Renewable energy sources

This city’s power supply comes from a coal power plant. But the citizens are unhappy. The coal power plant releases gases: carbon dioxide, which adds to global warming; and sulphur oxides and nitrogen oxides, which pollute the air. Another problem is that coal power production is a one way process. It’s a non-renewable energy source.

At some point in the future all the coal will be used up. People want alternative energy sources that will not run out. The city has high levels of sunlight, so they decided to convert the sun’s energy into electrical energy. The most common way of doing this is to use solar panels. These consist of materials that absorb energy from the sunlight.

Sunlight frees electrons inside the panel, resulting in a flow of electrical charges. But you need many solar panels to supply the entire city with energy. And when the amount of sunshine is low, the solar power plant generates less electricity. Despite the size of the solar power plant, it does not produce as much power as a coal power plant, even when there’s lots of sunlight. So, the city decided on another energy source too.

THE WIND Windmills have long been a simple way to capture moving energy, or kinetic energy, from the wind. Using this principle, engineers built a new kind of windmill, that could convert that kinetic energy into electrical energy: a wind turbine. The city built a collection of wind turbines, which together make a wind farm. The wind spins the blades of the turbines, which power a generator, which produces electrical current. But wind farms also have a disadvantage: when the air stops moving, so do the turbines.

Luckily, this city gets pretty windy. However, the coal power plant still produces more power than the wind and solar power plants combined. There is one more energy source that the city can use: strong waves. Waves are moving water. This movement means kinetic energy.

One way to capture this energy is to use a large chamber. When the waves press into the chamber, the air pressure inside increases, forcing air out. When the water level drops again, the air pressure inside drops too. Air is sucked back into the chamber. The moving air spins a turbine, which is connected to a generator.

And we get electricity from the waves. This kind of wave energy power plant is called an oscillating water column. As with solar and wind power, the power production slows down when the waves calm down. Generating electricity from coal is a one way process. The solar, wind, and wave energy plants work differently.

Sunlight, wind, and waves replenish naturally. They are renewable. But there are disadvantages. They are more expensive to construct than coal power plants. And coal has a higher capacity for generating power.

Solar and wind power do not generate as much power as coal. And the technology for building wave power plants on a large scale is still in development. At least, renewable sources don’t release any harmful gases. However they do impact the environment.. Wind turbines and wave power plants are extremely noisy.

And solar power plants occupy large areas, sometimes destroying natural habitats. Renewable energy sources are unlimited and do not release harmful gases. On the other hand, they have a lower capacity than non-renewable energy sources, and cost more to build. Solar, wind and wave energy plants rely on weather patterns to reach their maximum power capacity. But the more we use renewables, the more we learn about how to harness their energy efficiently.

And this city is moving to cleaner energy sources, that also will not run out.