5.1 FUELS 98 RENEWABLE AND NON-RENEWABLE ENERGY SOURCES To make sure that everyone in the world has access to clean and safe energy, we need to understand energy consumption, its impact around the world today and how this has changed over time. The world lacks safe, low-carbon, and cheap large-scale energy alternatives to fossil fuels so, until we scale up those alternatives, the world will continue to face two energy problems: the lack of access to sufficient energy for many people, and climate change and other health impacts such as air pollution. Types of energy sources Earth s energy resources can be divided into two main categories: Non-renewable energy sources, also called finite resources, which are available in limited supplies, usually because they take a long time to replenish; Renewable energy sources, which derive from natural processes that are replenished constantly, such as sunlight, wind, rain, tides, waves, and geothermal heat. to be reliant on: dipendere da challenge: sfida face: affrontare to replenish: rigenerare to shift: passare At present, the main energy sources used are nonrenewable fossil fuels and, while research is constantly being done to discover new ones, we are still very reliant on these traditional sources. Energy transition Energy transition refers to the global energy sector s shift from fossil-based systems of energy production and consumption to renewable energy sources. At present, the main energy sources used are non-renewable fossil fuels: our need for energy is growing and we are still reliant on traditional sources. Shifting towards green energy is supposed to play a critical role in addressing some of the most prominent contemporary challenges the world is facing. The result will be the reduction of greenhouse gas emissions through various forms of decarbonisation. What is Decarbonisation? Decarbonisation refers to the process of reducing carbon dioxide emissions resulting from human activity in the atmosphere and eventually, eliminate CO2 emissions. To achieve deep decarbonisation, we need to rethink how we produce and consume energy and operate a radical switch to renewable and low carbon energy sources. In order to reach this goal, all aspects of the economy must change, from how energy is generated, how we produce and deliver goods and services, to how land is managed. Carbon-free or carbon-neutral? Most renewable energy sources are carbon-free, meaning they do not emit any carbon dioxide when they generate energy. On the other hand, renewable energy sources, like biomass and biofuels, are considered carbon-neutral because they emit carbon dioxide when they are burnt, but their overall carbon emissions balance the carbon dioxide originally removed by plants from the air. Either solution is fine for achieving decarbonisation. 214 Think green MechPower.indb 214 30/01/24 17:09