The Future of Energy: A Comprehensive Guide to Energy Sources, Technologies, and Challenges

Posted on Jun 20, 2024 in Geology

Economic Axis

Energy and Economic Growth

• Industrial societies require substantial amounts of energy.
• The finite nature of energy reserves implies their eventual depletion.
• The current economic model’s fuel consumption is unsustainable.
• Based on current consumption rates, coal will be depleted in 131 years, oil in 58 years, and natural gas in 47 years.
• Electricity production serves as an indicator of economic development.

Strategic Axis

Energy Independence: Security and Stability

• The oil crisis exposed the vulnerability of Western economies.
• Energy plays a crucial strategic role.
• All territories strive for energy independence by minimizing external energy imports and maximizing national energy generation.
• Energy Independence (IE) = (National Energy Production / Total Energy Used) * 100. If IE > 100, a country has surplus energy (e.g., Saudi Arabia); if IE

Ecological Axis

Environmental Impact of Energy

• Energy generation and consumption in human activities have the most significant environmental impact.
• Greenhouse gas (GHG) concentrations are projected to double by 2100, potentially leading to a global temperature increase of around 6°C.
• Energy-related CO2 emissions are expected to rise by 45% by 2030, with China, India, and the Middle East being the primary contributors.
• By 2030, only the European Union and Japan are projected to emit less CO2 than in 1990.

Key Energy Indicators

• Kilograms of Oil Equivalent per Capita (kgOE): Represents the number of liters of oil consumed per person, providing an indication of energy access.
• Energy Intensity (toe/M€): Measures the amount of energy required to generate €1,000,000, reflecting a country’s industrial and economic development. Lower energy intensity signifies greater efficiency and a more sustainable economy.

Linear Economy Model and Its Limits

The linear economy model (Take-Make-Waste), prevalent since the Industrial Revolution, has reached its limits. Earth’s finite resources cannot sustain this model indefinitely. The rise of consumer society since 1950, fueled by advertising, credit, and planned obsolescence, has exacerbated the problem.

Peak Oil

The concept of peak oil refers to the point at which global oil production reaches its maximum and begins to decline. While initially predicted for 2010, peak oil has been delayed due to factors such as:

• Reduced consumption in China and the EU.
• Increased US production through fracking.
• Geopolitical factors, including wars in the Middle East and North Africa (although their impact has been relatively small).
• Lower prices from Saudi Arabia to maintain market share.

Addressing the Energy Challenge

Potential Solutions

• Transition to 100% renewable energy sources.
• Exploration of new energy sources with reduced environmental impact.
• Enhancement of energy efficiency.
• Adoption of a circular economy model.

EU Climate and Energy Framework 2023 Objectives

• 40% reduction in GHG emissions.
• 32% of energy production from renewable sources.
• 32.5% improvement in energy efficiency.

Challenges to Full Electrification

• Limited energy availability due to resource scarcity.
• Material constraints in developing renewable energy technologies, which often rely on fossil fuels for their production.
• Restricted applicability of electricity, accounting for only 20% of total primary energy use. Electrifying sectors like marine and air transportation, mining, industrial processes, and certain chemical plants poses significant challenges.

The Sun: Earth’s Primary Energy Source

The sun is the primary energy source for Earth, followed by gravitation and inner Earth energy. The main unit for energy generation is the watt-hour (Wh), where 1 Wh = 3600 joules (J).

Units Used in Energy Balances

• Ton of Oil Equivalent (TOE): Represents the amount of energy equivalent to one ton of petroleum.
• Ton: Refers to the amount of heat released by burning one ton of crude oil. 1 Ton = 42 gigajoules (GJ) = 11,630 kilowatt-hours (kWh). 1 barrel of oil (159 liters) = 0.1369 Ton.
• Coal: 1.5 tons of coal = 1 TOE. 1 ton of coal = 7753 kWh.
• Natural Gas (at 1 atmosphere and 0°C): 109 cubic meters (m3n) = 35,109 cubic feet (ft3n) = 0.9 million TOE (Mtoe). 1 m3n = 10.46 kWh.

Energy Return on Investment (EROI)

EROI, also known as Energy Return on Energy Invested (TRE), is a crucial metric for evaluating the efficiency of energy sources. It is calculated as:

EROI = (Energy Obtained) / (Energy Invested)

• EROI is used to compare and select energy projects.
• A minimum EROI of 3 to 5 is generally considered viable.
• Non-renewable resources typically have an EROI between 5 and 12.
• Historically, EROI for oil was around 100 in the 1940s, declining to 30 in the 1970s and currently ranging between 5 and 12.
• Unconventional oil reserves often have an EROI below 1.

Different Energy States

• Primary Energy: Energy extracted directly from a source, such as natural gas, coal, geothermal, or petroleum.
• Secondary Energy: Energy derived from a primary energy source, such as gasoline or diesel.
• Useful Energy/Final Energy: Energy used directly to meet specific needs, such as electrical or thermal energy.

Embodied Energy

Embodied energy refers to the total primary energy consumed throughout a material’s life cycle, from extraction to disposal and recycling.

Energy System

An energy system encompasses the technical, economic, and social processes involved in transforming primary energy into useful energy to satisfy societal needs. Energy losses occur during these conversion processes due to efficiency limitations.

