— Ch. 1 · Measuring The Invisible Cost —
Life-cycle greenhouse gas emissions of energy sources.
~3 min read · Ch. 1 of 6
The Intergovernmental Panel on Climate Change released a harmonized study in 2014 that analyzed hundreds of scientific papers. This massive review calculated the global warming potential for major electricity sources worldwide. Researchers used carbon dioxide equivalent units to express these findings per kilowatt hour generated. Coal emerged as the worst emitter with a median value of 820 grams of carbon dioxide equivalent. Natural gas followed closely behind at 490 grams per kilowatt hour. Solar and wind technologies appeared much lower on this scale. Nuclear power sat near the bottom with a median of 12 grams. Hydropower showed extreme variability ranging from 1 gram to over 2000 grams depending on specific site conditions.
Data Gaps And New Research
Individual studies after 2014 reveal wide ranges of estimates due to differing methodologies. Some low-end analyses leave parts of the life cycle out entirely. High-end assessments often make unrealistic assumptions about energy usage during production phases. Geothermal research in Italy found emissions higher than previously thought during the 2020s. Ocean energy technologies remain relatively new with few conducted studies available. A 2020 assessment of 180 ocean technologies found global warming potential varied between 15 and 105 grams. Subsea tidal kite technologies showed a median value of 23.8 grams in preliminary studies. These figures sit slightly higher than the 2014 IPCC report mean of 17 grams. Maintenance impacts appear significant yet frequently underestimated by current models.