Energy Management: 2014/2015 Primary, Final & Useful Energies Sankey Diagrams 1 st and 2 nd law efficiencies Historical Energy Use Class # 3 Prof. Tânia Sousa

Energy Units and Scales How much energy should we ingest daily? How much energy do you spend per hour using an electric heater?

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales Activities (kJ) IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales Activities (MJ-GJ or kWh=3.6MJ) IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales Activities (GJ-TJ or toe=41.87GJ) IAASA – Global Energy Assessment 2012

Energy Units and Scales Activities (GJ-TJ or toe=41.87GJ) In early agricultural societies –10-20 GJ/capita/year –2/3 for food and feed –1/3 for cooking, heating and early industrial activities In UK in the mid-19 th century –100 GJ/capita/year In Portugal in 2010 –108 GJ/capita/year

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Energy Units and Scales IAASA – Global Energy Assessment 2012

Forms of Energy - Primary energy

Forms of Energy - Final energy

Forms of Energy – Useful Energy

Forms of Energy Primary energy – embodied in resources as it is found in nature (coal, oil, natural gas in the ground) Final energy – sold to final consumers such as households or firms (electricity, diesel, processed natural gas) Useful energy – in the form that is used: light, heat, cooling and mechanical power (stationary or transport) Productive energy – the fraction of useful energy that we actually use

From Primary Energy to Energy Services

IAASA - Global Energy Assessment 2012 Energy Supply energy flows driven by resource availability and conversion technologies

From Primary Energy to Energy Services IAASA - Global Energy Assessment 2012 The energy supply sector dealing with primary energy is referred as “upstream” activities

From Primary Energy to Energy Services IAASA - Global Energy Assessment 2012 The energy supply sector dealing with secondary energy is referred as “downstream” activities

From Primary Energy to Energy Services IAASA - Global Energy Assessment 2012 Energy Demand Energy system is service driven

From Primary Energy to Energy Services IAASA - Global Energy Assessment 2012 Quality and cost of energy services

Energetic Balance Where are the primary and final energies in the energetic balance? BALANÇO ENERGÉTICO tep Total de CarvãoTotal de Petróleo Gás Natural (*) Gases o Outros Derivados Total de Eectricidade Calor Resíduos Industriais Renováveis Sem Hídrica TOTAL GERAL = 1 a 322= = 24 a 2936 = 31 a = 39 a 45 47= IMPORTAÇÕES PRODUÇÃO DOMÉSTICA VARIAÇÃO DE "STOCKS" SAÍDAS CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA CONSUMO DO SECTOR ENERGÉTICO CONSUMO COMO MATÉRIA PRIMA DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRACTIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS

Energetic Balance Where are the primary and final energies in the energetic balance? BALANÇO ENERGÉTICO tep Total de CarvãoTotal de Petróleo Gás Natural (*) Gases o Outros Derivados Total de Eectricidade Calor Resíduos Industriais Renováveis Sem Hídrica TOTAL GERAL = 1 a 322= = 24 a 2936 = 31 a = 39 a 45 47= IMPORTAÇÕES PRODUÇÃO DOMÉSTICA VARIAÇÃO DE "STOCKS" SAÍDAS CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA CONSUMO DO SECTOR ENERGÉTICO CONSUMO COMO MATÉRIA PRIMA DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRACTIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS

Energetic Balance Where is the useful energy in the energetic balance? BALANÇO ENERGÉTICO tep Total de CarvãoTotal de Petróleo Gás Natural (*) Gases o Outros Derivados Total de Eectricidade Calor Resíduos Industriais Renováveis Sem Hídrica TOTAL GERAL = 1 a 322= = 24 a 2936 = 31 a = 39 a 45 47= IMPORTAÇÕES PRODUÇÃO DOMÉSTICA VARIAÇÃO DE "STOCKS" SAÍDAS CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA CONSUMO DO SECTOR ENERGÉTICO CONSUMO COMO MATÉRIA PRIMA DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRACTIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS

Energetic Balance How do you go from final to useful energy for household electricity consumption? BALANÇO ENERGÉTICO tep Total de CarvãoTotal de Petróleo Gás Natural (*) Gases o Outros Derivados Total de Eectricidade Calor Resíduos Industriais Renováveis Sem Hídrica TOTAL GERAL = 1 a 322= = 24 a 2936 = 31 a = 39 a 45 47= IMPORTAÇÕES PRODUÇÃO DOMÉSTICA VARIAÇÃO DE "STOCKS" SAÍDAS CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA CONSUMO DO SECTOR ENERGÉTICO CONSUMO COMO MATÉRIA PRIMA DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRACTIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS

