(Music)
No matter how we choose to live our lives, we’re going to need more energy in the future.
The problem is that all the energy sources have their limitations and environmental impacts.
There are problems and benefits with them all. Let’s have a look.
(Music)
Coal is fossilized land plants that have been buried deep in the earth for millions of years.
The pressure and the intense heat at those depths have turned vegetation into a hard
black material that is primarily carbon. Around 40% of the world’s electricity is
based on coal. Incredibly, around 5% of all energy used in the United States is simply
to transport coal so it can be burned as a fuel.
(Music)
And then there’s something we all pay a lot for, especially here in Europe, and that’s
oil. Primarily used for transportation, but a small percentage of it is also used to generate
electricity. Just like coal, it comes from organic material, fossilized eons ago. Worldwide,
it makes up about a third of the energy supply.
(Music)
Natural gas is also abundant, but unlike coal
and oil, it’s virtually clean, and it is comparatively cheap and easy to build a gas-fired
power station. 20% of the world’s energy supply comes from
gas, and it has grown rapidly to 27% of the total energy used here in the United States,
and 30% of the electricity.
(Music)
Nuclear energy is the energy from the nucleus,
the core, of the atom. In a nuclear reactor, atoms are split to release that energy. Nuclear
supplies 5% of the world’s energy, and 14% of its electricity.
Here in Sweden, it provides around 40% of the electricity; in France it’s more than
70%. Nuclear power is one of few large-scale alternatives to fossil fuels.
(Music)
Hydropower has many benefits. It is clean; it doesn’t produce greenhouse gases or add
pollutants to rivers and streams. It’s fairly cheap, and since we can turn the turbines
on and off in minutes, it’s online whenever we need it.
And large dams generate almost a fifth of the world’s electrical power. About 17%
of all American rivers have dams that generate electricity. In total, there are some 2,400
dams in the United States. In China, there is ten times that number.
Perhaps the biggest problem is that in developed nations, almost all the suitable sites for
large hydro-electrical dams are already in use. So it’s difficult to see how we can
expand it much further.
(Music)
In my own country, Sweden, we have seen a
revival of what might be called mankind's first energy source: burning wood, or rather,
using biomass. Around the world almost 10% of the energy supply comes from using biomass
or waste. When we grow our fuel from wood, corn or algae,
or burn waste- that’s called “Biomass.” In my hometown of Malmo, biomass produces
40% of the city’s heat.
(Music)
It’s difficult to think of a cleaner way
of generating power than harnessing the wind. But currently wind supplies no more than 1%
of energy globally, and less than 4% of the electricity. Some countries have gone much
further. Turbines like these here in Denmark supply the country with almost a third of
its electricity needs. The biggest drawback is that wind is intermittent.
The wind doesn’t blow all the time, and everybody knows that the wind must be strong
enough for the generators to function at full capacity. Many people also object to how wind
turbines affect the beauty of the landscape.
(Music)
Every hour of every day, the sun beams more
than enough energy onto our planet to satisfy global electricity demands for an entire year.
On the plus side, solar energy is clean and abundant; you can do it small scale, from
a few watts to recharge a cell phone to large scale, hundreds of megawatts for industrial
generation and you can do it in remote locations, far from the grid.
But it does have negatives. It doesn’t work when the sun doesn’t shine, and even though
costs are dropping, it’s still expensive to install.
Maybe we can develop space-based solar power, where the sun always shines. Or expand the
use of solar mirrors in the high deserts of the world. We might design a safe nuclear
plant that runs on the radioactive waste we already have.
Maybe, in the future we will get our fuel from algae. Someone might come up with a cheap
way of taking carbon dioxide out of the burning of fossil fuels; we might even be able to
take it out of the atmosphere. What we do know is that tens of thousands
of scientists and entrepreneurs are right now hard at work, trying to develop brand
new energy sources and perfect amazing technologies, because they think they have the key to the
future. Maybe one of them does… or maybe it’s
someone we haven’t heard of yet. The developing world thirsts for energy and there's little
question that, in time, they will get it. And when they do, the brain power and entrepreneurial
spirit of millions will surely be unleashed, because a child today can have access to the
sum of mankind’s knowledge, and can add her own ingenuity to it, perhaps bringing
power to all the people.
Children: Seventy-five thousand...
(Music)