Energy Sources
Level 2: Intermediate
Let's go!
Introduction
Energy plays a fundamental role in shaping modern society, driving economic development, and ensuring technological progress. As global energy demand increases, the need for sustainable and efficient energy use becomes more urgent. This course offers an in depth exploration of energy sources, their production methods, and the complex relationship between energy consumption and environmental sustainability. You will explore theorethical background, reflection questions, and exapes to develop a critical understanding of energy sources, also challenges and solutions related to it. By the end of this course, you will be able to critically examine various energy sources, assessing their benefits and risks, economic viability, and environmental impact.
Start Course
Energy Sources Level 2: Intermediate
Objectives
Modules
Exercises
Evaluation
Objectives
What will you learn?
- Gain a deeper understanding of different energy sources, their efficiency, sustainability, and impact on society.
- Understand the role of energy efficiency in reducing consumption and emissions.
- Analyze energy trends, policy strategies and frameworks that influence the future of energy supply.
- Reflect on how small energy-saving actions can reduce energy bills.
Modules
Module 3: Fossil fuels and decarbonization pathways
Module 1: Introduction to the objectives
Module 2: What is energy and its sources?
Module 4: Renewable energy sources
Module 5: Energy transition and policies
Module 6: Conclusions
What is energy and its transformation
Energy is the capacity to perform work or cause change and is fundamental to all processes in nature and technology. From heating homes to running industrial machinery, energy is at the core of modern civilization. There are various forms of energy, including kinetic (motion), thermal (heat), electrical, chemical, nuclear, and radiant (light) energy. These forms can be converted into one another through different processes.
Energy transformation occurs in everyday life. For example, in a power plant, chemical energy from fuel is converted into thermal energy, which is then transformed into mechanical energy to drive turbines, eventually generating electricity. Understanding these transformations helps us optimize energy use, increase efficiency, and reduce waste in both daily activities and large-scale industrial applications.
Figure 1. Energy forms [1]
How does energy transformation impact your daily life? Can you think of an example where inefficient energy conversion leads to energy loss?
Energy Sources
Energy sources are categorized into non-renewable and renewable
Renewable energy sources are derived from natural processes that replenish themselves over time. These include solar, wind, hydropower, biomass, and geothermal energy. They offer long term sustainability but require technological advancements for efficient storage and distribution.✅ Environmentally friendly with lower carbon emissions.✅ Sustainable and does not deplete over time. ❌ Higher initial investment costs and infrastructure development required.❌ Dependent on external factors like weather conditions (e.g., solar and wind energy).
Non-renewable energy sources are finite resources that deplete over time, such as coal, oil, natural gas, and uranium for nuclear power. While they provide a high energy output and infrastructure stability, their continued use raises concerns about resource depletion and environmental impact.✅ Provides a stable and reliable energy supply.✅ Infrastructure is already well-developed in most countries.❌ Contributes to climate change and environmental pollution.❌ Finite resources that will eventually be depleted.
Figure 2. Energy sources [2]
Energy consumption globally and in the European Union
- Global trends: Fossil fuels still account for over 80% of total energy consumption, but renewables are growing rapidly, driven by falling costs, increased efficiency, and supportive government policies. The share of renewable energy in total consumption is expected to rise significantly.
- European Union’s Energy Shift: The EU has set ambitious climate targets. Countries are phasing out coal, expanding wind and solar capacity, and investing in hydrogen and energy storage technologies.
- Sectoral Consumption: The industrial sector remains the largest consumer, relying heavily on fossil fuels for manufacturing. The transportation sector is undergoing rapid electrification, with increasing adoption of electric vehicles and hydrogen fuel technologies. The residential sector is transitioning towards greater efficiency with smart appliances, heat pumps, and rooftop solar.
Figure 3. Energy consumption by its sources [3]
What factors influence a country's decision to rely more on renewable or non-renewable energy sources? How does geography, economy, and policy shape these choices?
Benefits:
Nuclear energy: benefits and risks
- Nuclear fuel contains much more energy per unit than fossil fuels, making it highly efficient in electricity generation;
- While not emission-free, nuclear plants produce almost no carbon dioxide during operation, contributing to climate change mitigation;
- Unlike solar and wind, which depend on weather conditions, nuclear power provide a stable and continuous energy.
Nuclear energy is generated through nuclear fission, where atomic nuclei are split to release a tremendous amount of heat. This heat is then used to produce steam, which drives turbines to generate electricity. Unlike fossil fuels, nuclear power does not produce direct carbon dioxide emissions, making it a low-carbon energy source. However, it is not classified as renewable because it depends on finite resources.
Risks:
- Building nuclear power plants is capital-intensive, requiring billions of dollars and long construction timelines;
- Spent nuclear fuel remains hazardous for thousands of years, requiring secure long-term storage solutions;
- Accidents like Chernobyl (1986) and Fukushima (2011) highlight concerns about radioactive contamination and the risks associated with malfunctions.
France generates over 70% of its electricity from nuclear power, reducing its reliance on fossil fuels. However, debates continue on whether nuclear should remain a key part of the energy transition or be replaced entirely by renewables.
