Solar photovoltaic systems generate electricity using technologies that capture the energy in sunlight. Many parts of the United States—especially the Southwest—have abundant solar resources (see Figure 5, which shows estimates of the average daily total radiation for flat plate solar collectors). Before investing, however, firms should commission a thorough professional study of a specific site’s solar resources. Even if it reveals lower or moderate resources, solar power could still be financially attractive, depending on financial incentives and regulatory context.

COAL
The top 25 GHG emitting countries collectively account for approximately 92 percent of global coal consumption (BP, 2009). Coal mining and use is highly concentrated. Five countries account for nearly three-quarters of worldwide consumption. Unlike oil and to some extent natural gas, most coal is consumed domestically.

OIL

Emissions intensity is a composite indicator of two other major factors contributing to a country’s emissions profile: energy intensity and fuel mix.

Today, each Chinese citizen produces only one-fifth the GHG emissions of an average American consumer, and China still has many unmet energy needs. Most Chinese have a much lower standard of living than the average American. Half the Chinese population has no access to winter heating, and most have limited access to motorized transportation. Therefore, the challenge for China in the short term is to reduce the rate of growth of its GHG emissions as it strives to meet the growing energy demands of its people.