As I said yesterday, it's not easy to summarize the "benefit" issue in the Canada - Renewable Energy panel report. But just quickly, the dissenter puts the two sides succinctly. The majority view (as desribed by the dissenter):
9.1 ... In essence, the Panel majority has found that the circumstances of ensuring a reliable supply of electricity that achieves certain objectives sought by the Government of Ontario justifies the rejection of the competitive wholesale electricity market as the relevant focus of the benefit analysis. The Panel majority has furthermore suggested that, in these circumstances, the existence of benefit could be determined by focusing upon the rate of return associated with the FIT and microFIT Contracts and comparing this with the average cost of capital in Canada for projects having a comparable risk profile.
Basically, electricity markets are so distorted that you can't examine benefit using those markets alone -- you have to look to other markets (but there wasn't enough evidence here to reach a conclusion).
The dissent view:
9.23 ... by contracting to purchase electricity produced from solar PV and windpower technologies under the FIT Programme at a price intended to provide for a reasonable return on the investment associated with a "typical" project, the Government of Ontario ensures that qualifying generators are remunerated at a level that allows them to recoup the entirety of their "very high" capital costs. As the complainants argue and Canada accepts, such levels of remuneration would never be achieved through the unconstrained forces of supply and demand in a competitive wholesale electricity market in Ontario. Nor could they be achieved within the constrained forces of supply and demand which actually do operate within the wholesale electricity market in Ontario, without an intervention which remunerates the facilities which generate power from solar PV and windpower technologies at a higher rate than is paid in respect of electricity generated by the other technologies663. It follows that by bringing these high cost and less efficient electricity producers into the wholesale electricity market, when they would otherwise not be present, the Government of Ontario's purchases of electricity from solar PV and windpower generators under the FIT Programme clearly confer a benefit upon the relevant FIT generators, within the meaning of Article 1.1(b) of the SCM Agreement.
Basically, buying energy from wind and solar producers at prices they could not have otherwise obtained in the market confers a benefit. End of story.
That leaves out a lot of nuance, of course, but it's a little taste of the issue.