Save for later Print Download Share LinkedIn Twitter While every energy scenario assumes thousands of gigawatts of new renewable capacity will be built in the next two to three decades, critics argue this is not feasible. They mostly point to intermittency and growth sustainability issues. Wind and sunlight are intermittent, they emphasize, which puts the grid -- and consumers' safety and finances -- at risk when the wind is not blowing and the sun not shining. They also insist that projected renewable growth is so fast that it won't be possible to find enough money to fund projects, or enough raw materials and even space to build them (see graph). So, objectively speaking, are the critics right? Some of the arguments have more truth and backing behind them than others.