How far has solar technology advanced in recent years?

Since the introduction of the first practical solar cell in 1954, the efficiency of silicon-based solar cells has more than doubled — growing from 6% to an average of 15% in 2007.

(The Economist)

What about in terms of cost efficiency?

Since the introduction of the first practical solar cell in 1954, the efficiency of silicon-based solar cells has more than doubled — growing from 6% to an average of 15% in 2007. (The Economist)

Improvements in manufacturing have reduced the installed cost of silicon solar panels from about $200 per watt in the 1950s to $2.70 (as of 2004).

(The Economist)

But is solar a significant part of the world’s energy mix?

In 2006, solar-generated power accounted for less than 0.1% of the world's electricity supply.

(Wall Street Journal)

When will solar really take off?

Experts agree that the “tipping point” for solar power will arrive when the capital cost of solar power falls below $1 per watt — roughly the cost of carbon power.

(Daily Telegraph)

What is one measure of solar’s potential?

Just 20 days of sunshine produces the same amount of energy as everything stored in the earth's reserves of oil, coal and natural gas.

(Union of Concerned Scientists)

How did solar get its start?

The photoelectric effect was discovered in 1839, when Alexandre Becquerel, a French physicist, observed that light could generate an electric current between two metal electrodes immersed in a conductive liquid.

(The Economist)

Which countries have emerged as leaders in solar power generation?

Germany led the world in solar energy production per person in 2005, with total installed photovoltaic capacity of 17.32 watts per capita. Japan was second with 11.13 watts per person — followed by Switzerland (3.66), the Netherlands (3.12), Australia (2.97) and Austria (2.93)

(International Herald Tribune)

Anyone else?

Improvements in manufacturing have reduced the installed cost of silicon solar panels from about $200 per watt in the 1950s to $2.70 (as of 2004). (The Economist)

China claims an estimated 30 million solar households — or nearly 60% of the solar capacity installed in the world.

(Worldwatch Institute)

How did this come about?

In China, solar energy is used to provide hot water for showers and washing dishes — a process known as solar thermal.

(Worldwatch Institute)

Which country stands out as a rising star in the solar energy field?

In May 2007, South Korea began development of the largest solar power plant in the world. The $170 million plant includes 109,000 solar modules, covering the size of 80 football fields.

(International Herald Tribune)

How does the United States stack up?

About one-thirtieth of 1% of all the electricity produced in the United States is generated by solar power.

(Wall Street Journal)

Is there money to be made in the solar market?

The market for solar power grew by about 40% a year between 2000 and 2005, reaching about $11 billion.

(The Economist)

In 2006, solar-generated power accounted for less than 0.1% of the world's electricity supply. (Wall Street Journal)

And which country’s solar industry is growing particularly quickly?

In 2006, China passed the United States to become the world's third-largest producer of solar cells — trailing only Germany and Japan.

(Worldwatch Institute)

What hurdles does the industry face in its drive to expand?

The expansion of the solar energy industry is currently suffering from a chronic shortage of silicon — the basic material used to convert the sun's rays into electricity. Since 2004, prices have risen 50%.

(Financial Times)

Where is silicon found?

Silicon covers 21% of the earth's crust, essentially ensuring a limitless supply.

(Atlantic Times)

So what is the problem?

Only now are refining capacities being built up from the 30,000 tons the solar power industry currently shares with the semiconductor industry to a new level of 80,000 tons.

(Atlantic Times)

When is the shortage expected to ease?

The worldwide shortage of poly-crystalline silicon is not expected to ease in 2008 — and could continue for at least another five years.

(Financial Times)

How large is the solar industry’s appetite for the material?

In 2006, for the first time, more than half of the world’s polysilicon was used to produce solar cells.

(Worldwatch Institute)

Is there an alternative to silicon-based systems?

The expansion of the solar energy industry is currently suffering from a chronic shortage of silicon — the basic material used to convert the sun's rays into electricity. Since 2004, prices have risen 50%. (Financial Times)

While silicon-based solar cells currently represent 92% of the photovoltaics market, some producers are seeking to develop new solar materials — including a conductive polymer salted with nano-size carbon molecules called buckyballs.

(Business Week)

Have the world’s largest energy companies embraced solar?

Despite its new sunburst logo and "Beyond Petroleum" slogan, BP still invests $12 billion, or 25 times more, on oil and gas activities than on its wind and solar division (as of 2005).

(New York Times)

Why does solar seem tailor-made to meet the world’s energy needs?

Solar power supplies rise and fall with the daily demand pattern of energy consumption. In mid-day, when most appliances are running, the most solar power is available, and then tapers off toward the evening. It is thus always a peak supplier.

(Atlantic Times)

And finally, how is solar technology being deployed in the developing world?

Solar-powered flashlights help Sudanese refugees to scare away thieves, make nighttime journeys — and light school desks for children and adults to study after the day’s work.

(New York Times)