Renewable Energy vs. Sustainable Energy: What’s the Difference?

Sustainability / February 13, 2023

As the world transitions to a green future, terms like renewable, sustainable, and alternative are used synonymously by experts and non-specialists alike. But while these phrases may share similarities, they do have different meanings. For instance, in the discussion of renewable energy vs. sustainable energy, both terms have vital—albeit subtle—nuances.

So, let’s define these terms to help you distinguish the differences when comparing renewable vs. sustainable energy.

Renewable Energy Defined

Renewable energy is usable energy derived from a naturally occurring source or process that can be replenished faster than consumed. This constant replenishment over time is where the term renewable originates.

For example, the sun and wind are renewable sources that will always be available in some form—although they may be time and weather dependent. Humanity can harness it without ever using it all up.

But what about oil and coal? Don’t they naturally occur?

They do, but not at a rate faster than they’re consumed. That is the key distinction. As John Hopkins University notes:

“Renewable energy is defined by the time it takes to replenish the primary energy resource, compared to the rate at which energy is used. This is why traditional resources like coal and oil, which take millions of years to form, are not considered renewable. On the other hand, solar power can always be replenished, even though conditions are not always optimal for maximizing production.”

Unlike fossil fuels, renewables produce little to no greenhouse gas emissions. They tend to be abundant and replenish naturally. And as time passes, these technologies are becoming increasingly more energy efficient and cost-effective.

Examples of renewable energy include:

Solar – With this renewable process, solar panels convert radiant heat and light from the sun into electricity. Typically this occurs in one of two ways: (directly) using photovoltaic panels or (indirectly) via concentrated solar energy systems. That heat is then used as a direct heating or cooling source or to produce electricity.
Wind – Wind farms utilize massive turbines to generate electricity by converting wind’s kinetic energy into mechanical energy. The wind is considered renewable because it’s constantly generated by the sun’s heat, the earth’s rotation, and atmospheric pressure differences.
Hydropower – One of the original sources of electricity, hydropower harnesses the energy of falling or flowing water, often from rivers or streams moving from higher to lower elevations. This typically involves a turbine or dam that converts it into kinetic energy. It was only recently surpassed by the wind as the primary renewable in the US in 2019. Today, it accounts for 6% of domestic utility-scale electricity generation and 32% of renewable electricity generation.
Geothermal – Geothermal energy processes capture heat generated by the earth’s core in regions with high volcanic and/or tectonic activity. Steam or hot water is extracted from a geothermal reservoir, which is then used to generate electricity. Today, the United States is the world’s largest producer of geothermal energy, producing 16.7 billion kilowatt hours (kWh) of geothermal energy annually.
Ethanol – Ethanol is a renewable biomass energy source from crops like corn and sugarcane. These crops can be grown, harvested, and replanted cyclically, making them renewable. Although it may release harmful pollutants and greenhouse gases when used as fuel, ethanol is still considered a more eco-friendly substitute to fossil fuels.
Tidal – Currently, tidal energy only represents a small source of energy production. However, it’s still considered an important renewable energy source for the future. Tidal energy systems like tidal turbines and barrages operate similarly to a hydropower system, harnessing the kinetic energy of ocean tides to generate electricity.

Sustainable Energy Defined

Here is where the nuance of the discussion begins to take shape: All sustainable energy sources are renewable, but not all renewables are deemed sustainable. At its essence, sustainable energy is an energy source that can be consistently used without jeopardizing its availability for future generations.

To be sustainable, energy production must be safely and efficiently obtained, distributed, and consumed. It must meet both society’s short and long-term needs. To that end, it should:

Preserve the natural environment – Producing as little waste and emissions as possible without harming biodiversity.
Empower society to thrive – Building and operating installations according to laws and regulations, meeting safety work standards, and not negatively impacting a community.
Contribute to the local economy – Supporting local communities (especially rural or poor communities) by increasing electrical access needed to power their economies.

So, biofuel is regularly cited as an example of a fuel source that is renewable but not sustainable. That’s because growing the necessary plants uses up environmental resources, and the consumption of this fuel still results in the emissions of climate-affecting greenhouse gases.

Sustainability May Be In the Eye of the Beholder

The sustainable vs. renewable conversation can sometimes lead to ambiguity and uncertainty, resulting in gray areas regarding what is or isn’t considered sustainable.

For instance, despite being widely recognized as sustainable energy sources, solar and wind energy may only meet some criteria to be considered truly sustainable. Some of the shortcomings of these power sources include:

Can’t provide consistent power
Are incapable of providing enough power to meet domestic demand
Components are entirely dependent on the use of finite rare earth resources
Can negatively impact biodiversity and communities
Are not easily disposed of, if at all
Can cause noise and visual pollution

Nuclear energy is often excluded in sustainable energy lists, even though it provides consistent power, has higher, more efficient energy density, requires less land, and has much lower CO2 emissions.

Alternative Energy: A Third Pathway

An exciting new avenue has emerged with novel technologies and energy sources -- alternative energy. In particular, two potential alternative energy sources show significant promise:

Hydrogen – Hydrogen is the fuel of the future—a potential renewable source of electric power that emits zero carbon emissions. And, with the development of turquoise hydrogen production via pyrolysis, it’s now possible to split methane without any greenhouse gas emissions.
CNG – Compressed natural gas is a highly pressurized and dense fuel source that is cleaner, cheaper, and more environmentally friendly than gas or diesel fuels. Furthermore, if CNG is produced from renewable sources like biomethane, it would be a sustainable energy source.

As technology continues to improve, such innovations within the energy sector have the potential to disrupt sustainability's status quo completely.

Choose FASTECH For Renewable Energy Infrastructure Solutions

With the country transitioning to focus on future sustainability, individuals and businesses alike are encouraged to contribute by investing in renewable energy solutions.

At FASTECH, we provide end-to-end energy infrastructure solutions, focusing on alternative energies like hydrogen, CNG, RNG, LNG, and propane. Our goal is to make the energy industry safer, greener, and more efficient.

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