Useful Energy How do you go from final to useful energy for household electricity consumption? Electrical resistance100% Electrical motor90% Fluorescent lamp50% Refrigerator200% Heat pump250%

Sankey diagrams Schematic representation of the energy flow Miguel Águas (2009)

Sankey Diagram for Portugal for 2010 BALANÇO ENERGÉTICO tep Total de Carvão Total de Petróleo Gás Natural Total de Eletricidade Renováveis Sem Eletricidade TOTAL GERAL = 1 a 322= = 31 a 3546 = 39 a 45 47= CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA Produtos de Petróleo Eletricidade Cogeração CONSUMO DO SECTOR ENERGÉTICO Consumo Próprio da Refinação Perdas da Refinação Centrais Eléctricas Bombagem Hidroeléctrica Perdas de Transporte e Distribuição DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRATIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS

Sankey diagram for Portugal 2010

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 IAASA – Global Energy Assessment 2012

World Sankey Diagram in 2005 Overall 1 st law efficiency in converting primary to final energy? IAASA – Global Energy Assessment 2012 US – 94 EJ Portugal – 1.1 EJ ? ?

World Sankey Diagram in 2005 Overall 1 st law efficiency in converting primary to final energy? 66% IAASA – Global Energy Assessment 2012 US – 94 EJ Portugal – 1.1 EJ ? ?

World Sankey Diagram in 2005 Overall 1 st law efficiency in converting primary to useful energy? IAASA – Global Energy Assessment 2012 US – 94 EJ Portugal – 1.1 EJ ? ?

World Sankey Diagram in 2005 Overall 1 st law efficiency in converting primary to useful energy? 34% IAASA – Global Energy Assessment 2012 US – 94 EJ Portugal – 1.1 EJ ? ?

Typical values of 1 st law efficiencies 1 st Law efficiencies from primary to final energy 1 st Law efficiencies from final to useful energy

Sankey Diagram for an Energy Service Example?

Sankey Diagram for an Energy Service Example?

Sankey Diagram for an Energy Service Schematic representation of the energy flow (natural gas electricity light reading) What is the aggregate efficiency? 20% 50%

Sankey Diagram for an Energy Service Schematic representation of the energy flow (natural gas electricity light reading) What is the aggregate efficiency? 20% 50%

What is the 1 st Law efficiency in a heat pump? Are there 1 st law efficiencies > 1?

What is the 1 st Law efficiency in a heat pump? Typical values of  between 3 – 5 What is the Sankey diagram like? Are there 1 st law efficiencies > 1?

What is the 1 st Law efficiency in a heat pump? Typical values of  between 3 – 5 What is the Sankey diagram like? Are there 1 st law efficiencies > 1?

Sankey Diagram A coal thermal power plant has an efficiency of 40%. The combustion of coal releases 7000kcal/kg. The energy consumption associated with extraction, transport and grinding represent 500 kcal/kg. 1.Draw the Sankey Diagram

A coal thermal power plant has an efficiency of 40%. The combustion of coal releases 7000kcal/kg. The energy consumption associated with extraction, transport and grinding represent 500 kcal/kg. 1.Draw the Sankey Diagram 2.What is the overall efficiency? Sankey Diagram Coal Mine Coal at the Power Plant Electricity 40% 93% Coal at the coal mine Coal at the Power Plant Electricity at the Power Plant 7% 60% 1 Mcal = MJ 1 toe = MJ 1 MWh = 3600 MJ

A coal thermal power plant has an efficiency of 40%. The combustion of coal releases 7000kcal/kg. The energy consumption associated with extraction, transport and grinding represent 500 kcal/kg. 1.Draw the Sankey Diagram 2.What is the overall efficiency? 3.What is the coefficient of conversion between final and primary energy in MWh e /TOE? Sankey Diagram Coal Mine Coal at the Power Plant Electricity 40% 93% Coal at the coal mine Coal at the Power Plant Electricity at the Power Plant 7% 60% Eficiency = 2600/7000 = 37% 1 Mcal = MJ 1 toe = MJ 1 MWh = 3600 MJ

A coal thermal power plant has an efficiency of 40%. The combustion of coal releases 7000kcal/kg. The energy consumption associated with extraction, transport and grinding represent 500 kcal/kg. 1.Draw the Sankey Diagram 2.What is the overall efficiency? 3.What is the coefficient of conversion between final and primary energy in MWh e /TOE? Sankey Diagram Coal Mine Coal at the Power Plant Electricity 40% 93% 1 Mcal = MJ 1 toe = MJ 1 MWh = 3600 MJ

Conversion between F.E and P.E Conversion coefficients are efficiencies and not direct conversions –From coal (P.E) to electricity (F.E) –Direct conversion ??????????

