Re: actually no
The way to detect imminent overload is the way everyone else does it. Half hour billing and let the market decide.
Businesses pay a different price for leccy every half hour. Producers earn that price.
Its only if the free market consistently fails or is horribly unfair that regulation is needed.
That may be the case, but no need to panic.
A massive fleet of personal mobile energy storage devices that can automatically choose _when_ they purchase, could be, overall, a very good thing for energy markets. In theory when you are working from home your car could even earn money by returning energy to the pool if prices are high enough.