ENVIRONMENTAL IMPACTS OF ELECTRICITY PRODUCTION

TECHNOLOGIES IN SLOVENIA

In this chapter, a comparison of the environmental impacts of the produced 1 kWh of electricity for

various technologies available in Slovenia is done. Technologies are also positioned according to the

Slovene energy mix SI-MIX and the European energy mix of the EU28. All global, regional and local

environmental indicators are considered, which were later used in the interpretation of results for

individual electricity distributors in Slovenia.

Table 1: The discussed technologies of electricity generation in Slovenia and the shares in the

Slovenian energy mix

TECHNOLOGY SHARE IN SI-MIX

Biogas 0,88

Biomass solid 0,75

Hard coal 2,51

Heavy fuel oil 0,04

Hydro 30,5

Lignite 27,8

Natural gas 3,16

Nuclear 32,96

Photovoltaics 1,34

Waste to electricity 0,04

Wind 0,02

Table 2: Values of all considered environmental indicators for the production of 1 kWh of electricity

for the technologies concerned

CML2001-JAN. 2016

EU-28 SI-MIX BIOGAS BIOMASS

HARD COAL

HFO HYDRO LIGNITE NATURAL GAS

NUCLEAR

PV WASTE WIND

ADP [KG SB-EQUIV.]

1,8E-07 1,6E-07 7,9E-07 7,5E-08 6,0E-09 8,1E-08 2,1E-07 3,3E-09 5,2E-08 3,4E-08 4,0E-06 6,7E-08 4,5E-07

AP [KG SO2-EQUIV.]

1,3E-03 2,2E-03 4,1E-03 2,4E-03 1,9E-03 9,8E-03 1,1E-05 2,6E-03 3,7E-04 3,0E-05 2,9E-04 7,5E-04 2,5E-05

EP [KG PHOSPHATE-EQUIV.]

1,2E-04 1,3E-04 9,1E-04 5,0E-04 2,6E-04 3,2E-04 1,3E-06 2,9E-04 5,1E-05 5,7E-06 2,3E-05 1,5E-04 2,8E-06

FAETP INF. [KG DCB-EQUIV.]

8,9E-04 7,6E-04 1,2E-03 2,0E-03 6,2E-04 1,9E-02 3,6E-06 5,0E-04 2,9E-04 1,5E-03 6,8E-04 1,9E-04 5,9E-05

GWP 100 YEARS [KG CO2-EQUIV.]

4,5E-01 4,5E-01 1,9E-01 3,2E-02 1,2E+00 1,3E+00 5,4E-03 1,2E+00 5,9E-01 4,9E-03 7,3E-02 6,5E-01 8,9E-03

HTP INF. [KG DCB-EQUIV.]

2,0E-02 2,2E-02 1,3E-02 7,9E-02 4,2E-02 4,0E-01 3,4E-04 2,8E-02 3,2E-03 7,6E-03 5,2E-02 1,6E-02 3,9E-03

ODP, STEADY STATE [KG R11-EQUIV.]

2,0E-11 2,3E-12 2,1E-13 1,4E-13 1,1E-13 5,3E-14 1,2E-14 4,2E-14 1,0E-14 6,9E-12 1,6E-12 6,0E-13 7,3E-14

POCP [KG ETHENE-EQUIV.]

8,1E-05 1,2E-04 1,4E-04 2,3E-04 1,9E-04 4,9E-04 6,8E-07 1,6E-04 9,6E-05 2,6E-06 2,6E-05 4,4E-05 9,9E-07

GLOBAL ENVIRONMENTAL INDICATORS Global indicators (3): Global warming (GWP, kg CO2-eq.), ozone depletion (ODP, kg R11 -eq) and

abiotic depletion (ADP, kg Antimony (Sb) -eq.)

Figure 1: Global warming for the production of 1kWh of electricity for different technologies in

Slovenia

Figure 1 shows that GWPs have the highest technologies based on the use of fossil fuels: black coal, oil

and lignite. The slightly lower value of the indicator is for natural gas. In the case of the use of wastes

for the production of electricity, it can be seen that in the case of global warming, it is technology that

has an impact higher than natural gas. The results are expected.

Abiotic depletion (ADP) for the production of 1kWh of electricity for different technologies in

Slovenia

0,445 0,450

0,190

0,032

1,160

1,250

0,005

1,248

0,585

0,0050,073

0,649

0,0090,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

CML2001 - Jan. 2016, Global Warming Potential (GWP 100 years) [kg CO2-Equiv.]

