Those are often interconnected with diesel systems, so there is some very sophisticated switching that goes on between them. It depends on the scenario, really. If you are talking about a house or a cabin in the woods, you are going to need a diesel generator and some batteries. But in terms of large-scale commercial applications of batteries within a large transmission system—not a remote system, but ones we have in the bulk of North America—we don't need battery storage at the present time. But we certainly need to start thinking about it if we want to get to those levels of penetration of renewables that will receive 30%, 40%, 50%, 60%, or 70%. There's a lot of innovation going on right now as utilities prepare for that time when they will need it.
Storage can take on many different aspects. Batteries are one, and there are a lot of different chemicals. I'm not an expert in storage to that level of granularity. But there are other options out there. There are flywheels. There's compressed air. There's pumped hydro, and so on. Jurisdictions in Quebec that enjoy significant amounts of stored water have storage already as an inherent part of their system.
I would say that utilities in Ontario are starting to look at these areas of innovation and research as preparation for such time as they will need storage.