Conversion between F.E and P.E Conversion coefficients are efficiencies and not direct conversions –From coal (P.E) to electricity (F.E) –Direct conversion

Conversion between F.E and P.E Conversion coefficients are efficiencies and not direct conversions –From coal (P.E) to electricity (F.E) –Direct conversion What about the conversion coefficient from natural gas to electricity?

Are first law efficiencies enough? Heating of a house can be done by one of the following methods: 1.Electrical heating using the Joule effect 2.Central heating 3.Heating using a heat pump

Are first law efficiencies enough? Heating of a house can be done by one of the following methods: 1.Electrical heating using the Joule effect 2.Central heating (burning natural gas in a furnace with a 90% efficiency) 3.Heating using a heat pump (COP=3). Suppose that electricity has a production efficiency of 45% and costs 0.12 euros per kWh, natural gas is transported with a 99% efficiency, and costs euros per kWh. a)Compare the alternatives in terms of primary energy, final energy and cost for 1 kWh of thermal energy. Draw the Sankey Diagrams

Are first law efficiencies enough? Heating of a house can be done by one of the following methods: 1.Electrical heating using the Joule effect 2.Central heating (burning natural gas in a furnace with a 90% efficiency) 3.Heating using a heat pump (COP=3). Suppose that electricity has a production efficiency of 45% and costs 0.12 euros per kWh, natural gas is transported with a 99% efficiency, and costs euros per kWh. a)Compare the alternatives in terms of primary energy, final energy and cost for 1 kWh of thermal energy. Draw the Sankey Diagrams Electrical ResistanceCentral HeatingHeat Pump Primary (kWh)1/0.45=2.22(1/0.90)/0.99=1.12(1/3)/0.45=0.74 Final (kWh)11/0.90=1.111/3=0.33 Useful (kWh)111 Cost (euros)1*0.12((1/0.9))* /3*0.12

Are first law efficiencies enough? Providing 1 kWh of heat at 30ºC to a building with an outside temperature of 4ºC First law efficiencies do not provide information on how much you can improve your efficiency Electrical Resistance Central Heating Heat Pump Ideal Heat Pump Final (kWh)11/0.901/31/12 Useful (kWh) 1111 First Law  100%90%300%1200%

Second law efficiencies Ratio between 1 st law real and best efficiencies Providing 1 kWh of heat at 30ºC to a building with an outside temperature of 4ºC Second law efficiencies provide information on how much you can improve your efficiency Electrical Resistance Central Heating Heat Pump Ideal Heat Pump Final (kWh)11/0.901/31/12 Useful (kWh)1111 First Law  100%90%300%1200% Second Law  8.3%7.5%25%100%

Typical values of 2 nd law efficiencies Overall 2 nd law efficiency in converting primary to final is 76% and primary to useful energy is 10% IAASA - Global Energy Assessment 2012

Second law efficiencies Second law efficiencies by providing information on how much you can improve your efficiency show where efforts should be made Rosen and Dincer, 1997

Population (lines) Primary energy use (bars) industrialized countries (white squares and bars) developing countries (gray triangles and bars) Energy use data includes estimates of noncommercial energy use Primary Energy Use Grubler, A. “Energy Transitions”

Population (lines) Primary energy use (bars) industrialized countries (white squares and bars) developing countries (gray triangles and bars) Energy use data includes estimates of noncommercial energy use Primary energy use increased more than 20-fold in 200 years Heterogeneity in per capita primary energy use: In industrialized countries population increased linearly while primary energy use increased exponentially until recently In developing countries energy use increased proportionally to population until recently Primary Energy Mix ? Primary Energy Use Grubler, A. “Energy Transitions”

Primary Energy Mix IAASA – Global Energy Assessment 2012

Grubler, A. “Energy Transitions” Primary Energy Mix Mostly biomass in 1850 Increasing diversification of energy vectors IAASA – Global Energy Assessment 2012

Grubler, A. “Energy Transitions” Primary Energy Mix

Primary Energy Mix Energy Transition: The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012)

Primary Energy Mix Energy Transition: The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) Energy Transition biomass to coal

Primary Energy Mix Energy Transition: The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) Energy Transition biomass to coal Energy Transition coal to oil

Primary Energy Mix Energy Transition: The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) Energy Transition biomass to coal Energy Transition coal to oil Stabilization

Energy Eras and Transitions Energy Transformations before industrial civilization:

Energy Eras and Transitions Energy Transformations before industrial civilization: –Solar radiation – food & feed, light and heat –Animate labor from humans and work animals (levers, inclined planes, pulleys) – mechanical work & transport –Kinetic energies of water & wind – mechanical work & transport –Biomass fuels (wood, charcoal, crop residues, dung) – residential & industrial heat and light