1,78E-07 1,60E-07

7,86E-07

7,52E-08 6,02E-09 8,13E-082,07E-07

3,31E-09 5,18E-08 3,35E-08

4,04E-06

6,67E-08

4,49E-07

0,00E+00

5,00E-07

1,00E-06

1,50E-06

2,00E-06

2,50E-06

3,00E-06

3,50E-06

4,00E-06

4,50E-06

CML2001 - Jan. 2016, Abiotic Depletion (ADP elements) [kg Sb-Equiv.]

In the case of abiotic depletion (ADP), the highest environmental impact have RES or. renewable

energy sources. The highest impact can be seen is solar electricity production, followed by a 4x lower

impact for biogas, followed by wind energy and hydropower. Explain why (background) and, above

all, why the wind!

Biogas: The depletion of elements for Plants 1–4 is mainly due to the cultivation of maize and is

associated with the materials used for agricultural machinery (steel). For Plant 5, on the other hand,

the major contributors are construction materials for the AD and CHP plants

(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786543/ )

PV: Solar PV in particular has a very high ADP-E, primarily due to depletion of silver and tellurium

during the manufacture of the metallisation pastes required for silicon cell production (although

copper and silver components in capacitors also contribute to this impact).

(http://www.sciencedirect.com/science/article/pii/S0306261914008745 ).

Wind: 3.1.1. Abiotic depletion potential (ADP elements and fossil)

The wind turbine depletes 5.39 mg Sb eq./kWh of abiotic elements (Fig. 5). As shown in Fig. 6, 99% of

this is incurred in the manufacturing stage due to the depletion of molybdenum used for steel

production. The depletion of fossil fuels is estimated at 1.15 MJ/kWh. This is again in the

manufacturing stage which contributes 85.5% to the total consumption of fossil fuels due to energy

used for steel production ( http://www.sciencedirect.com/science/article/pii/S0360544213005355 ).

Figure 3: Ozone layer depletion (ODP) for the production of 1kWh of electricity for different

technologies in Slovenia

In the case of ozone layer depletion (ODP), the EU28 mix stick out of results, and among the Slovenian

technologies the highest rated is nuclear energy, followed by photovoltaics and electricity generation

from wastes. What is in the nuclear and PV's that puts them in such a position as regards ODP?

1,97E-11

2,26E-12

2,09E-13 1,39E-13 1,07E-13 5,34E-14 1,18E-14 4,17E-14 1,04E-14

6,92E-12

1,59E-126,02E-13 7,30E-14

0,00E+00

5,00E-12

1,00E-11

1,50E-11

2,00E-11

2,50E-11

CML2001 - Jan. 2016, Ozone Layer Depletion Potential (ODP, steady state) [kg R11-Equiv.]

Nuclear: 2.3.4. Ozone layer depletion

Ozone layer depletion refers to the thinning of the stratospheric ozone layer by chlorofluorocarbons

(CFCs), which results in increased transmission of UVB radiation to the earth’s surface. Despite the ban

of CFCs under the Montreal Protocol [114] some ozone depleting substances are still manufactured in

various non-signatory countries for use in signatory countries. As such, ozone depletion is still a

relevant issue. As shown in Fig. 4, nuclear power emits around 0.55 μg CFC-11 equiv/kWh, most of

which is normally attributable to mining and milling, although the figures can also vary widely

depending on the enrichment technology used.

(http://www.sciencedirect.com/science/article/pii/S036054421100541X ).

PV: for solar PV (3.6–25.2 μg). In the PV life cycle this impact is mainly due to the manufacture of

tetrafluoroethylene, the polymer of which (Teflon) is often used in solar cell encapsulation

(http://www.sciencedirect.com/science/article/pii/S0306261914008745 ).

REGIONAL IMPACT INDICATORS

Regional indicators (2): Acidification (AP, kg SO2 -eq.), Fresh water eco toxicity (FAETP Inf., kg DCB-eq.)

Figure 4: Acidification of the environment (AP) for the production of 1 kWh of electricity for different

technologies in Slovenia

As regards acidification of the environment, the greatest negative impact is the generation of

electricity from oil, lignite and coal. Interestingly, the large AP also has electricity production from

biogas and biomass. Explain why!

Figure 5: Freshwater Eco Toxicity (FAETP) for the production of 1 kWh of electricity for different

technologies in Slovenia

In the case of eco-toxicity of fresh water, the production of electricity from heavy fuel oil is

considerably high, and it differs from others by 10 times the value.

0,0013

0,0022

0,0041

0,00240,0019

0,0098

0,0000

0,0026

0,00040,0000 0,0003

0,0007

0,00000,0000

0,0020

0,0040

0,0060

0,0080

0,0100

0,0120

CML2001 - Jan. 2016, Acidification Potential (AP) [kg SO2-Equiv.]

