The Difference Between Clean and Green Energy, and Why It Matters

Talking about energy and the environment can get a little complicated. Words like “clean,” “green,” “renewable,” and “sustainable” get used interchangeably, but really, they each have specific meanings. And it doesn’t help that, because of growing interest in green technology more broadly, a lot of companies have adopted these terms more as buzzwords than as actual descriptions of their policies. So, with that in mind, let’s talk about some of these terms around energy and the environment, what they mean, and what we should be looking for when it comes to a sustainable future.

Clean, Green, or Renewable?

The main terms that are used around energy are clean, green, and renewable. These terms are often used interchangeably even though they have different meanings, which can make understanding what’s being talked about a little challenging. Also, there are some small disagreements about which energies count under which umbrella, which only makes it more confusing. That said, here’s a basic rundown of each term.

Clean energy is energy that doesn’t generate emissions or pollution to generate or use. This term is usually very focused on emissions. Just because an energy is described as “clean” does not necessarily mean it is renewable—it just means that it isn’t generating greenhouse gas emissions that contribute to climate change.

Using the term “clean” can be a little tricky because it doesn’t necessarily address the holistic environmental impact.  One example of this is the discussion around whether nuclear power is a clean energy. A nuclear power plant does not generate greenhouse gas emissions, which means that some may count nuclear power as “clean.” But the process of mining uranium has a negative environmental impact and can generate emissions.  Also, the various radioactive waste products that come from nuclear power plants, while not greenhouse gas emissions, are absolutely pollutants. So, while the process of nuclear fission doesn’t generate greenhouse gas emissions like burning oil does, the nuclear power plant itself isn’t all the way “clean.”

Renewable energy comes from “resources that rely on fuel sources that restore themselves over short periods of time and do not diminish,” according to the EPA. This contrasts with non-renewables like oil and coal, which are finite resources that are diminishing every day. Most renewable energy sources are a big improvement from fossil fuels, but just because an energy is “renewable” doesn’t mean that it is free of environmental concerns.

A good example of this is a biomass power plant. Biomass power plants share some similarities with fossil fuel power plants in that they run on combustion, or burning, of a material to generate electricity. But instead of using non-renewable fossil fuel sources, biomass plants burn accumulated renewable materials like agricultural residue, waste material, manure, and so on. The fuel for biomass plants can be sustainably produced, but the combustion process still emits greenhouse gasses. So while switching to biomass from fossil fuels is a step in the right direction, it isn’t without concern when it comes to climate change.

Green energy is a subset of renewable energy that does not have significant environmental impacts to generate or use. In order for an energy source to count as “green,” the resource used must be renewable and the whole process of using the energy needs to provide the greatest environmental benefit. This comes with the understanding that every source of energy, even green sources, come with some environmental trade-off, but the idea is that any harm is limited as much as possible.

Green energy is the most specific of the terms and requires a holistic investigation of the effects of the energy source, with the goal of limiting emissions and ensuring a healthy environment long-term.

Why Do These Words Matter?

Parsing out these terms may not seem important, but these words and the categories they represent drive the way we talk about policy and climate change. Whether we focus on moving towards green or clean energy actually has a huge impact on the energy sector. A perfect example of this is with the recent controversy at the COP28 Climate Change Conference.

The president of the conference this year was Sultan Al Jaber, an Emirati politician with ties to both the renewable energy industry and, notably, the oil and gas industry. It’s well known that a significant part of the Emirati economy is supported by the oil industry, and Al Jaber himself is the CEO of the Abu Dhabi National Oil Company. Al Jaber’s appointment as president of COP28 was seen by many as a blatant conflict of interest for a lot of reasons, but one specific concern was his commitment to carbon capture technology for oil and gas power plants.

Carbon capture technology aims to prevent emissions from reaching the atmosphere by “scrubbing” them from the air at the point of generation. So basically, a coal plant can install carbon scrubbers to clean the air coming out of the plant and prevent carbon from entering the atmosphere. In theory, if these carbon capture systems on a coal plant were 100% effective (and they’re typically only 90% effective), it could be argued that the coal plant would then be “clean energy.”

The issue, though, is that these carbon systems cannot currently keep up with the emissions being generated. A study of Al Jaber’s own oil company showed that it would take their carbon capture system 340 years to capture the emissions the company generates by 2030. Supporting carbon capture may make an energy company appear to be clean, but the reality isn’t so neat.

The real problem with large-scale support of carbon capture is that it encourages continued use of fossil fuels for energy. In fact, some consider the focus on carbon capture as a way to help the fossil fuel industry grow. Limiting the amount of carbon dioxide going into the air is a huge part of stopping climate change, but it’s not the only thing we need to consider. Even if we stopped the emissions entirely, the extraction of fossil fuels causes massive environmental damage, and those fuels are still, at the end of the day, finite resources. And if the carbon capture technology isn’t even that effective, the support of carbon capture for oil plants has the potential to just be an exercise in greenwashing.

This is why the difference between clean and green energy is important. Whether an energy is green or clean could make a big difference in its effects on the environment over the long-term. Clean energy is a step in the right direction toward limiting climate change, because we absolutely need to cut emissions as quickly as possible. But the better long-term path for the planet lies with renewable green energy like solar and wind.