So how are developers supposed to hit this target? Rob, do you want to take that one?

Yeah, so this is, we already know that to meet the other emissions part of Part L, you're only going to deliver it with a heat pump.

Strictly speaking, you could use other forms of heating, but the amount that, because the notional building uses a heat pump, you pretty much force down the heat pump route.

What we're talking about here is what is generated on site in addition to what your heat source is.

So the way they've calculated this, they want PV to be included to every dwelling on the site.

It's not like a site-wide calculation.

And that's 40% of the dwelling's ground floor area.

We have quite narrow options in terms of you moving away from this requirement.