Comparison of energy sources
Different energy sources vary in economic, availability, reliability, and environmental aspects
Table 1. Comparison of energy sources
Fossil fuels
Fossil fuels — coal, oil, and natural gas — are formed from the remains of ancient plants and animals that have been subjected to heat and pressure over millions of years. They are non-renewable, meaning they are long to form and are being consumed faster than they are replenished. Fossil fuels became the primary energy source due to their high energy density, reliability, and well-established infrastructure. These fuels have been the backbone of industrialization, providing energy for electricity, transportation, and manufacturing. They have powered economic growth for over a century and currently supply over 80% of the world's energy needs. Their affordability and existing supply chains make them difficult to phase out entirely in the short term.
Figure 4. Fossil fuels [4]
Coal, oil, natural gas
Natural gas
Oil
Coal
- Burned to generate electricity in power plants, also for industrial heating, steel production.
- Largest source of electricity worldwide.
- Coal has the highest carbon footprint, harmful due to air pollution, and mining.
- China, India, and the US are the largest consumers.
- Formed alongside oil and coal, primarily composed of methane (CH₄).
- Used for heating, electricity generation, and as an industrial fuel.
- Often transported via pipelines or liquefied (LNG) for international trade.
- Lower CO₂ emissions than coal and oil, but releases methane, a potent greenhouse gas.
- Naturally found in liquid form.
- Refined into gasoline, diesel, and other fuels for transportation and for petrochemicals and plastics in industry.
- The world consumes over 90 million barrels of oil per day.
- Emits CO₂ into atmosphere, creates risk of oil spills.
- Price is influenced by geopolitical events.
Which of these fossil fuels do you think will be the hardest to replace? Why?
Environmental impact and depletion
Main environmental issues
Resource depletion
Coal: Coal is the most abundant fossil fuel, but high-grade coal reserves are depleting in many regions. Estimated to last another 100-150 years, but extraction is declining due to environmental concerns.Oil: Oil is becoming more difficult to extract, requiring deep-sea drilling, tar sands extraction, and fracking. Global oil reserves could be depleted in the next 50 years based on current consumption rates.Natural gas: Estimated to last 50-60 years, but new reserves are occasionally discovered. However, reserves are finite, and extraction methods like hydraulic fracturing (fracking) have raised environmental concerns.
Greenhouse gas emissions: Burning fossil fuels releases large amounts of carbon dioxide (CO₂) and methane (CH₄), which contribute to global warming and climate change. The energy sector accounts for nearly 75% of global greenhouse gas emissions. Air pollution: Power plants, vehicles, and industry emit sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulate matter, leading to smog, acid rain, and respiratory diseases. Oil spills and habitat destruction: Offshore drilling and oil transportation accidents result in major environmental disasters, affecting marine life and coastal ecosystems.
The Deepwater Horizon oil spill (2010) released nearly 4.9 million barrels of crude oil into the Gulf of Mexico, causing severe damage to marine ecosystems, local fisheries, and coastal economies.
Pathways for decarbonization
Decarbonization aims to reduce carbon dioxide (CO₂) emissions from energy production and consumption.
3. Carbon capture and storage
1. Transition to renewable sources
- Capture CO₂ emissions from from fossil fuel combustion and either stores it underground or repurposes it for industrial use (steel and cement manufacturing).
- Shift from fossil fuels to solar, wind, hydropower, and geothermal energy.
- Expand grid storage solutions to balance intermittent renewable sources.
4. Development of electrification
2. Enhance energy efficiency
- Expand electric vehicle adoption and phase out internal combustion cars.
- Tranform industrial processes to electricity-based alternatives.
- Improving energy efficiency in transportation, buildings, and industry.
- Technologies for high-efficiency appliances, improved insulation, and industrial waste heat recovery help lower energy consumption.
How to reduce dependency on fossil fuels?
Reducing reliance on fossil fuels can lower energy costs and contribute to sustainability
- Switch to renewable energy providers ☀️
Choose electricity providers that use renewable energy sources. Install solar panels, solar water heaters, or small wind turbines if possible.
- Improve home energy efficiency 🏠
Using energy-efficient lighting, smart thermostats, and properly insulated homes reduces energy demand and fossil fuel consumption.
- Use low-carbon transportation options 🚲
Walk, bike, use of public transport or car-sharing services instead of driving short distances by car can cut personal fuel consumption and emissions
Figure 5. Energy transition [5]
Why did fossil fuels remain the dominant energy source for so long, and what are the key challenges in moving away from them?
Renewable energy sources
Definition of renewable energy
Why is renewable energy important?
- Reduces dependence on fossil fuels lowering emisions of carbon dioxide (CO₂) and methane (CH₄) which impact climate change.
- Provides long-term stability in energy supply and pricing.
- Creates new job opportunities in manufacturing, installation, and maintenance of clean energy sectors.
- Reduces air pollution and related health problems
- Renewable energy refers to energy derived from natural processes that replenish themselves continously. They are virtually inexhaustible on a human timescale. It include solar, wind, hydropower, biomass, and geothermal energy.
- Unlike fossil fuels, renewable sources does not run out and emits little to no greenhouse gas emissions.
Figure 6. Renewable energy sources [6]
'A transition to clean energy is about making an investment in our future' - Gloria Reuben
Solar energy
How solar energy works:Solar energy is harnessed using photovoltaic (PV) panels, which convert sunlight into electricity through the photoelectric effect. Alternatively, concentrated solar power (CSP) systems use mirrors to focus sunlight and generate heat, which drives turbines to produce electricity.Benefits:Abundant and widely available, solar panels can be installed on homes, businesses, and large-scale farms with low operational costs.Challenges:Solar panels generate power only when sunlight is available. Although prices have dropped significantly, installation and battery storage remain expensive for many households.
