There was a recent updated analysis of various life-cycle energy impact measurements for fossil fuels, nuclear, solar and wind.
Lifetime CO2 Emissions per Kilowatt-Hour
Solar is 50% worse than nuclear for lifetime CO2 emissions per kilowatt-hour. Nuclear and wind tie for the best.
The study finds each kilowatt-hour of electricity generated over the lifetime of a nuclear plant has an emissions footprint of 4 grams of CO2 equivalent (gCO2e/kWh). The footprint of solar comes in at 6gCO2e/kWh and wind is also 4gCO2e/kWh. The best solar technology in the sunniest location has a footprint of 3gCO2/kWh, some seven times lower than the worst solar technology in the worst location (21gCO2/kWh). If we were running a civilization on ground based solar we would use a lot more bad locations.
In contrast, coal CCS (109g), gas CCS (78g), hydro (97g) and bioenergy (98g) have relatively high emissions
Energy Returned on Energy Invested
It is better to get greater amounts of energy generation that the energy needed to build and operate power plants. Energy Returned on Energy Invested (EROI) is the metric for this. Inverting EROI is energy embodied.
11% of the energy generated by a coal-fired power station is offset by energy needed to build the plant and supply the fuel, as the chart below shows. This means coal plants have an EROI of 9:1.
Nuclear power is twice as good as coal, with the energy embedded in the power plant and fuel offsetting 5% of its output, equivalent to an EROI of 20:1. Wind and solar currently are better at 2% and 4% respectively, equivalent to EROIs of 44:1 and 26:1.
Typical solar currently generates about 350 watts per standard panel module. Florida Power & Light wants to install solar farms with 30 million panels. This would be 10,500 megawatts. This would only generate the power of three gigawatts of nuclear power because solar generates about 25% of capacity versus 90% capacity for nuclear energy.
By 2050, a 2017 Nature study forecasts that EROI will get worse for new energy projects. It might be tougher to extract resources for fossil fuels and solar and wind would be built in inferior locations.
There is a video from China touting its energy megaprojects. However, the video also gives a clearer sense of the scale of materials needed for coal, solar, wind and nuclear.
Each solar unit might only generate 1 kilowatt for smaller 3 square meter mirrors or panels or tens of kilowatts for long troughs. However, tons of steel and cement are needed for each kilowatt.
Wind versus Nuclear
It would take about eight hundred five-megawatt wind turbines to generate the energy of one gigawatt nuclear plant. Each wind turbine has about 875 tons of steel and cement. This includes the foundation. Energy Skeptic had an analysis of a single wind turbine.
This is why wind power uses about 5 to 10 times more material to generate the same amount of power as nuclear. Solar also uses a multiple of the land and materials to generate the same power as nuclear.
Each wind turbine takes about 3 weeks to build from excavation to operation
40 to 100 geopiers installed for stability, weight unknown. These are part of the foundations and the amount of foundation various based on soil conditions.
Set 96,000 pounds of reinforcing steel rebar = 48 tons
53 concrete trucks pour foundations. If each truck can haul 8 cubic yards at 2538 lbs/yard * 53 = 1,076,112 pounds = 538 tons
Move 1,500 cubic yards of soil @ 2,200 lbs per cubic yard = 3.3 million pounds = 1,650 tons
3 blades : each 173 feet long and 27,000 pounds for 81,000 pounds = 40.5 tons
8 truckloads to deliver turbine components
Nacelle: weight 181,000 lbs = 90.5 tons with the generator, gearbox, and rotor shaft
Hub: weight unknown
Base tower height 53 feet 11 inches, weight 97,459 lbs = 48.7 tons
Mid tower height 84 feet 6 inches, weight 115,587 lbs = 57.8 tons
Top tower height 119 feet, weight 104,167 lbs = 52 tons
Final tower height to blade tip when fully extended 442 feet
Nature – Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modeling.
SOURCES- Nature, Energy Skeptic, Youtube CGTN
Written By Brian Wang, Nextbigfuture.com