John Phipps: Is So-Called 'Green Energy' Truly Green?

It’s not easy being green.

“One question keeps coming to mind when everyone keeps talking about green energy such as solar and wind. What is the true cost of manufacturing these green energies (by-products/waste). Are they truly green? I'm all for the idea, just wish they would explain it better.” - That’s from Wayne Linzmeier, in Auburndale, Wisc.

This is a great question to clear up confusion about what green means. The term green is not a scientific term, and it is not tied to a specific standard. Basically, it refers to greenhouse gas (GHG) emissions, most importantly carbon dioxide. The fewer GHG emissions the greener the technology.

There are no absolutely emission-free energy sources, but there is a wide range that gives perspective. To compare energy emissions, we use an analysis called lifecycle assessment, shown here. Beginning with the raw materials extraction, like coal, uranium, iron, or lithium, all the emissions from those activities are calculated.

he same for emissions from manufacturing, transportation, actual operating emissions, and disposal. These are the emission sources critics of wind and solar often cite. Lifecycle assessment studies, of which there have been hundreds, show how solar construction material mining emissions, for example, are real but minuscule in terms of electricity generated.

Here is how generation technologies rank, using identical methodology. The units are grams of CO2 per unit of electricity generated. Those at the top are the greenest – lowest emissions. Note it does not compare costs. Cost is not the point for greenness, so to speak. I will compare those another time.

Again, these are lifecycle totals – from blueprints for a plant back to bare dirt after decommissioning. The disposal exception is hydro, since dams are deemed permanent. The most common solar technologies are highlighted and represent most installations. For fossil fuels, CCS refers to carbon capture and storage, but out of 224 coal plants and 3400 gas generators in the US there are less than ten employing some form of CCS. It would make a whacking difference in emissions.

Even with CCS, however, combustion emissions keep their lifetime emissions from coming anywhere close to wind, solar, and surprisingly, nuclear power. Solar and wind aren’t perfectly green, but when all lifecycle emissions are totaled, they are as green as we can achieve now.