primary energy demand of renewable energy carriers - part 1
TRANSCRIPT
Primary Energy Demand of Renewable Energy Carriers – Part 1:
Methodology and
Examples
Alexander Stoffregen
Dr. Oliver Schuller
28.05.2014
Agenda
2
Methodology and Examples – Part 1
• Introduction
• Primary energy – Definitions
• Primary energy – Accounting methods for electricity / steam
• Application of accounting methods in practice
• Conclusions
Policy Implications – Part 2
June 12, 2014, 15:00 by Andreas Hermelink, Ecofys
28.05.2014
Introduction
3
• Are renewable energy sources included in the primary energy consumption?
• What is the impact of an increasing renewable share in electricity generation?
Primary energy consumption of the
EU and 2020 target (Mtoe)
Primary energy accounting – does it matter?
Source: EC 20110
500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
2000 2010 2020 2030 2040 2050
Solar
Wind
Hydro
Biomass
Oil
Natural gas
Coal
Nuclear
EU net electricity generation by fuel
(TWh)
28.05.2014 4
Introduction
Efficiency of photovoltaic panels ~10-20%
• If 5-10 MJ of primary energy are accounted to
produce 1 MJ of electricity from solar power,
� the primary energy consumption would go
up with an increasing share of solar power.
• If renewable energy sources are excluded in the
primary energy consumption statistics,
� primary energy consumption might go down
without any efficiency measure.
28.05.2014 5
Primary energy – Definitions
Definition of primary energy
“The energy that is embodied in resources as they exist in nature: the
chemical energy embodied in fossil fuels or biomass, the potential
energy of a water reservoir, the electromagnetic energy of solar radiation
and the energy released in nuclear reactions” (Nakicenovic 1996)
28.05.2014 6
Primary energy – Definitions
Calculation of Primary Energy Factors (PEF) for electricity supply from combustible energy sources:
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� �� ������ reciprocal of thermal power plant efficiency
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���� !����,�
CF f = calorific value of a fuel
Input f, t = input of fuel per operation time
Output t = output of electricity or heat per operation time
28.05.2014 7
Primary energy – Definitions
Calculation of Primary Energy Factors (PEF) for electricity supply from non-combustible energy sources:
��� ��� ��
� �� ��
electricity output
measured?
28.05.2014 8
Primary energy – Definitions
No. Option Type of primary energy
1 PEF for electricity from non-combustible
renewables (e.g. hydro, solar, wind) = 0
n.a.
2 Different accounting methods are used to
determine the primary energy input/primary
energy equivalents
Accounting for total
primary energy
3 Only non-renewable primary energy is
considered, i.e. infrastructure for renewables (e.g.
hydropower station, solar panels etc.) and nuclear
fuel supply/use
Consideration of
non-renewable primary
energy only.
4 Combination of 2 & 3 but split up of primary
energy into renewable and non-renewable
Split into renewable and
non-renewable primary
energy
Options to account primary energy for electricity/heat from non-combustible energy sources
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Primary energy – Definitions
Overview of options & methods to account for primary energy
Option 2
• Direct equivalence method
• Physical energy content method
• Substitution method
Option 1
• No accounting method required � primary energy always zero
Option 3
• No accounting method required � renewable primary energy excluded, i.e. non-renewable primary energy only
Option 4
• Technical conversion efficiencies method
• Physical energy content method (or similar concepts)
28.05.2014 10
Primary energy - Accounting methods for electricity / steam
Direct equivalent method
Definition:
Primary energy equivalence (or conversion efficiency) of 100% between
primary energy from non-combustible sources (renewables & nuclear)
and electricity/heat
Example:
Appliance:
e.g. energy statistics of the UN
1 MJ
primary energy
1MJ
electricity
28.05.2014 11
Primary energy - Accounting methods for electricity / steam
Physical energy content method
Definition:
„Primary energy should be the first energy from downstream in the production
process for which multiple energy uses are practical“ (IEA 2004)
Examples (1):
Solar thermal (electricity or steam/thermal energy production)
generation
of heat
1 MJ electricity
1 MJ steam/thermal
energy2 MJ
3 MJ
28.05.2014 12
Primary energy - Accounting methods for electricity / steam
Physical energy content method
Examples (2):
For wind, hydro, and photovoltaic power, electricity is the first energy with
“multiple energy uses” � 1 MJ primary energy = 1 MJ electricity
Appliance:
Energy statistics of IEA, Eurostat, OECD
28.05.2014 13
Primary energy - Accounting methods for electricity / steam
Substitution method
Definition:
Use of technical conversion efficiencies of the fossil fuels that were substituted
by the electricity from renewable, non-combustible energies or that would be
required to replace the electricity (Grubler 2012)
Examples:
