The number of humans on Earth has now passed seven billion. And world energy usage is estimated to inflate more than 25% during the next 15 years, and probably will nearly double by the year 2050. But how much energy we need to exploit, and how we extract it, relies upon the decisions we make now. And those energy decisions have effects on Earth's climate. We already see the possibilities of the 21st century renewable energy. But, today, most of the big and powerful nations still heavily depend on 19th century technologies.
Some creative strategies demonstrate that wind can supply entire communities with power. And control, conservation and effectiveness can cut projected world energy requirements 30% by 2030. But how to achieve that on a massive scale? That's not just a scientific issue, but relies upon political, economic, cultural, national, and security decisions made by real people living in the real world.
Geologist Richard Alley is one of the many climate authorities who accepts the fact that the ongoing human energy models on Earth are warming the planet. But he also believes that the answers are out there... in the wind, in the sun, and in the heads of the scientists, discoverers, designers, architects and engineers.
Planet Earth is flooded with inexhaustible energy. The oceans conserve heat and produce wave and tidal power. Plants harvest sunlight and accumulate its energy in various forms. The Sun heats the atmosphere and therefore generates wind which we can exploit. But the largest and most hopeful energy source is the Sun itself.
Sunlight bathing the Earth's crust offers about 120,000 terawatts. If the Sun's energy were disseminated evenly around the world, it would average around 240 watts per square meter. Frank Shuman was the first scientist who, around 1910, invented machinery that could focus sunlight on metal tubes, heat liquid, and run a steam turbine. The steam drove a 75 horsepower engine that pumped water from a river to irrigate the soil.