[Micele]

De slechtste payback was 354 dagen, de beste 64 dagen, dit uit een studie van 14 windturbines:

https://www.omicsonline.org/open-acc....php?aid=74577

Life Cycle Analysis of the Embodied Carbon Emissions from 14 Wind Turbines with Rated Powers between 50 Kw and 3.4 Mw
Emily A. Smoucha1,2, Kate Fitzpatrick2, Sarah Buckingham3 and Oliver G.G. Knox4*
1 School of Geosciences, Edinburgh University, UK

Received Date: March 11, 2016; Accepted Date: June 10, 2016; Published Date: June 15, 2016

Citation: Smoucha EA, Fitzpatrick K, Buckingham S, Knox OGG (2016) Life Cycle Analysis of the Embodied Carbon Emissions from 14 Wind Turbines with Rated Powers between 50 Kw and 3.4 Mw. J Fundam Renewable Energy Appl 6:211.doi:10.4172/20904541.1000211

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Results

Life cycle emissions

The lifecycle emissions of each turbine were calculated as the sum of the manufacture, transportation, and installation emissions as set out by the parameters listed in the methodology. As well as total lifecycle emissions, the carbon intensity, carbon payback period, carbon payback period as a percentage of lifespan and the total offset emissions of each turbine were calculated (Table 3). Additionally, the emissions of each turbine were broken down by sector to determine what percentage manufacture, transportation, and installation contributed to the total emissions.

Rated Power Electricity generated over lifetime (MWh) Total emissions (tCO2eq) Carbon intensity (kg/MWh) Payback period (days) Payback period as percentage of lifetime
(%) Offset emissions (tCO2eq)
50 kW 2260 59 26.1 312 4.3 1317
80 kW 3616 58 16 192 2.6 2144
100 kWA 4520 61 13.4 160 2.2 2692
100 kWB 4520 134 29.5 354 4.9 2619
250 kW 11300 148 13.1 157 2.1 6734
500 kW 22601 274 12.1 145 2.0 13490
900 kW20 years 40681 289 7.1 85 1.2 24486
900 kW25 years 50852 289 5.7 85 0.9 30680
2 MW kW20 years 90403 937 10.4 124 1.7 54119
2 MW kW25 years 113004 937 8.3 124 1.4 67883
2.05 MWA 92663 641 6.9 83 1.1 55791
2.05 MWB 92663 747 8.1 97 1.3 55685
2.3 MW20 years 103964 859 8.3 99 1.4 62455
2.3 MW25 years 129955 859 6.6 99 1.1 78283
3. MW 135605 1046 7.7 92 1.3 81538
3.2 MW 144645 957 6.6 79 1.1 87132
3.4 MW 153685 824 5.4 64 0.9 92770

Table 3: Results of lifecycle analyses for each turbine. Subscripts “A” and “B” differentiate turbines of the same rated power. Subscript “20 years” details the emissions information calculated based on a turbine lifespan of 20 years, while subscript “25 years” represents a lifespan of 25 years.

The general trend showed that lifecycle emissions increase as the rated power of the turbine increases (Table 3). However, there were some exceptions to this trend. The smallest turbine examined, a 50 kW turbine had lifecycle emissions of 58.9 tCO2eq, which were slightly higher than an 80 kW turbine with 57.9 tCO2eq. Turbines of similar size did not always result in the same lifecycle emissions. For 100 kW generator turbines, 100 kWB had over twice the lifecycle emissions of turbine 100 kWA with 60.5 tCO2eq and 133.5 tCO2eq, respectively. Similarly, the 2 MW turbine had nearly 50% more emissions than the 2.05 MWA turbine and 25% more emissions than 2.05 MWB turbine, which emitted 640 and 750 tCO2eq, respectively, during their lifecycles. The highest CO2eq emissions resulted from the production of a 3 MW turbine, which emitted 221.5 tCO2eq, and not from the production of the largest turbine (3.4 MW).

