Renewable energy: what is it and why do we need it

Any discussion of climate change is bound to point to the fact that the use of renewable energy can prevent the worst effects of global warming. The reason is that renewable energy sources such as solar and wind do not emit carbon dioxide and other greenhouse gases that contribute to global warming.

For the past 150 years, humans have largely relied on coal, oil, and other fossil fuels to power everything from light bulbs to cars and factories. As a result, the amount of greenhouse gases emitted when these fuels are burned has reached exceptionally high levels.

Greenhouse gases trap heat in the atmosphere that could otherwise escape into space, and average surface temperatures are rising. Thus, global warming occurs, followed by climate change, which also includes extreme weather events, displacement of populations and habitats of wild animals, rising sea levels and a number of other phenomena.

So, the use of renewable energy sources can prevent catastrophic changes on our planet. However, despite the fact that renewable energy sources seem to be constantly available and practically inexhaustible, they are not always sustainable.

Types of renewable energy sources

1. Water. For centuries, people have harnessed the power of river currents by building dams to control the flow of water. Today, hydropower is the world’s largest source of renewable energy, with China, Brazil, Canada, the United States, and Russia being the top producers of hydropower. But while water is theoretically a source of clean energy replenished by rain and snow, the industry has its drawbacks.

Large dams can disrupt river ecosystems, damage wildlife, and force the relocation of nearby residents. Also, a lot of silt accumulates in places where hydropower is generated, which can compromise productivity and damage equipment.

The hydropower industry is always under the threat of drought. According to a 2018 study, the western U.S. has experienced 15 years of carbon dioxide emissions up to 100 megatons higher than normal for XNUMX years as utilities have been forced to use coal and gas to replace hydropower lost due to drought. Hydropower itself is directly related to the problem of harmful emissions, as decaying organic material in reservoirs releases methane.

But river dams are not the only way to use water to generate energy: around the world, tidal and wave power plants use the natural rhythms of the ocean to generate energy. Offshore energy projects currently produce about 500 megawatts of electricity – less than one percent of all renewable energy sources – but their potential is much higher.

2. Wind. The use of wind as a source of energy began more than 7000 years ago. Currently, wind turbines that generate electricity are located all over the globe. From 2001 to 2017, the cumulative wind power generation capacity worldwide increased by more than 22 times.

Some people frown on the wind power industry because tall wind turbines ruin the scenery and make noise, but there’s no denying that wind power is a truly valuable resource. While most wind power comes from land-based turbines, offshore projects are also emerging, most of which are in the UK and Germany.

Another problem with wind turbines is that they pose a threat to birds and bats, killing hundreds of thousands of these species every year. Engineers are actively developing new solutions for the wind energy industry to make wind turbines safer for flying wildlife.

3. The sun. Solar energy is changing energy markets around the world. From 2007 to 2017, the total installed capacity in the world from solar panels increased by 4300%.

In addition to solar panels, which convert sunlight into electricity, solar power plants use mirrors to concentrate the sun’s heat, producing thermal energy. China, Japan and the US are leading the way in solar transformation, but the industry still has a long way to go as it now accounts for about two percent of total US electricity generation in 2017. Solar thermal energy is also used worldwide for hot water, heating and cooling.

4. Biomass. Biomass energy includes biofuels such as ethanol and biodiesel, wood and wood waste, landfill biogas, and municipal solid waste. Like solar energy, biomass is a flexible source of energy, capable of powering vehicles, heating buildings and generating electricity.

However, the use of biomass can cause acute problems. For example, critics of corn-based ethanol argue that it competes with the food corn market and supports unhealthy agricultural practices. There is also debate about how smart it is to ship wood pellets from the US to Europe so they can be burned to generate electricity.

Meanwhile, scientists and companies are developing better ways to convert grain, sewage sludge and other sources of biomass into energy, seeking to extract value from material that might otherwise go to waste.

5. geothermal energy. Geothermal energy, used for thousands of years for cooking and heating, is produced from the Earth’s internal heat. On a large scale, wells are being laid to underground reservoirs of steam and hot water, the depth of which can reach more than 1,5 km. On a small scale, some buildings use ground source heat pumps that use temperature differences several meters below ground level for heating and cooling.

Unlike solar and wind energy, geothermal energy is always available, but it has its own side effects. For example, the release of hydrogen sulfide in springs may be accompanied by a strong smell of rotten eggs.

Expanding the Use of Renewable Energy Sources

Cities and countries around the world are pursuing policies to increase the use of renewable energy sources. At least 29 US states have set standards for renewable energy use, which must be a certain percentage of the total energy used. Currently, more than 100 cities around the world have reached 70% renewable energy use, and some are striving to reach 100%.

Will all countries be able to switch to fully renewable energy? Scientists believe that such progress is possible.

The world must reckon with real conditions. Even aside from climate change, fossil fuels are a finite resource, and if we want to continue living on our planet, our energy must be renewable.

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