For more than a century, burning fossil fuels has generated most of the energy required to propel our cars, power our businesses, and keep the lights on in our homes. In 2018, oil, coal, and gas provide for about 80% of our energy needs.

They are called fossils because they come from the very slow decomposition of living elements (mostly plants) several million years ago. Their quantity is limited on Earth, their extraction causes their exhaustion. It is more or less easy to extract this energy, depending on the geological conditions and the evolution of techniques.

These materials are used in burning them, which produces carbon dioxide (CO2) and is a major cause of global warming.

And we’re paying the price. Using fossil fuels for energy has resulted in an enormous toll on humanity and the environment, not only with global warming but also with an increase in air and water pollution. That’s in addition to the negative impacts of petroleum-based products such as plastics and chemicals.

Shortlist of fossil fuels disadvantages:

• Land degradation:
  Destruction of landscapes & ecosystems (due to unearthing, processing, moving underground fossil fuel deposits and infrastructures like wells, pipelines, access roads, waste disposal, …), like swaths of terrain, forests, and whole mountaintops to expose underground coal or oil. the nutrient-leached land will never return to what it once was. The destruction of critical wildlife habitats (land crucial for breeding and migration) leading animals to leave and even end up suffering, as they’re often forced into less-than-ideal habitat and must compete with existing wildlife for resources.
• Water pollution :
  They pollute waterways and groundwater (due to leaks & oil spills during extraction or transport & acid runoff), can cause the contamination of drinking and freshwater sources and produce enormous volumes of wastewater laden with heavy metals, radioactive materials, and other pollutants (due to drilling, mining, and fracking).  Those pollutants are connected to health problems like cancers, birth defects, neurological damage, and much more.
• Emissions :
  They emit harmful air pollutants like benzene (linked to childhood leukemia and blood disorders) and formaldehyde (a cancer-causing chemical). People are exposed daily to toxic air pollution from active oil and gas wells, from transport, and processing facilities (12 million people concerned in the US). Using fossil fuels also release carbon dioxide (CO2), and poisonous molecules like mercury (💀), sulfur dioxide (linked to acid rains), carbon monoxide (💀), nitrogen oxide (linked to smog and respiratory illness on hot days)
• Ocean acidification :
  When we burn fossil fuels, we change the ocean’s basic chemistry, making it more acidic. Our seas absorb as much as a quarter of all man-made carbon emissions. Since the start of the Industrial Revolution (and our coal-burning ways), the ocean has become 30 percent more acidic. As the acidity in our waters goes up, the amount of calcium carbonate (used by countless marine organisms to form shells) goes down. This can slow growth rates, weaken shells, and imperil entire food chains.
• Limited resources :
  Last but not least, the proven world reserves of non-renewable energies (fossils and uranium) could be estimated in 2015 at 946 billion Tonnes of Oil Equivalent (T.O.E.), or 80 years of production at the current rate. This duration varies depending on the kind of energy used: 51 years for oil, 53 years for natural gas, 114 years for coal.

The power sector currently accounts for around 40 percent of annual greenhouse gas emissions to the atmosphere, making it the highest-emitting sector, followed by industry and transportation.

Sources: NRDC.org, Drawdown.org & International Energy Agency

Now that we know that the resources we mainly use are limited, their use mainly responsible for climate change and pollutions, we need to focus on reducing our energy consumption to our real needs, as well as to push the development and use of renewable energy.

The good news is that many alternatives already exist, a lot of them actually, and their appeal no longer needs to be proven.

Also, renewable energy costs are constantly falling on a year to year basis, while fossil fuel from new sources is significantly more difficult to extract, which will cause the carbon-based fuels to rise in cost.

As sources of energy, the solutions are both in the centralized (like on-shore wind turbine) and decentralized spectrum (like solar-rooftop), some can be implemented in large scale (cities, countries, continents), and others in a much smaller scale (a district, a community, a building, a business, a family or even a person).

Each works differently and comes with its own challenges :

• What are the resources needed for production?
• What is its flexibility to meet the demand for energy?
• Would its location meet the necessity of energy?
• How to store the extra production of energy?
• And to what extent is this source of energy renewable, better for the environment and humankind’s future?

Finally, the evolution of the electricity grid and the accessibility to energy-saving technologies are important aspects of renewable energy development in our century.