Video 1. How solar energy is converted into electricity [7]
Wind energy
How wind energy works:Wind turbines convert kinetic energy from the wind into mechanical energy, which is then converted into electricity by a generator. Offshore wind farms are increasingly used due to their higher wind speeds and energy potential.Benefits:A single modern wind turbine can power thousands of homes per year. Wind energy produces no direct emissions and requires little water compared to fossil fuel plants.Challenges: Wind speeds fluctuate, requiring storage solutions or grid balancing mechanisms. Some communities oppose wind farms due to their visual impact and noise levels.
Video 2. How wind energy is converted into electricity [8]
The Hornsea Wind Farm in the UK, one of the largest offshore wind farms, supplies electricity to over one million homes while reducing carbon emissions significantly.
Hydropower
How hydropower works:Hydropower uses the energy of moving water to turn turbines, which generate electricity. Run-of-river, reservoir-based, and tidal power are the three main types of hydropower.Benefits:Hydropower plants have lifespans exceeding 50 years and achieve efficiencies of over 90%. Unlike solar and wind, hydropower provides continuous energy generation.Challenges: Dams disrupt river ecosystems, fish migration, and sediment transport impacting biodiversity. Building large-scale hydroelectric plants requires significant infrastructure costs and long construction timelines.
Video 3. How hydropower works [9]
Geothermal energy
How geothermal energy works:Geothermal energy harnesses heat from beneath the Earth's crust by drilling wells into geothermal reservoirs to produce steam, which powers turbines to generate electricity. Direct use applications include district heating, industrial processes, and greenhouse farming.Benefits:Continuous, reliable power that can be used for both electricty and heating. Geothermal heat pumps can cut heating and cooling costs by up to 60% compared to fossil fuel systems.Challenges: Limited to regions with geothermal activity. Requires high initial investment for drilling and infrastructure.
Video 4. How geothermal energy works [10]
Iceland generates nearly 90% of its heating needs from geothermal energy, making it a global leader in utilizing this renewable source for sustainable development.
Biomass energy
Benefits:
- Biomass absorbs CO₂ during growth, offsetting emissions when burned.
- Converts waste into energy, reducing landfill use.
- Organic waste can be converted into usable energy instead of being discarded.
- Provides an alternative to fossil fuels for electricity, heating, and transport fuels.
- Biomass has lower energy density and efficiency compared to fossil fuels or advanced renewables like wind and solar.
Biomass energy is derived from organic materials such as wood, agricultural residues, animal waste, and dedicated energy crops. It can be burned directly for heat, converted into biofuels (e.g., ethanol, biodiesel), or processed into biogas for electricity generation. Most common forms of biomass are wood pellets, biogas, and biodiesel.
Challenges:
- Biomass combustion can release fine particulates and other air pollutants.
- Unsustainable harvesting can lead to deforestation.
- Growing energy crops may compete with food production, affecting food security.
- Requires larger amounts of biomass to produce the same energy output as coal or oil.
Which of renewable energy sources do you think has the most potential for global adoption?
Figure 7. Wood pellets [11]
Global and the European Union energy transition goals
Energy transition refers to the global shift from fossil fuel-based energy systems to renewable and low-carbon energy sources. This process involves changes in infrastructure, policies, and consumption patterns to reduce environmental impact and improve energy security.
Paris Agreement (2015) is global international agreement that sets global targets to limit temperature rise below 2°C.
Over 190 countries are committed to set national climate targets, phasing out coal, and investing in renewables.
European Union transition goals
By 2050:
- Achieve net-zero greenhouse gas emissions, effectively making the EU climate-neutral.
By 2030:
- To reach at least 55% reduction of greenhouse gas emissions compared to 1990 levels;
- Requires EU countries to meet at least 42.5% of energy needs from renewables.
2050
2030
1990
What are the biggest obstacles to achieving a full energy transition, and how can they be addressed?
Renewable energy in Lithuania, Greece, Italy, Bulgaria, and Austria energy mix
The share of renewable energy in the total energy mix varies significantly between countries due to differences in natural resources, policy frameworks, and investment priorities. Lithuania and Austria are leading in renewable energy adoption, with high shares of wind and hydropower, while Italy and Greece are rapidly expanding their solar energy capacity. Bulgaria has historically relied on coal, but its transition includes growing investments in wind and biomass energy. Still, a significant gap can be noticed between share in electricity and total energy consumption. While renewable sources contribute substantially to electricity production, their share in overall energy use remains lower due to continued reliance on fossil fuels in sectors like transportation and heating.
Figure 8. Renewable energy share in countries (2023) [12]
What factors influence the choice of energy source in different countries?
National energy strategies in Lithuania, Greece, Italy, Bulgaria, and Austria
Lithuania
Greece
Italy
- Major investments in offshore wind and solar power; aiming for 100% renewable electricity by 2050.
- Investing in energy storage solutions and offshore wind projects to balance intermittent renewables. Implementing smart grids to optimize energy distribution.
- Strong push for solar, offshore wind farms and hydrogen infrastructure; aiming for 55% renewables by 2030.
