[cinquemb]

There's also CSP[0] which has taken off recently in the past 5 years (fastest growing[1] segment at ~4GW total vs ~177GW for PV) which is overshadowed by most compared to PV mind-share, but is better suited for projects that require more energy/load requirements.

I also can see CSP being more attractive to locales with existing grids and who can probably attract financing easier for a +100 MW plant to one institution vs 100k+ people having to be sold on such to install PV on their house/property. There's definitely a market for both and they will all chip away at fossil fuels rapidly coming from different sides of the market for energy.

[0]: https://en.wikipedia.org/wiki/Concentrated_solar_power

[1]: http://www.examiner.com/article/market-growth-for-pv-solar-v...

[PhantomGremlin]

The problem with CSP compared to PV is all the moving parts. You need something like molten salts, coupled with a conventional turbine and generator. PV can be purely solid state, a thing of beauty IMO compared to mechanical "contraptions".

[cinquemb]

That's less of a problem, and more of a feature, because those molten salts enable CSP to provide more power for up to 16 hours[0] sans sunlight which is important if you need dispatchability, which is not really comparable to PV's which cannot offer the same now, hence why CSP is not killed off by PV's and has continued to grow along with PV's.

You also have to consider that people who live in apartments or rent a house in developed markets are pretty much either locked out of the market for PV's or not incentivized to pay out of pocket (even considering the subsidies/financing that exist [looking at you Solar City]) for such systems. I'd say that share of the population is far larger than people with a mortgage/own a home and are interested in such systems.

This embodies the situation: "Does this mean CSP will eventually disappear, trampled by PV? Not necessarily. CSP has one major advantage over PV: dispatchability. Current CSP plants can store thermal energy for up to 16 hours, which means that their production profile can match the demand profile (just like a conventional power plant). PV is not dispatchable, as a feasible commercial energy storage system does not yet exist. Dispatchability will be increasingly important when and where renewable energies achieve high penetration rates, so two things can happen: CSP becomes a commercially viable solution before a commercial PV storage system is developed, carving its own market segment; or the PV industry quickly solves the storage issue and becomes the solar technology of choice."[0]

[0]: http://thisisxy.com/blog/cannibalization-in-renewable-energi...

[PhantomGremlin]

I agree with you, in theory.

Practically speaking there hasn't been a lot of large scale CSP done, and e.g. Ivanpah[1] has a lot of limitations and teething problems. It has no energy storage, and it needs to use natural gas for 4.5 hours each day during startup.

As for your assertion that CSP has continued to grow, the one data point I linked to claims "little appetite" from California utilities for power from plants like that.

One thing can probably both agree on is that CSP is a "go big or go home" technology. It's not suited for small scale deployments. Which makes it quite complementary to rooftop PV.

[1] http://breakingenergy.com/2014/10/29/at-ivanpah-solar-power-...

[cinquemb]

> "Practically speaking there hasn't been a lot of large scale CSP done…"

Maybe not in the United States, but it has taken off in Spain (looking at Wikipedia I cited earlier, which is probably better suited to take advantage of it in theory since installations are near population centers). I see far more interest oversees than in the United States… which is not surprising considering all the entrenched players that simply don't have the influence to the same degree in other places.

I can agree with this statement to some degree: "It's not suited for small scale deployments. Which makes it quite complementary to rooftop PV.", but seeing how it's serving a need that PV has not been able to provide to date despite it all, I'd hardly say its "go big or go home", there's far more abundant sodium and potassium available in the earth's crust vs lithium.