Energy Eras and Transitions Energy Transformations before industrial civilization: –Dominant in the western world until the 2 nd half of the 19 th century –Dominant for most of humankind until middlle of the 20 th century –Annual per capita primary energy consumption  20 GJ

Energy Eras and Transitions Energy Transformations that came with industrial civilization: –Fossil fuels – heat & mechanical work & transport (steam engines, internal combustion engines and steam turbines)

Energy Transitions An aggregated transition to other energy source(s) includes numerous services and sectors

Energy Transitions The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) 16 th century (tall narrow chimneys and suitable grates ) 17 th century (coal gets even cheaper)

Energy Transitions The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) 1709 (coke) 18 th century (efficiency improvments)

Energy Transitions The switch from an economic system dependent on one or a series of energy sources and technologies to another (Fouquet & Pearson, 2012) 1804 (1 st steam locomotive)

Why do energy transitions occur? Main Drivers/Catalyst for adoption of a new energy carrier: –Price of energy –Better/Different Service –Technological change and innovation –Efficiency improvments

Why do energy transitions occur? Main Drivers/Catalyst for adoption of a new energy carrier: –Price of energy –Better/Different Service –Technological change and innovation –Efficiency improvments –Environmental Impacts?

Decarbonization of Energy Systems Decreasing trend in CO 2 emitted per GJ from 1850 to : 108 GJ/capita/year 7600 kg CO 2 /capita/year

Decarbonization of Energy Systems Historically energy related biomass burning has not been carbon-neutral (maximum estimated value of 38%)

Decarbonization of Energy Systems Why a slight increasing trend in the last 10 years?

Power generation Despite an increasing contribution across two decades, the share of non-fossil generation has failed to keep pace with the growth in generation from fossil fuels. © OECD/IEA 2012 Electricity generation (TWh) Share of electricity (%) Share of coal-based electricity Share of non-fossil electricity Nuclear Hydro Non-hydro renewables IEA - Energy Technology Perspectives 2012

Final Energy from World final energy use by consumers. Solids (such as coal and biomass, brown), Liquids (such as oil, red) and fuels delivered via dedicated Grids (such as natural gas and electricity, green). Grubler, A. “Energy Transitions”

Final Energy from World final energy use by consumers. Solids (such as coal and biomass, brown), Liquids (such as oil, red) and fuels delivered via dedicated Grids (such as natural gas and electricity, green). “With rising incomes, consumers pay increasing attention to convenience and cleanliness, favoring liquids and grid-delivered energy forms” Grubler, A. “Energy Transitions”

Final Energy from World final energy use by consumers. Solids (such as coal and biomass, brown), Liquids (such as oil, red) and fuels delivered via dedicated Grids (such as natural gas and electricity, green). Developing countries OECD (squares) Grubler, A. “Energy Transitions”

Final Energy from World final energy use by consumers. Solids (such as coal and biomass, brown), Liquids (such as oil, red) and fuels delivered via dedicated Grids (such as natural gas and electricity, green). Heterogeneity in final energy quality Grubler, A. “Energy Transitions”

Final Energy per capita in 2010 Heterogeneity in Final Energy Use per capita: IAASA – Global Energy Assessment 2012

What is Final Energy used for? UK IAASA – Global Energy Assessment 2012

What is Final Energy used for? Regular expansion of energy services in 19 th –dominated by heat and transport High volatility due to political and economic events Moderated growth after 1950 –Decline in industrial energy services compensated by strong growth in transport Saturated at a level of 6 EJ or 100 GJ/capita What about energy services? IAASA – Global Energy Assessment 2012

From Final Energy to Energy Services UK IAASA – Global Energy Assessment 2012

UK Increasing efficiencies in converting final energy to energy services –Ranges between a factor of 5 for transportation and 600 for lighting From Final Energy to Energy Services IAASA – Global Energy Assessment 2012

UK Lower prices of energy services –Ranges between a factor of 10 for heating and 70 for lighting From Final Energy to Energy Services IAASA – Global Energy Assessment 2012

Energy Services 2005 Energy services cannot be expressed in common units Transport –13 km/day/per capita –1 ton 20 km/day/per capita Industry –9 ton/year/per capita (steel + fertilizers + construction materials + plastics … Buldings –Heating/cooling to 20m 2 /per capita Useful energy –minimizes distortions among different energy service categories, as it most closely measures the actual energy service provided.

World Sankey Diagram in 2005

Second law efficiencies provide information on the destruction of exergy What is exergy? Power = 0 WPower = 150 kW Δz = 0m Δz = 120m Second law efficiencies

Energy vs. Exergy 160ºC25ºC Potential Work = 34 MJ Potential Work = 1.8 MJ environment 20ºC Energy = 105 MJ Exergy = 34 MJ Exergy = 1.8 MJ