Yes. I always say myself that solar is always integrated with another technology. If you try to size solar to supply 100% of demand, you're probably over-sizing and you have too much investment for nothing. The best, again, is an energy mix. It could be supplied with extra fossil fuel or a gas-fired system--it's always the case, anyway. You always have to look at doing the first job with solar. It really is where it counts the most.
So if you can preheat your water or your air with solar, that's the way it works best and that's where you have the lowest cost per kilowatt hour. Don't try to have 100% of the system work with solar, because for example, in summer you have overcapacity. That's where Okotoks, for example, is a good example of storage over a longer period.
However, I must say, they've tried district heating like that in many places in Europe, and the industry has not caught on because of the non-financial issues. It's not really an industry that works that much. I wouldn't say there is such an industry in countries like Austria and Germany of district heating; it's more localized, decentralized heating systems that you see.