This is a basic skeleton on which I would build the story around. A group of disgruntled Russian supremos decide the time has come to utilise the electromagnetic technology that they possess and so team up with Black September – a well-funded, low-lying Palestinian terrorist organisation (1972 Munich Massacre)– to neutralise the US and take political and economic control of western Europe. They seed the Us and Europe with strategic electromagnetic devices, and then hand the Americans an ultimatum - abandon Europe to the Russians, or see it's entire electronic infrastructure destroyed by a single electronic wave, that would cause untold chaos and destruction. (Electromagnetic technology is real. Black September is a real organisation) What do you think?
A story concept means nothing. I can tell you now, it has been done before. What matters is how you write it, the characterization, the flow, the imagery, all of it. There's no benefit in asking what other people think of the concept! They'll either say,"Sounds great," or, "it sounds like a ripoff of..." If the idea stirs you, write it. Then ask people what they think of the final story. After they tell you what they don't like about it, revise it, usually several times, until you're happy with it or until you throw up your hands and say the hell with it. Please read this thread about What is Plot Creation and Development?
What you have here is a setting- a backdrop. There is something big that is going to happen and it will be important and dangerous and people might die (ohmygod). Characters, people. Characters. Stories work because characters do things. This is a fairly decent backdrop for some high-tension action-movie hijinks. But it is only barely a story. The story isn't about this and shouldn't be about this. The story could be about John O'Friday, a reluctant member of Black September, sent to plant one of the electromagnetic devices. He realises how close it is to a hospital and decides to disable it and all the rest of them, while still tagged as a fugitive by the law. The story could be about the dashing hero Blast Lampjaw-McFistbasher, who is in a race against time to stop the countdown before the cacklingly insane leader of Black September, Zoingo Spangle Rammstein, not only detonates the EMP wave, but also drowns Blast's pet weimeraner Pip in a bowl of cold chili-beans. The story could be about Mary Weathers attempting to lose ten pounds by the end of the month in the middle of a full-scale calamity. But it isn't about the EMP thing. That's just backdrop.
Please don't make it about a group of disgruntled Russians. Unless you have some amazing motivation based on realistic characterisation. Otherwise it'll join the legions of cliche alternate-universe Cold War paperbacks sitting in airport bookshops. EM is all good. But just ask WHY...
If I may suggest an alternative, why not try and mix it up. This idea sounds a little bit TOO much like Red Storm Rising for comfort. Ya know the "Flimsy pretext for Russia to try and take Europe while distracting/threatening America not to intervene. Luckily a plucky young commander does something to beat the Russian superweapon." Instead why not try and add some moral ambiguity? Maybe the ones planting the devices are Americans or Chinese or some sorta combination of the two.
As long as you can make it unique and not like a stereotypical Cold War book, you should be fine. Any idea will work if you make it your own! Good luck!
It is an idea, nothing more. Characters and how they react to the crisis are what sells it. I'm betting you can't get three full chapters before you get bored and think up something else.
Or maybe Keep the Russians as the 'antagonist' but instead of just power, they want to destroy what the European Union and America have become. But maybe thats just me. Russian's always seem to get the 'Villian' in stories. Atleast from what I have noticed. They can still be the antagonist, and your protagonist can be from America or where ever. But, go with what you want. Sounds like an interesting idea though.
I was thinking that the Russian government chiefs had no idea what was going on, since the project was being run by a group from the Department of Defence, and a couple of intelligence spymasters from the SVR. The Russian president and his chief staff would know nothing off the operation until it was actually underway, sometime near the end of the novel.
As Scoody said, it's all about the characters. However you do run the possibility of being a little too much like GoldenEye, evil russian general/spy/something uses EMP to something something something without government's knowledge. My advice is try and avoid the "Russian Iron Man" stereotype, it's overused and won't do justice to your characters.