- The government has adopted a plan to reintroduce nuclear energy, aiming to secure energy sufficiency and decarbonize industries.
- Phasing out coal by 2028, increasing solar and wind capacity, and integrating energy storage solutions.
- Establishing a fund to facilitate the decarbonization of its tourism dependent islands also incentives for homeowners to install solar panels and heat pumps.
Bulgaria
Austria
- Gradual transition away from coal, increasing hydropower, and expanding solar energy production.
- Focusing on improving grid infrastructure and interconnectivity to enhance energy stability also modernizing district heating systems.
- Targeting 100% renewable electricity by 2030, investing in hydropower expansion, wind and solar power.
- Despite high renewable electricity generation, Austria remains heavily reliant on gas, highlighting the need for diversification in energy sources for heating.
Energy independence and geopolitics
Why is energy independence important?
Economic and social impacts of energy instability
Reduces dependency on external energy suppliers, making countries more resilient to geopolitical tensions. Ensures stable and secure energy supply, reducing risks of energy shortages and price shocks. Encourages national investments in renewable energy, fostering local industry growth and job creation.
Rising energy prices affect consumers and industries, increasing the cost of living and slowing economic growth.Energy poverty becomes a growing concern, as vulnerable populations struggle to afford electricity and heating. Disruptions in industrial production due to fuel shortages can lead to job losses and inflation.
Transitioning towards energy security
How wars affect energy prices?
Expanding renewable energy capacity reduces reliance on imported fossil fuels and stabilizes energy costs.Investing in energy storage and smart grids ensures more efficient distribution and resilience. Diversifying energy imports and building regional energy alliances enhance supply security.
The Russia-Ukraine war (2022) led to unprecedented spikes in natural gas prices in Europe, prompting urgent energy diversification measures. Conflicts in major oil and gas producing regions cause supply disruptions and price volatility. Past conflicts like the 1973 Oil Crisis showcased how geopolitical instability can cripple economies reliant on fossil fuel imports.
National strategies to increase energy independence
How countries are reducing dependence on fossil fuels import?
Expanding renewable energy capacity (solar, wind, hydropower). Governments provide subsidies, tax incentives, and funding to accelerate the transition to renewables.
Battery storage, hydrogen production, and smart grids are key to ensuring a stable supply of electricity from renewables.
Countries are seeking alternative energy suppliers i. e. invest in liquefied natural gas (LNG) terminals to reduce reliance on natural gas of a single country.
Lithuania: LNG terminal for gas diversification to eliminate dependence on Russian gas imports; heavy investment in wind energy.
Greece: Accelerating solar and wind energy projects; interconnection projects with other EU countries.
Italy: Increasing solar, wind, and hydrogen production, particularly in southern regions; interconnections with neighboring countries.
Bulgaria: Transitioning from coal to a mix of natural gas and renewables; modernizing its energy grid for better efficiency.
Austria: Strong focus on hydropower expansion; increasing cross-border energy cooperation with Germany and Switzerland for a more stable energy supply.
Which of these strategies seems the most effective? What challenges might these countries face in implementing them?
Conclusions
- While fossil fuels have powered economies for centuries, their environmental costs and resource depletion risks highlight the urgency of transitioning to sustainable alternatives.
- Solar, wind, hydropower, biomass, and geothermal energy are expanding rapidly, with innovations in energy storage, efficiency, and grid integration enhancing their viability.
- Strategies such as smart grids, electrification, energy storage, and carbon capture technologies are critical to reducing emissions and ensuring a sustainable energy transition.
- The global energy transition is influenced by geopolitical conflicts, supply chain vulnerabilities, and national policies. Countries are increasing domestic renewable energy production to enhance security and stability.
The transition to sustainable energy is not just a technological shift but a societal transformation. What actions can individuals, businesses, and policymakers take to accelerate this transition?
Exercises
Exercise 2 Household energy audit
Exercise 1 Compare energy source
Identify areas for energy savings in homes and understand the personal energy consumption patterns.
Evaluate different energy sources and recognize the factors influencing energy choices.
Exercise 1. Compare energy sources
- Select one fossil fuel source (e.g., coal, oil, natural gas) and one renewable energy source (e.g., solar, wind, hydropower).
- Fill a pros and cons table, analyzing the main factors.
Exercise 2. Household energy audit
questions to consider?
instructions
- Choose one room in your home (e.g., kitchen, living room, or bedroom) and list all the electrical appliances used there (e.g., lights, TV, heater, refrigerator).
- Estimate energy power: Identify which appliances are most powerful and research their approximate power usage (in watts or kWh).
- Identify energy saving opportunities: Consider changes such as using LED bulbs, adjusting to energy saving settings, or switching to energy efficient appliances.
- What are two immediate actions you can take to lower energy consumption in your home?
- How could adopting more energy efficient habits impact your electricity bills and environmental footprint?
- What challenges might prevent you from making these changes, and how could they be addressed?
Evaluation
Quiz
- This quiz consists of 7 multiple-choice questions related to energy sources, environmental impact, and energy transition.
- Choose the correct answer for each question (only one per question).
- The quiz helps reinforce key concepts covered in the course.
Evaluation 1/7
Evaluation 2/7
Evaluation 3/7
Evaluation 4/7
Evaluation 5/7
Evaluation 6/7
Evaluation 7/7
Certificate
Congratulations!
