[Straw]

If you want heat, why bother converting sunlight to electricity first? You lose 80%. Is it that much more expensive to use mirrors to concentrate sunlight and capture near-100% of the energy as heat?

[ted_dunning]

Because with a heliostat you have to move the energy as heat and that isn't as efficient and definitely not as easy or cheap as moving it as electricity.

Do the numbers. Making the top of the heliostat isn't what matters. What matters is making the inside of a pile of dirt that hot.

[Straw]

They are pitching co-located PV, and they already have a system to move the heat inside the pile of dirt!

[turtlebits]

Mirrors require heliostats.

PV panels are dirt cheap and dead simple. They're also portable. Wire a bunch of panels to a heating element and dunk it in sand/water/etc.

[pfdietz]

And PV panels work with diffused sunlight; high concentration solar only works with direct sunlight.

[apexalpha]

If you 'bother' with converting it to electricity first you can sell the electricity for profit and only convert the excess to heat.

[kragen]

I don't understand how, but apparently solar photovoltaic panels are indeed cheaper than thermal solar collectors now.