Cleaner clean fuel sources

I came upon this in an article about alternative clean power sources:

“If 1 percent of the earth’s hot deserts produced clean solar-thermal energy, they would meet the entire planet’s current electricity demand.”

Solar-thermal energy in this case involves using hundreds of large ground-level mirrors to concentrate light on a tall tower, which then converts the light into heat, and then into electricity via a steam turbine. Such a source of power would require massive amounts of space and decent electricity infrastructure already in place to take it from a [presumably] desert area to villages and cities. While making mirrors and one steam turbine would definitely require fewer minerals (like gallium, arsenic, cadmium, and tellurium used in PVs) than photovoltaic-based solar power, and solar-thermal energy would probably have more attainable economies of scale, I wonder how transferable solar-thermal energy will be in reality, compared to PV solar. Given the lower marginal costs and seeming efficiency (at least, based on that quote), it seems strange that solar-thermal hasn’t become more widespread.

The writer, David Benjamin, argues that the visibility [or lack thereof] of these cleaner technologies is why they’re not more widespread–but one look at the controversies behind large-scale wind farms and PV farms seems to hint at a different relationship with renewables.

In a preliminary talk with a vertical wind-turbine developer, the start-up’s co-founder claimed that their product’s biggest selling point was its visibility and therefore image- and public-relations-boosting abilities. Should this really be the driver for innovation of clean tech — aesthetics, instead of efficiency? Is the public still so unconvinced by our rising gas prices, multiple wars in oil-rich countries, oil tanker crashes, climate change, and domestic ethanol biofuel subsidies (which were supported initially because the ethanol blended well with gasoline as a replacement for more toxic additives), that we need to focus on increasing the visibility of renewables for them to be used?

Link to article : http://www.nyfa.org/nyfa_current_detail.asp?id=272&fid=1&sid=17&curid=705