Certificate of Completion
To receive an Open Badge for this course, please contact the local project partner: Kaunas University of Technology.
Sources
Sources for text:
- Allcott, H., & Greenstone, M. (2012). Is there an energy efficiency gap? Journal of Economic Perspectives, 26(1), 3–28.
- Ellabban, O., Abu-Rub, H., & Blaabjerg, F. (2014). Renewable energy resources: Current status, future prospects and their enabling technology. Renewable and Sustainable Energy Reviews, 39, 748–764.
- Epstein, P. R., & Selber, J. (2020). Oil: A life cycle analysis of its health and environmental impacts. The Center for Health and the Global Environment, Harvard Medical School.
- European Commission. (2024). Energy and the Green Deal.
- European Commission. (2025). Renewable energy directive: Targets and rules. Retrieved from https://energy.ec.europa.eu/topics/renewable-energy/renewable-energy-directive-targets-and-rules_en.
- Global Wind Energy Council. (2021). Global Wind Report 2021.
- International Energy Agency (IEA). (2021). Key world energy statistics 2021: Final consumption.
- International Energy Agency (IEA). (2022). Energy Efficiency 2022. Paris: IEA.
Sources
Sources for text:
- International Energy Agency (IEA). (2025). World energy balances: Overview. Retrieved from https://www.iea.org/reports/world-energy-balances-overview/world.
- International Hydropower Association. (2020). 2020 Hydropower Status Report.
- International Renewable Energy Agency (IRENA). (2020). Renewable power generation costs in 2019.
- International Renewable Energy Agency (IRENA). (2021). World Energy Transitions Outlook: 1.5°C Pathway. Abu Dhabi: IRENA.
- Rockström, J., Gaffney, O., Rogelj, J., Meinshausen, M., Nakicenović, N., & Schellnhuber, H. J. (2017). A roadmap for rapid decarbonization. Science, 355(6331), 1269–1271.
- Schmidt, O., Melchior, S., Hawkes, A., & Staffell, I. (2019). Projecting the future levelized cost of electricity storage technologies. Joule, 3(1), 81–100
- Wang, Q., Hou, Z., Guo, Y., Huang, L., Fang, Y., Sun, W., & Ge, Y. (2023). Enhancing energy transition through sector coupling: A review of technologies and models. Energies, 16(13), 5226
Sources
Sources for figures and videos: [1] Energy forms. Retrieved from https://www.pexels.com/photo/low-angle-photo-of-nuclear-power-plant-buildings-emtting-smoke-3044470/ [2] Energy sources. Retrieved from https://www.freepik.com/free-vector/natural-environmental-resources-set-with-wind-power-solar-energy-symbols-flat-isolated-vector-illustration_26760398.htm#fromView=search&page=1&position=1&uuid=46b9776c-afc2-451b-a318-9194bdf10347&query=energy+sources [3] Statistical review of world energy. Data retrieved from https://www.energyinst.org/statistical-review [4] Fossil fuels. Retrieved from https://www.freepik.com/free-photo/climate-change-with-industrial-pollution_21248835.htm#fromView=search&page=1&position=1&uuid=d2ea7216-40bb-4067-98ef-b3d3d36d995f&query=fossil+fuels [5] Energy transition. Retrieved from https://www.freepik.com/free-vector/gradient-carbon-neutral-illustration_27259146.htm#fromView=search&page=1&position=23&uuid=ed2585ed-f55a-4006-8ee1-5fae01cbc6c6&query=energy+transition [6] Renewable energy sources. Retrieved from https://www.pexels.com/photo/silhouette-of-windmills-on-field-1659688/
Sources
Sources for figures and videos: [7] How solar energy is converted into electricity. Retrieved from https://www.youtube.com/watch?v=g4AJgh552v8 [8] How wind energy is converted into electricity. Retrieved from https://www.youtube.com/watch?v=EYYHfMCw-FI [9] How hydropower works. Retrieved from https://www.youtube.com/watch?v=uAXHHMFjpQM [10] How geothermal energy works. Retrieved from https://www.youtube.com/watch?v=ajeeEr5jG9M [11] Wood pellets. Retrieved from https://www.freepik.com/free-photo/stack-wooden-pellets-bio-energy-white-background-isolated_21057760.htm#fromView=search&page=1&position=11&uuid=f150c5b8-fe35-4a9c-b7d9-7ba6f8d1b4ca&query=wood+pellets [12] Renewable energy share in countries. Data retrieved from https://www.eea.europa.eu/en/analysis
Level completed!
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the National Agency. Neither the European Union nor National Agency can be held responsible for them.
1.2 Energy Sources
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Transcript
Energy Sources
Level 2: Intermediate
Let's go!
Introduction
Energy plays a fundamental role in shaping modern society, driving economic development, and ensuring technological progress. As global energy demand increases, the need for sustainable and efficient energy use becomes more urgent. This course offers an in depth exploration of energy sources, their production methods, and the complex relationship between energy consumption and environmental sustainability. You will explore theorethical background, reflection questions, and exapes to develop a critical understanding of energy sources, also challenges and solutions related to it. By the end of this course, you will be able to critically examine various energy sources, assessing their benefits and risks, economic viability, and environmental impact.
