I believe an overall carbon cap is far superior to prescriptive standards. A cap makes no prejudgment as to which technology is best; it says to industry 'you figure it out' just setting how much carbon is allowed in total. In other words it doesn't pick winners in advance.

The first big advantage is that it should prevent leakages across carbon boundaries. For example substitution of coal for gas which we are seeing in WA electrical generation and soon apparently in ammonia production. A prescriptive standard could say for example if you use coal your emissions must be less than the gas equivalent, and then we'll cut it year by year. Why not make the standard the solar powered equivalent?

The second big advantage is avoiding moral lapse. Obviously corporate sleazoids will put a huge effort into making their own standards as lax as possible. Instead of swapping carbon permits behind the scenes they will set up permanent lobbying in Canberra for papal dispensations. A good example is the corporate average fleet economy (CAFE) in the US. Car manufacturers got the weak standard they wanted and now they are going broke. Stick with the auctioned carbon cap that covers everything and avoids loopholes. Then give back the auction revenue which can't be spent on more carbon as the limit has been set.

Changing tack I've seen a WW2 aviator's watch painted with the radium from the Hunter's Hill site. The hands and numerals glowed lime green in the dark so could be read in a darkened cockpit. Never heard of any associated health problems.