Trust in the smart grid to automatically reduce demand by 25% for a full week?
That's making an assumption of solar capacity far beyond the wildest dreams of those that wish to supply it. I'll assume it's a simple error instead of a deliberate attempt to mislead.
Tom Murphy is a physicist, not a journalist
However the person I referred to is not Tom Murphy is it? However on the topic of the blog you linked, an assumption halfway down the page was enough capacity to supply power for a week. That really show that while interesting anything derived from such an assumption is somewhat irrelevant to what we are discussing and cannot be used as an example of there not being enough storage one way or another - it just shows it can't be done for a week. Due to the nature of grids and distributed power generation it's the wrong approach anyway since there is no requirement to provide enough storage for a single second.
His further point was that it would be much simpler to reduce demand by travelling less, eating less meat, better insulating buildings, heating them less, etc.
Quite true, and that's starting to happen a bit as electricity utilities such as my former employer indulge in price gouging. However we'll still need new generating capacity as the operating generators are being shut down faster than that rate of decline simply due to it being too expensive to patch up old equipment beyond a certain point.
As for the Slashdot article, it was essentially content free: there's a thing called grid storage, batteries used for it have different requirements, some people are doing research on that topic. Is that news? Did anyone on Slashdot not know that already? Hard to get sucked in by a journalist that has nothing to say.
It is a solution to a problem that doesn't really exist that is worse than the status quo - so most definitely misleading. The research is into better ways of filling small gaps and unexpected outages just like pump storage has been doing for a few decades and it has been misrepresented as "grid storage". I've been told by a transmission engineer in his late 70's that distributing power used to be almost as difficult as that journalist and some others here seem to think - and then transistors started getting used in control systems.
He also wished there were a lot of solar panels around back in the day since they pump out nice clean sine waves at whatever timing you wish at the control room so can be used for power factor correction, plus they are spread around a lot and can be brought online or taken offline with ease. As a bonus the capital cost was paid for by someone other than the power utility.
Forcefully reduce demand through brownouts?
I thought you Americans got used to such things when you embraced deregulation and let Enron et all in the door? With a huge east-west grid and a lot of HVDC connections to make line loss almost irrelevant there is so much stuff pumping power into that grid that it should take a massive event for such a thing to happen in a widespread manner for any reason other than gross mismanagement. For a start there are so many gas turbines sitting on coal seam gas or similar just waiting for a chance to spin up for more than an hour or two every few days. There are baseline units of hundreds of Megawatts mothballed until the base demand increases again.