Disadvantages of renewable energy resources

Benefits of Renewable Energy

• Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution.
• Diversifying energy supply and reducing dependence on imported fuels.
• Creating economic development and jobs in manufacturing, installation, and more.

The most popular renewable energy sources currently are:

• Solar energy.
• Wind energy.
• Hydro energy.
• Tidal energy.
• Geothermal energy.
• Biomass energy.

The ocean can produce two types of energy: thermal energy from the sun’s heat, and mechanical energy from the tides and waves. The sun’s heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy.

Ocean thermal energy, osmotic energy, marine currents and some types of wave energy could produce base load power, electricity that is consistent and reliable. The areas with the most wave energy potential are the Pacific Northwest and Alaska in the United States, and the U.K. and Scotland.

Kinetic energy, the energy of motion, in waves is tremendous. An average 4-foot, 10-second wave striking a coast puts out more than 35,000 horsepower per mile of coast.

Waves are created by energy passing through water, causing it to move in a circular motion. Wind-driven waves, or surface waves, are created by the friction between wind and surface water. As wind blows across the surface of the ocean or a lake, the continual disturbance creates a wave crest.

The size of a wave depends on three factors: the distance over which the wind blows across open water (the fetch), the strength of the wind, and the duration that the wind blows. The larger these factors, the larger are the waves.

So in a nut shell, wave energy comes from the Sun’s heat energy which gets converted to wind energy because the atmosphere expands and contracts as the Earth spins on its axis.

When wind blows across the surface of the water, this creates friction between the air and the water causing a wave to form (NOAA). As the wave forms, it becomes easier for the wind to grip the water, creating larger waves. The size of the wave can depend on three things: wind strength, wind duration, and fetch.

To summarise, waves carry energy. The amount of energy they carry is related to their frequency and their amplitude. The higher the frequency, the more energy, and the higher the amplitude, the more energy. You can make these patterns yourself with the activity Investigating waves and energy.

Amount of wave energy can be determined by wave steepness and wave period. Wave steepness (gradient) = wave height / wave length. High energy waves have steeper waves and low wave periods. The greater the wind speed, the greater the wave height, the greater the wave energy.

Waves are a very important and necessary part of the workings of our planet; the motions they create perform a vital role in transporting energy around the globe and shaping the coastlines.

There are three main factors that affect wave formation: wind velocity, fetch, and duration.

One way to categorize waves is on the basis of the direction of movement of the individual particles of the medium relative to the direction that the waves travel. Categorizing waves on this basis leads to three notable categories: transverse waves, longitudinal waves, and surface waves.

A number of factors affect the size of waves. These include wind speed, duration, water depth, distance of wind travel over open water or fetch, direction of tide, speed of tide, etc. Higher wind speeds result in bigger waves and smaller speeds result in relatively smaller waves.

The largest waves occur where there are big expanses of open water that wind can affect. Places famous for big waves include Waimea Bay in Hawaii, Jaws in Maui, Mavericks in California, Mullaghmore Head in Ireland, and Teahupoo in Tahiti.

Most tsunamis are less than 10 feet high when they hit land, but they can reach more than 100 feet high. When a tsunami comes ashore, areas less than 25 feet above sea level and within a mile of the sea will be in the greatest danger. However, tsunamis can surge up to 10 miles inland.

In fact, the largest tsunami wave ever recorded broke on a cool July night in 1958 and only claimed five lives. A 1,720 foot tsunami towered over Lituya Bay, a quiet fjord in Alaska, after an earthquake rumbled 13 miles away.

100 feet high

You can’t surf a tsunami because it doesn’t have a face. Many people have the misconception that a tsunami wave will resemble the 25-foot waves at Jaws, Waimea or Maverick’s, but this is incorrect: those waves look nothing like a tsunami. On a tsunami, there’s no face, so there’s nothing for a surfboard to grip.

Although there is no concrete data on the exact number of people who have died while surfing, the number is estimated to be no more than 10 per year- which in a world of approximately 23 million surfers, is startlingly low. Among this unlucky bunch, there are several main causes of death.

several hundred meters

No. Because of their long wavelength, tsunamis act as shallow water waves. So no matter how far down you dive, you’ll still be caught in approximately* the same wave-induced current that will sweep you into deadly collisions with structures, debris, etc.

10 worst tsunamis in history

• Sumatra, Indonesia – 26 December 2004.
• North Pacific Coast, Japan – 11 March 2011.
• Lisbon, Portugal – 1 November 1755.
• Krakatau, Indonesia – 27 August 1883.
• Enshunada Sea, Japan – 20 September 1498.
• Nankaido, Japan – 28 October 1707.
• Sanriku, Japan – 15 June 1896.
• Northern Chile – 13 August 1868.

2004

Jan