of the options you've listed, a flywheel bank is probably your best bet. I hope you've got deep pockets, though.

Answer 11

If you want a non-polluting storage system, look at Nickel-Iron batteries rather than lead-acid.

(Also known as NiFe cells or Edison cells).



They have no lead or toxic substances and they the only practical type to have a near-infinite life.



They need servicing every few years (fresh electrolyte, as it slowly absorbs CO2 from the air and degrades), but that is just potassium hydroxide so easily replaced - the actual "plates" and structure of the cells do not degrade.



The "Official" life rating is typically 40 - 50 years, but some have now been in use for around 100 years.



More info:

http://www.nickel-iron-battery.com/

https://ironedison.com/iron-edison-usa-series-nickel-iron-nife-battery

http://ironcorebatteries.com.au/

Answer 12

Use batteries. You are already using solar cells, which are made with some of the most polluting processes in the modern world today; the vast amounts of energy, chemicals and toxic elements needed to produce solar cells will blow your mind.



Batteries are fully recyclable.



It's fine to be a closet hippie, but at least be an educated one - it gives credibility to your lifestyle.

Answer 13

Without using the battery option, none of your idea is working well and too expensive to achieve !

Answer 14

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