Just wanted to tell you one "gotchya" in building GW.
You can create a horrible problem if you go to another connected city and click "build" after you've already started building from a different city. It's all about the regional synch. I usually use one city to build the GW just to avoid the issue. If you go to another city during construction or after it's built, don't panic if you don't see the GW from there. Give it some time. Eventually, you'll get notice that the GW has started and it will run through all the steps of building and you will be asked to do the ribbon cutting in the new city.
Whatever you do, do NOT confuse the server by clicking the build button in the other cities. If you do, when the game finally catches up, it will completely hose your entire region; there is no fix. So, safest way is to build the GW from one city, wait until it's completely finished and you've had the ribbon cutting ceremony, then load each of the other connected cities and wait for it recognize the GW. Go through the ribbon cutting ceremony on each, and you'll have all that solar power streaming to each of those cities.