For the past eight years, Chevron has promoted "profitable renewable energy" as a core component of its business plan. Yet Chevron recently has retreated from key efforts to produce clean energy. This includes the renewable power group, which invested in or built utility-scale solar and geothermal projects with margins of 15% to 20% or more, according to a dozen people who worked on the projects. Chevron earlier this year sold the 48-person business unit that builds small solar and landfill-gas systems and energy-saving retrofits for federal agencies such as the US Department of Defense. A pullback from renewables doesn't surprise some analysts, who say returns of even 20% can be bested by oil and gas projects that can generate profits of 25% to 35%. While climate change is drawing public attention, oil companies have had mixed success promoting their green energy efforts.