Start Course
Energy Sources Level 2: Intermediate
Objectives
Modules
Exercises
Evaluation
Objectives
What will you learn?
Modules
Module 3: Fossil fuels and decarbonization pathways
Module 1: Introduction to the objectives
Module 2: What is energy and its sources?
Module 4: Renewable energy sources
Module 5: Energy transition and policies
Module 6: Conclusions
What is energy and its transformation
Energy is the capacity to perform work or cause change and is fundamental to all processes in nature and technology. From heating homes to running industrial machinery, energy is at the core of modern civilization. There are various forms of energy, including kinetic (motion), thermal (heat), electrical, chemical, nuclear, and radiant (light) energy. These forms can be converted into one another through different processes.
Energy transformation occurs in everyday life. For example, in a power plant, chemical energy from fuel is converted into thermal energy, which is then transformed into mechanical energy to drive turbines, eventually generating electricity. Understanding these transformations helps us optimize energy use, increase efficiency, and reduce waste in both daily activities and large-scale industrial applications.
Figure 1. Energy forms [1]
How does energy transformation impact your daily life? Can you think of an example where inefficient energy conversion leads to energy loss?
Energy Sources
Energy sources are categorized into non-renewable and renewable
Renewable energy sources are derived from natural processes that replenish themselves over time. These include solar, wind, hydropower, biomass, and geothermal energy. They offer long term sustainability but require technological advancements for efficient storage and distribution.✅ Environmentally friendly with lower carbon emissions.✅ Sustainable and does not deplete over time. ❌ Higher initial investment costs and infrastructure development required.❌ Dependent on external factors like weather conditions (e.g., solar and wind energy).
Non-renewable energy sources are finite resources that deplete over time, such as coal, oil, natural gas, and uranium for nuclear power. While they provide a high energy output and infrastructure stability, their continued use raises concerns about resource depletion and environmental impact.✅ Provides a stable and reliable energy supply.✅ Infrastructure is already well-developed in most countries.❌ Contributes to climate change and environmental pollution.❌ Finite resources that will eventually be depleted.
Figure 2. Energy sources [2]
Energy consumption globally and in the European Union
Figure 3. Energy consumption by its sources [3]
What factors influence a country's decision to rely more on renewable or non-renewable energy sources? How does geography, economy, and policy shape these choices?
Benefits:
Nuclear energy: benefits and risks
Nuclear energy is generated through nuclear fission, where atomic nuclei are split to release a tremendous amount of heat. This heat is then used to produce steam, which drives turbines to generate electricity. Unlike fossil fuels, nuclear power does not produce direct carbon dioxide emissions, making it a low-carbon energy source. However, it is not classified as renewable because it depends on finite resources.
Risks:
France generates over 70% of its electricity from nuclear power, reducing its reliance on fossil fuels. However, debates continue on whether nuclear should remain a key part of the energy transition or be replaced entirely by renewables.
Comparison of energy sources
Different energy sources vary in economic, availability, reliability, and environmental aspects
Table 1. Comparison of energy sources
Fossil fuels
Fossil fuels — coal, oil, and natural gas — are formed from the remains of ancient plants and animals that have been subjected to heat and pressure over millions of years. They are non-renewable, meaning they are long to form and are being consumed faster than they are replenished. Fossil fuels became the primary energy source due to their high energy density, reliability, and well-established infrastructure. These fuels have been the backbone of industrialization, providing energy for electricity, transportation, and manufacturing. They have powered economic growth for over a century and currently supply over 80% of the world's energy needs. Their affordability and existing supply chains make them difficult to phase out entirely in the short term.
Figure 4. Fossil fuels [4]
Coal, oil, natural gas
Natural gas
Oil
Coal
Which of these fossil fuels do you think will be the hardest to replace? Why?
Environmental impact and depletion
Main environmental issues
Resource depletion
Coal: Coal is the most abundant fossil fuel, but high-grade coal reserves are depleting in many regions. Estimated to last another 100-150 years, but extraction is declining due to environmental concerns.Oil: Oil is becoming more difficult to extract, requiring deep-sea drilling, tar sands extraction, and fracking. Global oil reserves could be depleted in the next 50 years based on current consumption rates.Natural gas: Estimated to last 50-60 years, but new reserves are occasionally discovered. However, reserves are finite, and extraction methods like hydraulic fracturing (fracking) have raised environmental concerns.
Greenhouse gas emissions: Burning fossil fuels releases large amounts of carbon dioxide (CO₂) and methane (CH₄), which contribute to global warming and climate change. The energy sector accounts for nearly 75% of global greenhouse gas emissions. Air pollution: Power plants, vehicles, and industry emit sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulate matter, leading to smog, acid rain, and respiratory diseases. Oil spills and habitat destruction: Offshore drilling and oil transportation accidents result in major environmental disasters, affecting marine life and coastal ecosystems.
The Deepwater Horizon oil spill (2010) released nearly 4.9 million barrels of crude oil into the Gulf of Mexico, causing severe damage to marine ecosystems, local fisheries, and coastal economies.
Pathways for decarbonization
Decarbonization aims to reduce carbon dioxide (CO₂) emissions from energy production and consumption.
3. Carbon capture and storage
1. Transition to renewable sources
4. Development of electrification
2. Enhance energy efficiency
How to reduce dependency on fossil fuels?