Average efficiency of fossil power plants (coal, natural gas, fuel oil) = 40%
� 2.5 MJ primary energy e.g. from wind / hydro = 1 MJ electricity
Appliance:
e.g. Energy statistics of U.S. Energy Information Administration (EIA)
28.05.2014 14
Primary energy - Accounting methods for electricity / steam
Technical conversion efficiencies
Definition:
Technical conversion efficiency between energy source and generated
electricity or heat is used to calculate the primary energy input
Examples:
Conversion efficiency of hydro power ≈ 85% (electricity output/potential energy
of water) � 1.2 MJ primary energy � 1 MJ electricity
Appliance:
e.g. Often used in environmental assessments, such as life cycle
assessment (LCA) (usually not in energy statistics)
28.05.2014 15
Application of accounting methods in practice
Primary energy equivalents & conversion efficiencies
Energy source Direct equivalent
method
Physical energy content
method
Substitution method1
Technicalconversion efficiency2
Hydro 100% 100% 39.7% 85%
Wind 100% 100% 39.7% 40%
Solar - photovoltaic 100% 100% 39.7% 13.4%
Solar - thermal electric 100% 33% 39.7% 12.4%
Geothermal 100% 10% 39.7% 22.4%
Biomass (solid) 28.6%3
1 Substitution via average European fossil power plant, based on IEA data (reference year 2010)2 Conversion efficiencies taken from PE INTERNATIONAL’s “GaBi LCA databases 2012”3 Average European gross efficiency for biomass powered electricity plants, based on IEA data (reference year 2010)
28.05.2014 16
Application of accounting methods in practice
Primary energy factors using different methodologies
1 Primary energy factors for infrastructure/fuel supply (PE INTERNATIONAL’s “GaBi LCA databases 2012”), 2 Heath 2012
MJprimary energy / MJelectricityHydro Solar (thermal
electric)Geo-
thermalType of primary energy
Option 1 Zero equivalent n.a.
Option 2 2a - Direct equivalent 1.0 1.0 1.0 total
2b - Physical energy content 1.0 3.0 10 total
2c - Substitution 2.5 2.5 2.5 total
Option 3 Non-renewable primary energy only
0.00351 0.112 0.00481 non-renewable
Option 4 4a – Technical conversion efficiency
0.00351 0.112 0.00481 non-renewable
1.2 8.1 4.5 renewable
4b – Physical energy content 0.00351 0.112 0.00481 non-renewable
1.0 3.0 10 renewable
28.05.2014 17
Application of accounting methods in practice
Primary energy factors for country specific grid mixes
Natural gas
4%Biomass
0,4%
Hydro
95%
Wind
1%
Norway
Coal
88%
Natural
gas
3%
Fuel oil
2%Biomass
4%
Hydro
2% Wind
1%
Nuclear
20%
Coal
9%
Natural gas
32%
Fuel oil
5%
Biomass
2%
Hydro
15%
Wind
15%
Solar -
photovoltaic
2%
SpainPoland
Used energy sources for electricity generation in selected countries (IEA data, reference year 2010)
28.05.2014 18
Application of accounting methods in practice
Primary energy factors for country specific grid mixes
MJprimary energy / MJelectricityGrid mix Norway
Grid mix Spain
Grid mix Poland
Type of primary energy
Option 1 Zero equivalent n.a.
Option 2 2a - Direct equivalent 1.2 1.7 2.9 total
2b - Physical energy content 1.2 2.1 2.9 total
2c - Substitution 1.9 2.5 3.0 total
Option 3 Non-renewable primary energy only1
0.086 2.0 3.0 non-renewable
Option 4 4a – Technical conversion efficiency1
0.086 2.0 3.0 non-renewable
1.3 0.83 0.21 renewable
4b – Physical energy content 0.0861 2.01 3.01 non-renewable
1.1 0.35 0.19 renewable1 Primary energy factors for infrastructure / fuel supply (PE INTERNATIONAL’s “GaBi LCA databases 2012”)
Primary energy factors for imported electricity in energy statistics (Option 2) = 1.0 !
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Conclusions (1/2)
• Different options & methods to account for primary energy consumption of renewable energy carriers:
• Consideration of the following options:
• Total primary energy
• Non-renewable primary energy
• Split up into non-renewable and renewable primary energy
• Methods to calculate primary energy consumption:
• Direct equivalent method
• Physical energy content method
• Substitution method
• Technical conversion efficiency method
28.05.2014 20
Conclusions (2/2)
• Depending on methodology, primary energy factors may distinctly vary for the same renewable energy source.
• Split up into renewable and non-renewable primary energy could help to interpret energy consumption over time:
• Finite energy sources are not added with infinite ones
• Both indicators can be determined and improved independently
• Primary energy factors, energy statistics or targets have to be analysed and compared with care:
• Same methodology?
• Impact of increasing renewables and electricity imports?
• Is primary energy a helpful indicator for a target or analysis?
28.05.2014 21
Outlook
Policy Implications – Part 2June 12, 2014, 15:00 by Andreas Hermelink
The webinar will present to what extent different definitions of primary energy factors for renewables have implications on the three energy policy fields:
1. EU Directives– Energy Performance of Buildings Directive (EPBD), Energy
Efficiency Directive (EED), Renewable Energy Directive (RED);
2. the influence on the target setting in overarching EU communications;
3. the influence on energy accounting (statistics).
