MOOC Zero-Energy Design
MOOC Zero-Energy Design Course Reader Module 1
1. Energy Consumption
Current Trends:
Energy consumption is growing strongly worldwide; total consumption has more than tripled in the last 45 years.
Significant increases noted in countries such as China, India, and Brazil.
A slight decrease in total consumption was observed in 2009 due to the economic crisis.
Expectations indicate that global energy consumption and CO2 emissions will continue to rise in the coming decades, primarily driven by energy policy and supply security.
1.1 Societal Aspects of Energy Consumption
Dependence on Energy:
Economies of industrialized nations heavily reliant on affordable and immediately available energy.
Current energy sources primarily fossil fuels: oil, natural gas, and coal.
Environmental and Political Implications:
The use of fossil fuels increases environmental pressure and introduces uncertainties concerning energy supply.
1.1.1 Security of Supply
Definition:
"Security of supply" refers to the assurance regarding the availability of sufficient energy sources in present and future contexts.
Global Perspective:
Current energy supply challenges stem from political and economic instability where oil and gas wells are located.
EU’s forecast:
Limited oil and gas reserves.
Expected import dependency:
Future estimates predict reliance on OPEC and Russia for 95% of oil imports and 80% of gas imports by around 2030.
Reduction in energy demand could diminish the importance of security of supply.
1.1.2 Environmental Pressure and Energy Consumption
Consequences of Fossil and Nuclear Energy Use:
Produces local degradation and pollution, alongside global greenhouse gas emissions leading to climate change.
Key Emissions:
Emission of greenhouse gases, including CO2 and NOx, exacerbates local and global climate issues.
Deforestation further aggravates climate change.
Climate Change:
Recognized global issues due to increased greenhouse gas emissions.
The Paris Climate Agreement targets a limit of rising temperatures to 2°C above pre-industrial levels, ideally not exceeding 1.5°C.
Average temperature rose 1°C globally, with 1.7°C in the Netherlands over the last century.
Expected Consequences:
Rise of 1-2°C poses risks of flooding, extreme weather patterns including dry summers, and changes in river discharge.
1.2 Development of Energy Consumption
1.2.1 World Energy Consumption
Growth Patterns:
Tripled energy consumption over the last 45 years predominantly by North America, Europe, and Asia.
Asia has seen an extreme increase since 2000, while Europe and North America's energy demand has stabilized.
Figures Representing Consumption:
Figure 1.2: World energy consumption per continent [3].
Figure 1.3: Primary world energy consumption per energy carrier, with fossil fuels dominating the energy mix, while renewables show rapid growth.
Future Consumption Scenarios
Analyzing potential developments in energy consumption via scenarios considering:
International interdependence (globalization vs. regionalization).
Efficiency versus solidarity in energy deployment.
IAE Scenarios:
Current energy policy reference scenario projected continuing reliance on fossil fuels until 2030, with eventual possible reduction influenced by energy-saving practices.
The necessity for peak fossil fuel use to approach zero by 2050 in alignment with the Paris Climate Agreement.
2. Energy Units and Conversion Factors
2.1 Units for Energy and Power
Energy Measurement:
Basic SI Unit: Joule (J) is the fundamental unit of energy.
Power Measurement: Power is defined as the energy consumed per unit time:
Unit: Joule per second (J/s) or Watt (W).
Energy Calculation:
Example Conversion: 1 kWh = 3.6 MJ (1000 W for 3600 seconds).
Energy Units Table:
SI Units
J (joules)
kJ (kilojoules)
MJ (megajoules)
GJ (gigajoules)
etc.
Non-SI Units:
kWh (kilowatt-hour): 3.6 MJ
MWh (megawatt-hour): 3.6 GJ
2.2 Primary & Secondary Energy
Definition of Primary Energy:
Primary energy consists of resources derived directly from nature, including:
Fossil Fuels (Coal, Oil, Gas), Nuclear, Geothermal, Solar, Hydro, Biofuel, Wave, and Tidal Energy.
Distinction: Renewable (sustainable) vs. Non-renewable (limited supply).
Transition Importance:
A shift to renewable energy sources is essential to prevent resource depletion and minimize CO2 emissions.
CO2 Emission Reduction:
Producing 1 kWh via sustainable sources reduces CO2 emissions by 0.62 kg versus conventional methods.
2.3 Energy Carriers and Conversion Factors
Energy Carrier Definition:
Secondary energy results from transformed energy when primary resources do not suffice.
Example: Crude oil must be refined before use in vehicles or boilers.
Generation Efficiency:
Efficiency rates in power generation vary:
Gas turbine: ~40% efficient.
Combined cycle gas turbine: up to 60% efficiency.
Wind turbine reaches theoretical limits up to 59%.
Conversion Factors Table:
For various fuels, showing energy content per unit.
Example Calculation
A Dutch household uses:
1,470 m³ of natural gas and 3,000 kWh of electricity yearly.
Calculating Primary Energy Use:
Total: