Joan - You are about to get one of my rants! A MLP pays out all of its free cash as distributions - correct? Thus how does it pay for building new projects and buying things like SUN? Am sure you know the answer - they issue debt and equity at about a 50/50 ratio. No other way since unlike the US Govt a MLP cannot simply print money.
It also is NOT dilution or dilutive if the assets purchased provide a cash flow that is greater than the distribution on the new units. ETP issued about $2B in units to pay for SUN. Those units require about $180M a year. Don't you think that SUN will pay ETP more than the $180M even after they pay about $80M in interest?
The at the market sale of equity is a way to reduce costs of issuing and reduce market distrption. That means we do not see the price go down $2 or $3 when a block is dumped on the market, instead units are sold when there is strong demand "at the market". Better for exisiting unitholders as ETP will get a better price and reduce costs.
Adding equity during an expansionary phase isn't necessarily a bad idea. Creditors require reasonable equity or skin in the game. A solid equity position is the framework for continued funding and as a shareholder of both ETE and ETP, i'm on board.