Are tax credits basically the same thing as subsidies?
They can be considered so - it's a common way to subsidize something without spending money on it directly. Still, it depends on who you ask. They encourage spending on something that might otherwise not be made - but there has to be enough of a market for it that the consumer finds it valuable in itself, since the tax credit usually doesn't cover the entire cost.
The clean energy tax credits produce a modest amount of demand for clean energy. The effect of price increasing from greater demand is going to be balanced out to some extent by the greater economies of scale that reduce production cost. Combined with some of the grants in the Go Green Fund it may have an effect on raising prices, but nowhere approaching what has happened in Germany. The major difference here is that there is an investment in a variety of clean energy (at least, that's the plan), and not a huge amount given to a single technology.