Carbon intensity

Results indicate that carbon intensity was highest among the lower power rated turbines (Table 3). For turbines rated 500 kW and under, the carbon intensity was greater than 12.1 kgCO2eq/MWh, and by comparison, no turbines over 500 kW had a carbon intensity greater than 10.4 kgCO2eq/MWh. Due to their differences in total carbon emissions, the carbon intensities of the 100 kW turbines were different with 29.5 kgCO2eq/MWh for 100 kWB, compared to 13.4 kgCO2eq/ MWh for 100 kWA. 100 kWB also had the greatest carbon intensity (29.5 kgCO2eq/MWh), and, by comparison, the lowest carbon intensity was that of the 3.4 MW turbine, with only 5.4 kgCO2eq/MWh. Despite a 3,400% greater power rating, the carbon intensity of the 3.4 MW turbine was only 18% that of the 100 kWB turbine.

Due to its greater total emissions, the 2 MW turbine had nearly 50% greater carbon intensity than the 2.05 MWA and nearly 30% greater than the 2.05 MWB (Table 3).

Carbon payback period

The carbon payback period for each turbine showed the number of days that must be spent generating electricity to offset emissions generated during manufacture, transport, and installation of the turbine (Table 3). The longest payback period was for the 100 kWB turbine, with 354 days to offset its production emissions.

All turbines less than 500 kW took over 145 days to offset their emissions, and no turbine with a power rating above 500 kW took more than 125 days to payback its emissions.

The two 100 kW turbines had drastically different payback periods. The 100 kWA turbine, with carbon emissions only 45% of those from the 100 kWB turbine, had a payback period under 161 days, compared to 354 for 100 kWB.

The 3.4 MW turbine, which had the highest production potential rating, had the shortest payback period, with 65.5 days. It took the 3.4 MW turbine only 21% of the time it took the 50 kW turbine to pay back its emissions.

The 2.05 MWB turbine emitted 106.3 tonnes of CO2eq more than the 2.05 MWA turbine over its lifetime, but added only 14 days to offset the emissions. Despite their nearly 1 MW range in powers and 300 tCO2eq emissions over their lifespans, the 2.05 MW20 years, 2.3 MW, and 3 MW turbines all offset their emissions within a week of one another.

Carbon payback period as a percentage of lifetime

The carbon payback period was calculated to determine what amount of the turbine’s operational life is dedicated to offsetting its production emissions. As all the turbines had a minimum expected lifespan of 20 years, the trend for payback percentage was the same as for the payback period; when the payback period increased, so did the percentage of the lifetime. The 100 kWB turbine had the highest percentage of its lifetime spent offsetting its production emissions with a value of 4.9% (Table 3).

All turbines under 500 kW required 2% or more of their lifetime to offset their production emissions. When the turbines were larger than 500 kW, the carbon payback period was 1.4% or lower. The 3.4 MW turbine only required 0.88% of its 20 year lifespan to offset its emissions.

Three turbines were listed as having extendable lives from 20 years to 25 years. Increasing the lifespan by 25% did not affect the payback period itself, but it did reduce the percent of the lifetime that was spent offsetting production emissions. Increasing the lifespan of each turbine resulted in reductions in the payback percentage by approximately 20% each.

Offset emissions

Offset emissions depend on the rated power of the turbine and the lifecycle production emissions. Offset emissions increased as the rated power of the turbine increased, thus the 50 kW turbine had the lowest offset emissions at 1,317 tCO2eq whereas the 3.4MW turbine was more than 70 times that at 92,770 tCO2eq.

Despite their different carbon intensities and payback periods, the two 100 kW turbines had similar total offset emissions, with 2,692 tCO2eq and 2,619 tCO2eq for the100 kWA and 100 kWB turbine, respectively.

The amount of CO2 saved over 20 years by installing either of the 2.05 kW turbines was greater than the amount of CO2 that could be saved by installing the 2 MW turbine combined with the 50 kW turbine.

Increasing the lifespan of the 900 kW, 2 MW, and 2.3 MW turbines, from 20 to 25 years, drastically increased the amount of emissions each could offset over their lifetimes (Table 3). The five-year increase in lifespan increased the total emissions the 900 kW, 2 MW and 2.3 MW turbine could offset by 25%, which equated to an additional 15,828 tCO2eq for the 2.3 MW turbine.

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Ondertussen bouwt men windturbines van > 10 MW...
Een tiental tussen 5 en 9,5 MW:
https://www.windpowermonthly.com/10-biggest-turbines