0,00089 0,00076 0,001230,00203

0,00062

0,01920

0,00000 0,00050 0,000290,00147

0,00068 0,00019 0,000060,00000

0,00500

0,01000

0,01500

0,02000

0,02500

CML2001 - Jan. 2016, Freshwater Aquatic Ecotoxicity Pot. (FAETP inf.) [kg DCB-Equiv.]

As shown in Fig. 6a, the BAU scenario has the highest FAETP emitting 6.57 Mt of dichlorobenzene (DCB)

eq./yr, mainly owing to heavy metals from oil (contributing 65%) and coal power plants(24%). (13)

Environmental implications of decarbonising electricity suply in large economies:

The case of Mexico. Available from:

https://www.researchgate.net/publication/263201474_Environmental_implications_of_decarbonisi

ng_electricity_suply_in_large_economies_The_case_of_Mexico [accessed Sep 13, 2017].

Nuclear: 3.5.4. Eco and human toxicity potentials

Some chemicals releases can be toxic for human and other living species in the ecosystem. Calculations on a real system are more than complex. To ease this calculation, we have considered that liquid effluents were all released in freshwater. This simplification leads to an overestimation of the impact since this impact would be lower in sea water because of the dilution effect. They are given in mg 1,4-dichloro-benzene equivalent/kWhe. Clearly, mining is the only contributor with more than 99% of the potential impact both for the eco and the human toxicity. Vanadium is the main contributor to the eco-toxicity potential (80%), followed by molybdenum (10%) and uranium (only 2.5%). Molybdenum is the main contributor to the human toxicity potential (63%), followed by selenium (17%), vanadium (16%), NOx (1.9%) and uranium (only 1.6%). In these two indicators, the potential impact is highly oriented by the conversion factors into 1,4-DCB (1,4-dichloro-benzene). Indeed, the high contribution of selenium to the human toxicity potential, which is however present at a very low amount, is explained by a very high conversion factor of 56,000, to be compared with a factor of only 12 for lead [26].

http://www.sciencedirect.com/science/article/pii/S0360544214002035

LOCAL ENVIRONMENTAL INDICATORS

Local indicators: Human and environmental toxicity (HTP / AETP / TETP), Eutrophication (EP, kg PO4-

ekv), Photochemical ozone creation (POPC, kg Ethene -eq.)

Figure 6: Eutrophication potential (EP) for the production of 1 kWh of electricity for different

technologies in Slovenia

The largest eutrophication potential is present in the case of biogas, almost half the EP of biomas is in

the case of solid biomass, followed by technologies based on oil, coal and lignite. The non-negligible

EP also has the technology of extracting electricity from wastes.

Figure 7: Human Toxicity (HT) for the production of 1 kWh of electricity for different technologies in

Slovenia

In the case of human toxicity, the production of electricity in the case of heavy fuel oil is very negative.

Then they are at roughly the same level of biomass, black coal and photovoltaics. To explain!

0,00012 0,00013

0,00091

0,00050

0,00026

0,00032

0,00000

0,00029

0,000050,00001 0,00002

0,00015

0,000000,00000

0,00010

0,00020

0,00030

0,00040

0,00050

0,00060

0,00070

0,00080

0,00090

0,00100

CML2001 - Jan. 2016, Eutrophication Potential (EP) [kg Phosphate-Equiv.]

0,0203 0,0220 0,0129

0,0789

0,0421

0,3970

0,0003

0,0282

0,0032 0,0076

0,0520

0,01640,0039

0,0000

0,0500

0,1000

0,1500

0,2000

0,2500

0,3000

0,3500

0,4000

0,4500

CML2001 - Jan. 2016, Human Toxicity Potential (HTP inf.) [kg DCB-Equiv.]

Slika 8: Nastanek poletnega smoga (POCP) za proizvodnjo 1kWh električne energije za različne

tehnologije v Sloveniji

In the case of summer smog (POCP), the production of heavy fuel oil is most influential, while in the

case of biomass, coal, lignite and biogas, about half is lower. Why biomass, biogas so high?

8,10E-051,16E-04

1,40E-04

2,25E-04

1,86E-04

4,89E-04

6,84E-07

1,58E-04

9,57E-05

2,56E-062,61E-05

4,39E-05

9,89E-070,00E+00

1,00E-04

2,00E-04

3,00E-04

4,00E-04

5,00E-04

6,00E-04

CML2001 - Jan. 2016, Photochem. Ozone Creation Potential (POCP) [kg Ethene-Equiv.]