Reducing reliance on fossil fuels can lower energy costs and contribute to sustainability
- Switch to renewable energy providers ☀️
Choose electricity providers that use renewable energy sources. Install solar panels, solar water heaters, or small wind turbines if possible.- Improve home energy efficiency 🏠
Using energy-efficient lighting, smart thermostats, and properly insulated homes reduces energy demand and fossil fuel consumption.- Use low-carbon transportation options 🚲
Walk, bike, use of public transport or car-sharing services instead of driving short distances by car can cut personal fuel consumption and emissionsFigure 5. Energy transition [5]
Why did fossil fuels remain the dominant energy source for so long, and what are the key challenges in moving away from them?
Renewable energy sources
Definition of renewable energy
Why is renewable energy important?
Figure 6. Renewable energy sources [6]
'A transition to clean energy is about making an investment in our future' - Gloria Reuben
Solar energy
How solar energy works:Solar energy is harnessed using photovoltaic (PV) panels, which convert sunlight into electricity through the photoelectric effect. Alternatively, concentrated solar power (CSP) systems use mirrors to focus sunlight and generate heat, which drives turbines to produce electricity.Benefits:Abundant and widely available, solar panels can be installed on homes, businesses, and large-scale farms with low operational costs.Challenges:Solar panels generate power only when sunlight is available. Although prices have dropped significantly, installation and battery storage remain expensive for many households.
Video 1. How solar energy is converted into electricity [7]
Wind energy
How wind energy works:Wind turbines convert kinetic energy from the wind into mechanical energy, which is then converted into electricity by a generator. Offshore wind farms are increasingly used due to their higher wind speeds and energy potential.Benefits:A single modern wind turbine can power thousands of homes per year. Wind energy produces no direct emissions and requires little water compared to fossil fuel plants.Challenges: Wind speeds fluctuate, requiring storage solutions or grid balancing mechanisms. Some communities oppose wind farms due to their visual impact and noise levels.
Video 2. How wind energy is converted into electricity [8]
The Hornsea Wind Farm in the UK, one of the largest offshore wind farms, supplies electricity to over one million homes while reducing carbon emissions significantly.
Hydropower
How hydropower works:Hydropower uses the energy of moving water to turn turbines, which generate electricity. Run-of-river, reservoir-based, and tidal power are the three main types of hydropower.Benefits:Hydropower plants have lifespans exceeding 50 years and achieve efficiencies of over 90%. Unlike solar and wind, hydropower provides continuous energy generation.Challenges: Dams disrupt river ecosystems, fish migration, and sediment transport impacting biodiversity. Building large-scale hydroelectric plants requires significant infrastructure costs and long construction timelines.
Video 3. How hydropower works [9]
Geothermal energy
How geothermal energy works:Geothermal energy harnesses heat from beneath the Earth's crust by drilling wells into geothermal reservoirs to produce steam, which powers turbines to generate electricity. Direct use applications include district heating, industrial processes, and greenhouse farming.Benefits:Continuous, reliable power that can be used for both electricty and heating. Geothermal heat pumps can cut heating and cooling costs by up to 60% compared to fossil fuel systems.Challenges: Limited to regions with geothermal activity. Requires high initial investment for drilling and infrastructure.
Video 4. How geothermal energy works [10]
Iceland generates nearly 90% of its heating needs from geothermal energy, making it a global leader in utilizing this renewable source for sustainable development.
Biomass energy
Benefits:
Biomass energy is derived from organic materials such as wood, agricultural residues, animal waste, and dedicated energy crops. It can be burned directly for heat, converted into biofuels (e.g., ethanol, biodiesel), or processed into biogas for electricity generation. Most common forms of biomass are wood pellets, biogas, and biodiesel.
Challenges:
Which of renewable energy sources do you think has the most potential for global adoption?
Figure 7. Wood pellets [11]
Global and the European Union energy transition goals
Energy transition refers to the global shift from fossil fuel-based energy systems to renewable and low-carbon energy sources. This process involves changes in infrastructure, policies, and consumption patterns to reduce environmental impact and improve energy security.
Paris Agreement (2015) is global international agreement that sets global targets to limit temperature rise below 2°C. Over 190 countries are committed to set national climate targets, phasing out coal, and investing in renewables.
European Union transition goals
By 2050:
By 2030:
2050
2030
1990
What are the biggest obstacles to achieving a full energy transition, and how can they be addressed?
Renewable energy in Lithuania, Greece, Italy, Bulgaria, and Austria energy mix
The share of renewable energy in the total energy mix varies significantly between countries due to differences in natural resources, policy frameworks, and investment priorities. Lithuania and Austria are leading in renewable energy adoption, with high shares of wind and hydropower, while Italy and Greece are rapidly expanding their solar energy capacity. Bulgaria has historically relied on coal, but its transition includes growing investments in wind and biomass energy. Still, a significant gap can be noticed between share in electricity and total energy consumption. While renewable sources contribute substantially to electricity production, their share in overall energy use remains lower due to continued reliance on fossil fuels in sectors like transportation and heating.
Figure 8. Renewable energy share in countries (2023) [12]
What factors influence the choice of energy source in different countries?
National energy strategies in Lithuania, Greece, Italy, Bulgaria, and Austria
Lithuania
Greece
Italy
Bulgaria
Austria
Energy independence and geopolitics
Why is energy independence important?
