To be fair, the article doesn't say that 90% of homes in Europe are powered by renewable energy. It says that almost 90% of new power added to energy grids in Europe came from renewable sources last year. Also keep in mind that the data is from a renewable energy advocacy group. That is an important distinction, though it still shows that renewable energy is big in Europe.
Here in the US, I'd wager that the biggest factor in renewable energy not taking off has more to do with corporate lobbyists getting the right legislators in their pockets than it not being 'cost effective'. Local ordinances won't allow me to install solar tiles on the roof of my home, for instance.
News 
Market Data 
Discover 
