Utility-scale solar is probably the only way to achieve real scale and reduce carbon emissions, according to Sun Microsystems co-founder-turned-venture-capitalist Vinod Khosla.

In a report filed by Los Angeles Times, Khosla has mentioned that size matters.

Costing about 18 cents a kilowatt-hour at present, solar thermal power is roughly 40 percent cheaper than that generated by the silicon-based panels that sit on the roofs of homes and businesses and analysts say improved technology and economies of scale should help lower the cost of solar thermal to about 5 cents a kilowatt-hour by 2025. That would put it on par with coal, the cheap but carbon-spewing fuel that generates about half the nation's electricity, added the same report.

At the same, it is being said that solar plants require staggering amounts of land, which could threaten fragile ecosystems. And in contrast to rooftop panels, which enable homeowners to pursue energy independence, "these centralised facilities keep consumers tethered to utility companies".