Seems like just about everyone missed the political and economic ramifications of getting rid of their plants, so I'll throw my two cents in the ring.
To start off, 10 years isn't enough time for Germany to replace nuclear energy with renewable energy. About a third of Germany's energy comes from nuclear power, and it costs less than a third of wind power and less than one-twentieth of solar power. What does this mean? As far as this decade is concerned, replacing nuclear energy with renewable energy isn't economically feasible, so they'll have to look elsewhere for their energy needs. Elsewhere, of course, being surrounding nations.
The way I see it, you have a few players about to try to sink their claws into Germany. First, you have France, which is always desperately trying to lash itself to Germany to prevent them from being a threat ever again. How do they go about doing this? They make themselves as essential to German plans as possible. France is about as pro-nuclear as a nation gets, so I don't doubt they'll start building extra reactors in order to export as much energy as they can to fill in the gap Germany hamfistedly created. They've already been doing this to a degree, but you can expect them to ramp up their efforts.
After France, you have Russia. Russia has been trying to secure a cement a relationship with Germany for forever and a day now, and this could finally be their ticket. Why? Such a relationship would serve to solve many of Russia's economic, military and demographic problems. Also, the two nations would essentially neutralize all of Europe, leaving Russia to do basically whatever the hell it wanted as there'd really be no one to enforce "anti-Russian" policies (which sounds worse than it actually is as these types of policies tend to benefit both America and Europe). At the very least, we prefer Germany to remain neutral when it comes to Russia. But since we're focused and involved in the Islamic world, we can't really do much in that theatre other than politely ask our friends for a favor.
In any case, Russia. So they have the Nord Stream pipeline which bypasses all the transit states between Russia and Germany, and is scheduled to go online in 2012 (currently in the process of final testing). It should produce 55 cubic meters of natural gas per year. That's enough to replace half of the electricity produced by nuclear power in Germany. All Germany would have to do is build a few natural gas-burning power plants, and they'd be good to go.
Finally, we have the dark horse. Mother****ing Poland. Poland is pretty much outclassed in every possible way by the other two nations, but they have a trump card. See, they refuse to get with the times. Most of their energy demands are met by coal. Coal is cheap. Dirt cheap. Were Germany to choose coal to replace that energy gap, they'd need only to construct a few coal plants, which can go up in a year or two and coast pennies next to nuclear power plants which cost several billion euros and can take anywhere from 5 years to a decade to construct. It's dirty, and its politicaly incorrect, but its there.
So you have France who needs to make itself important to Germany so that they'll never attack again, you have Russia who wants to make Germany its partner so it can have free reign to do as it wishes, and you have Poland stuck in the middle between a resurgent Germany and a resurgent Russia, and the overwhelming feeling that they're going to get raped any day now. France has a politically attractive plan that is economically expensive, you have the Russians who already have the fuel source ready for the picking, but would require making a deal with the devil, and you have Poland which has a politically unattractive plan that is economically dirt cheap. Also, the German plan, which is stupid. All have long-term consequences, so it'll be interesting to see which Germany goes with.