But batteries for grid storage will have to be very cheap to compete with fossil fuels as an on - demand energy source. (newscientist.com)
We simply don't know how long it will take to develop a form of grid storage that is scalable to what we need. (theness.com)
But while they are great for electric sports cars, the batteries aren't cheap and aren't flexible enough to cope with wildly different loads for power grid storage. (newscientist.com)