Economic and social impacts of energy instability
Reduces dependency on external energy suppliers, making countries more resilient to geopolitical tensions. Ensures stable and secure energy supply, reducing risks of energy shortages and price shocks. Encourages national investments in renewable energy, fostering local industry growth and job creation.
Rising energy prices affect consumers and industries, increasing the cost of living and slowing economic growth.Energy poverty becomes a growing concern, as vulnerable populations struggle to afford electricity and heating. Disruptions in industrial production due to fuel shortages can lead to job losses and inflation.
Transitioning towards energy security
How wars affect energy prices?
Expanding renewable energy capacity reduces reliance on imported fossil fuels and stabilizes energy costs.Investing in energy storage and smart grids ensures more efficient distribution and resilience. Diversifying energy imports and building regional energy alliances enhance supply security.
The Russia-Ukraine war (2022) led to unprecedented spikes in natural gas prices in Europe, prompting urgent energy diversification measures. Conflicts in major oil and gas producing regions cause supply disruptions and price volatility. Past conflicts like the 1973 Oil Crisis showcased how geopolitical instability can cripple economies reliant on fossil fuel imports.
National strategies to increase energy independence
How countries are reducing dependence on fossil fuels import?
Expanding renewable energy capacity (solar, wind, hydropower). Governments provide subsidies, tax incentives, and funding to accelerate the transition to renewables.
Battery storage, hydrogen production, and smart grids are key to ensuring a stable supply of electricity from renewables.
Countries are seeking alternative energy suppliers i. e. invest in liquefied natural gas (LNG) terminals to reduce reliance on natural gas of a single country.
Lithuania: LNG terminal for gas diversification to eliminate dependence on Russian gas imports; heavy investment in wind energy. Greece: Accelerating solar and wind energy projects; interconnection projects with other EU countries. Italy: Increasing solar, wind, and hydrogen production, particularly in southern regions; interconnections with neighboring countries. Bulgaria: Transitioning from coal to a mix of natural gas and renewables; modernizing its energy grid for better efficiency. Austria: Strong focus on hydropower expansion; increasing cross-border energy cooperation with Germany and Switzerland for a more stable energy supply.
Which of these strategies seems the most effective? What challenges might these countries face in implementing them?
Conclusions
The transition to sustainable energy is not just a technological shift but a societal transformation. What actions can individuals, businesses, and policymakers take to accelerate this transition?
Exercises
Exercise 2 Household energy audit
Exercise 1 Compare energy source
Identify areas for energy savings in homes and understand the personal energy consumption patterns.
Evaluate different energy sources and recognize the factors influencing energy choices.
Exercise 1. Compare energy sources
Exercise 2. Household energy audit
questions to consider?
instructions
Evaluation
Quiz
Evaluation 1/7
Evaluation 2/7
Evaluation 3/7
Evaluation 4/7
Evaluation 5/7
Evaluation 6/7
Evaluation 7/7
Certificate
Congratulations!
Certificate of Completion
To receive an Open Badge for this course, please contact the local project partner: Kaunas University of Technology.
Sources
Sources for text:
Sources
Sources for text:
Sources
Sources for figures and videos: [1] Energy forms. Retrieved from https://www.pexels.com/photo/low-angle-photo-of-nuclear-power-plant-buildings-emtting-smoke-3044470/ [2] Energy sources. Retrieved from https://www.freepik.com/free-vector/natural-environmental-resources-set-with-wind-power-solar-energy-symbols-flat-isolated-vector-illustration_26760398.htm#fromView=search&page=1&position=1&uuid=46b9776c-afc2-451b-a318-9194bdf10347&query=energy+sources [3] Statistical review of world energy. Data retrieved from https://www.energyinst.org/statistical-review [4] Fossil fuels. Retrieved from https://www.freepik.com/free-photo/climate-change-with-industrial-pollution_21248835.htm#fromView=search&page=1&position=1&uuid=d2ea7216-40bb-4067-98ef-b3d3d36d995f&query=fossil+fuels [5] Energy transition. Retrieved from https://www.freepik.com/free-vector/gradient-carbon-neutral-illustration_27259146.htm#fromView=search&page=1&position=23&uuid=ed2585ed-f55a-4006-8ee1-5fae01cbc6c6&query=energy+transition [6] Renewable energy sources. Retrieved from https://www.pexels.com/photo/silhouette-of-windmills-on-field-1659688/
Sources
Sources for figures and videos: [7] How solar energy is converted into electricity. Retrieved from https://www.youtube.com/watch?v=g4AJgh552v8 [8] How wind energy is converted into electricity. Retrieved from https://www.youtube.com/watch?v=EYYHfMCw-FI [9] How hydropower works. Retrieved from https://www.youtube.com/watch?v=uAXHHMFjpQM [10] How geothermal energy works. Retrieved from https://www.youtube.com/watch?v=ajeeEr5jG9M [11] Wood pellets. Retrieved from https://www.freepik.com/free-photo/stack-wooden-pellets-bio-energy-white-background-isolated_21057760.htm#fromView=search&page=1&position=11&uuid=f150c5b8-fe35-4a9c-b7d9-7ba6f8d1b4ca&query=wood+pellets [12] Renewable energy share in countries. Data retrieved from https://www.eea.europa.eu/en/analysis
Level completed!
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