I'm going to say this about the deck: this is actually a really cool, and maybe even really good, idea.
I've never considered breaking
Energy Field by throwing it in a prison shell. Most attempts with playing it have been "Let's put it in a Brainstorm deck." I'm going to say, you're absolutely right, here, you want something powerful like Energy Field to be inherently useful, not just useful in a specific situation (only with RiP in play).
So, just to clarify, what I like about this deck is that it uses a prison style way to get ahead - Prison permanents - and that playstyle inherently synergizes with Energy Field, which hates Instants and Sorceries. So: max out your Enchants and Artifacts that do stuff. I'll be honest, I haven't seen anyone take this approach with Energy Field.
I wouldn't goldfish this deck just yet. I do have a couple concerns. Like I said, my strength is actually building manabases. This is what I notice about yours: I don't think you have enough color fixing. If you want to run "splash" colors (ie W1, as opposed to WW) I go off the #s in Tempo decks, specifically for Blue, their main color. So I try to stick to about 14 sources if I want to run things like Rest in Peace, Ghosty Prison, etc. At a minimum.
For cards like Elspeth/Jace TMS, that are color intensive... it's more complicated, of course. Maybe look at Miracles (Counterbalance, Jace are both UU). But I think it really only takes something like 17 sources, and you stand a really good chance of casting your UU stuff mid-late game.
I'm going to make a HORRIBLE suggestion, but these cards are technically legacy-playable:
Azorious Signet and
Talisman of Progress. Or whatever the UW Talisman is. These might help, but why I don't like them is that they only mana-fix, and don't make great top-decks, unlike Tolaria West, Wasteland, etc.
Also, and this hurts, but
Mox Diamond could be
Chrome Mox instead. You want U and W, yes, but you also don't want to kill your own Energy Field. This is a "playtest them both" kind of moment. Also, Chrome Mox goes toward your land count, and Mox Diamond doesn't, because you don't recur the lands you discard.
And lastly, also about the manabase: Sol Lands obv work best with artifacts. They also work really well with casting costs like
Ghostly Prison and
Propaganda. This is the main reason Stax manabases run
Chalice of the Void - this is the most powerful card at CMC 2 you can cast in Legacy. It just happens to be a Prison piece. A big part of your deck - Enlightened Tutor, RiP, Energy Field - don't benefit from your Sol Lands. This is something of a smaller point, but consider that if you're sacrificing City of Traitors or taking 8 dmg from Ancient Tomb that you don't need to set yourself back with this kind of manabase.
That said, I think you've got a really great idea here, and even in a Stax manabase, you're right: you don't need to run Chalice of the Void. Experiment the sh!t out of this deck.
I think the easiest way to break Energy Field, with almost no real effort, is to retool Enchantress (which runs almost all permanents, anyway) and jam some # of copies in there. I think your rough build here, though, also deserves a shot and may find it's even more powerful than in Enchantress, and could make it powerful enough to define a new deck.
Some minor spell choices - Ghostly Prison doesn't protect Jace or any planeswalker. (I know, Fred_Bear reminded me, too, haha.) Neither does Energy Field - a dead Jace also kills your Energy Field (big reason why UW Miracles decks stopped running Energy Field). Just swap JTMS with
True-Name Nemesis, though... and I think you're onto a powerful new strategy. Maybe even a Jitte, too.
Terminus - maybe make it Moat / Humility? Again, this deck doesn't really like Sorceries and Instants. But it does want something like
The Abyss. Or
Porphyry Nodes
Or maybe make it a Jitte for TNN. SFM is easily killable, but you might also Tezz the Seeker for Jitte, and for your Helm, too. Just throwing stuff out there.
This is pretty exciting, though! I hope these things I've noticed about your deck helps you brew it!
EDIT 1: Didn't spell Poryphyry Nodes correctly
EDIT 2: Porphyry Nodes is literally impossible to spell