why does the energy take so so so long to regen there should be tokens you buy with crowns and then you double click the token for energy,certain crowns for certain energy numbers
how to get energy

Just check the Wiki (link at the top) to read about energy.
Anyways, your post sounds like a suggestion, so it should be in the suggestion forum (not that it would be any more popular there).
The bottom line is: It's important that Mist functions as it does to encourage players to pay money so that the game developers can afford to live in a house and provide food for their families. If you want to play more, you either have to pay money or, once you reach Tier 2, you can do certain clockwork missions that give you more crowns than the energy you spend to do them. In this way, you can use Crystal Energy to do levels pretty much indefinitely.
The way they currently do energy is horrible. Instead of making us buy energy piecemeal (which I will never do as it is only a one time usage per payment. If I wanted to play without interruption I would be paying a LOT of money.) they would do SOOOO much better to offer a monthly subscription to get unlimited mist. For this game $7.95 a month sounds about right. A fixed price model always earns more money than the piecemeal system.

Have you heard of the "elevator pass"?

Apperently the guy above ai-hina has never heard of an elevator pass. Which one is cheaper than 7 dollars and two better because you don't have to pay. Idk if you new this but this game is f2p

To earn more energy you have to sells mats or do some missions if you earn alot of crowns then you just wait to drop down the cost of energy that you can save more crown and energy
i can't buy crystal energy so a free way to get energy is a valid conundrum.i have no credit card and my mom doesn't use her debit card on games.so unless you can use an ultimate game card there is no way to get more .

"there is no way to get more ."
Yes, there is. Bottom right hand corner of the screen is your energy, there's a symbol on it, click that. It will bring up another window, click on trades. From there, you can opt to either buy 100 CE with crowns or sell 100 CE for crowns.

The elevator pass is 6.95 not 7.95.
Convince your mom playing here is cheaper than the dollar or two you would put in a game at the arcade and tell her it lasts all month instead of a few minutes. You could also try, it's like buying a game for a console but environmentally friendly because it doesn't come with all the wrappings and plastic you get with store bought games. :)

you guys realize this thread is from september, right?
Have you heard of Crystal Energy? No? Please do your research before making a suggestion like this. We don't need threads like this where completely new players ask a question that can easily be answered by a little effort on your part.