THE SOLAR CENTURY

According to New Scientist, the world’s present 15 terawatt energy demand could be met by an area of 300,000 square kilometers (about the size of the UK) covered with 20% efficient solar photovoltaic (PV) cells. Environmental Graffiti suggests it is not impractical to think of carving such an area out of the Saudi Arabian, Australian or Saharan desert.

Solar thermal installations, also known as Concentrating Solar installations, use sunlight-reflecting parabolic mirrors to heat liquids that flow to plants where they boil water into steam to drive conventional generators. These systems are an even more efficient, less costly way to use desert sunlight. As recounted by Environmental Graffiti, there is probably an absolute limit to PV efficiency. Solar thermal plants may end up being the preferable way to generate commercial scale solar energy.

NewEnergyNews is interested in Environmental Graffiti's citation of research showing rooftop wind turbines and solar panels create more greenhouse gas emissions during manufacture than they prevent. No manufacturing process is likely to be emissions free. PV cells do require the handling of some troublesome materials. But more emissions than they prevent? If anybody out there has these numbers or knows of a website that has them, please check in.

Welcome to the Solar Century
January 4, 2008 (Environmental Graffiti via Environmental News Network)

WHO
Environmental Graffitti, a popular UK environmental blog; researchers in the solar energy field (University of Delaware, University of California)

click to enlarge

WHAT
Based on Solar power: The future's bright, Environmental Graffitti suggests that the transition to a solar energy-based society is imminent.

WHEN
- Just “a few years ago” solar photovoltaic cells were too expensive and inefficient to represent a formidable source of electricity.
- In 2003, Germany instituted a feed-in tariff requiring utilities to buy solar energy generated by photovoltaic (PV) system owners at twice the grid price. Germany now produces 3 megawatts of solar-generated electricity.
- In 2000, PV cells turned 5% of sunlight into electricity. In 2007, a new PV cell got to 40%.

It might seem like a lot of land but on a global scale it isn't. Oil fields probably take up just as much space. (click to enlarge)

WHERE
- Germany’s 600,000 PV cells are 60% of the world’s total.
- The 40% efficiency was accomplished by researchers at the University of Delaware.
- The world’s present energy demand is 15 terawatts.

WHY
- The scale of present solar energy industry activity is driving exciting new research acoomplishments. New manufacturing techniques led to the record-setting 40% efficient PV cell.
- Commercially available PV cells are about 20% efficient, moving solar energy cost/watt prices closer to natural gas and nuclear prices and bringing PV system pay-off periods down for the consumer.
- Stocks in solar energy industry companies, regarded as the fastest-growing in the world, are valued at $100 million.
- University of California researchers are trying to develop soluble materials PV so less efficient cells can be made in a much, much cheaper “printing” process.

Immense fields of photovoltaic cells are already a reality in the California desert. (click to enlarge)

QUOTES
Environmental Graffitti: “So why won’t it happen tomorrow? Well for a start, whilst a few western European nations are implementing the German model, most western governments are simply failing to support fledgling renewable energy companies. For example, last year the UK government decided to plough millions into extending the life of its nuclear and fossil infrastructure and provided limited help for energy startups, let alone potential consumers of renewable energy…There are also still a plethora of technical issues to overcome…how do we store the energy solar power creates for a rainy day?”