Energy Accounting

Energy accounting involves tracking energy flows within a system. The balance is calculated as:

Balance = Energy In – Energy Out

• Energy In: Primary energy production, net imports (imports – exports).
• Energy Out: Conversion losses, energy industry’s own consumption, transportation and distribution losses, non-energy uses.
• Balance: Final consumption in industry, transportation, residential, commercial, and agricultural sectors.

International Energy Agency (IEA)

The IEA assesses global energy consumption and production trends. Its World Energy Outlook report provides energy perspectives and forecasts.

World Energy Demand

• Global energy demand is projected to be 45% higher in 2030 than in 2006, with an annual growth rate of 1.6%.
• China and India are expected to account for 50% of this demand growth.
• Coal demand is anticipated to increase.
• OECD countries will contribute only 13% to the total growth.
• Fossil fuels are projected to remain the dominant energy source until 2030.

World Energy Supply

• Approximately one-third of the world’s estimated oil reserves (3.5 billion barrels) have been extracted.
• The primary risk to energy supply until 2030 is not resource depletion but insufficient investment.
• OPEC is projected to account for 51% of global oil production in 2030.

Total Energy Consumption in 2021

• Global energy consumption in 2021 was 595.15 exajoules (EJ).
• Spain consumed 5.59 EJ, representing 0.9% of the total.
• Oil, natural gas, and coal were the primary energy sources, while renewables accounted for approximately 17%.

EU Energy Strategy (2008-2020): 20-20-20 Program

• 20% reduction in GHG emissions.
• 20% increase in renewable energy generation (10% in transportation).
• 20% improvement in energy efficiency.

EU Long-Term Strategy 2050

• The EU aims to achieve climate neutrality by 2050, with net-zero GHG emissions.

Energy Dependence

Energy dependence refers to the extent to which a country relies on energy imports to meet its needs. Spain, for instance, has a high energy dependence, importing around 70% of its total energy.

Petroleum

Formation and Composition

Petroleum, a fossil fuel, originates from the decomposition of ancient marine organisms (plants, animals, and plankton) buried under layers of sediment over millions of years. The organic matter undergoes chemical transformations under high pressure and temperature, resulting in the formation of hydrocarbons.

Petroleum Resources

Petroleum resources are broadly categorized into three types:

• Paraffinic: Rich in aliphatic hydrocarbons, known for their high energy content.
• Alicyclic: Contain a mixture of alicyclic, asphaltic, and aromatic hydrocarbons.
• Asphaltic: Predominantly composed of aromatic and asphaltic hydrocarbons.

Petroleum Exploration and Extraction

Modern drilling technologies enable the extraction of petroleum from depths of up to 3,000 meters. In offshore operations, deposits can be located at even greater depths, requiring specialized platforms. The estimated remaining oil reserves, based on current consumption rates, are projected to last for approximately 57 years.

Non-Conventional Oil and Gas Reserves

• Tar Sands: Deposits containing heavy hydrocarbons that can be converted into synthetic crude oil through energy-intensive processes.
• Oil Shales: Sedimentary rocks containing organic matter that can be converted to oil or gas through heating and extraction methods.

Super Energy Basin

A super energy basin is a geological region with exceptionally large reserves of energy resources, such as oil, natural gas, coal, or uranium.

Potential Super Energy Basins

These are areas suspected of holding vast energy reserves but have not yet been fully explored or developed due to factors like limited investment or technological constraints.

Disadvantaged Basins

Regions that may contain energy resources but are challenging to access due to technical difficulties or other factors.

Global Oil Consumption and Production

• The United States is the largest producer and consumer of oil globally.
• China is the second-largest oil consumer.
• World oil consumption in 2021 was 4,245.7 million tons.
• Spain consumed 57.3 million tons, accounting for 1.35% of global consumption.

Oil Distillation and Refining

Crude oil is a complex mixture of hydrocarbons that must be refined to separate it into usable products. Fractional distillation is the primary method used in oil refineries. The process involves heating the crude oil, causing it to vaporize and separate into different fractions based on their boiling points. Key products obtained from oil distillation include:

• Gasoline: Used as fuel for spark-ignition engines.
• Kerosene: Used as jet fuel, heating oil, and in some industrial processes.
• Diesel Fuel: Used as fuel for diesel engines.
• Fuel Oil: Used as fuel for industrial boilers and furnaces.

Cracking and Reforming

These are additional refining processes used to convert heavier hydrocarbon fractions into lighter, more valuable products. Cracking breaks down large hydrocarbon molecules into smaller ones, while reforming rearranges the molecular structure of hydrocarbons to improve their properties.

Fracking

Hydraulic fracturing, or fracking, is a controversial technique used to extract oil and natural gas from shale rock formations. The process involves injecting a high-pressure mixture of water, sand, and chemicals into the rock to create fractures, allowing the trapped hydrocarbons to flow out.

Advantages of Fracking

• Access to previously inaccessible oil and gas resources.
• Increased domestic oil and gas production, potentially reducing reliance on imports.
• Job creation in the oil and gas industry.

Disadvantages of Fracking

• Potential contamination of groundwater resources with fracking fluids.
• Increased seismic activity in areas with fracking operations.
• Air pollution from methane emissions and other pollutants released during the fracking process.
• Large water consumption in fracking operations, potentially straining water resources in arid regions.

Tar Sands

Tar sands, also known as oil sands, are deposits of sand or clay mixed with bitumen, a highly viscous form of petroleum. Extracting oil from tar sands is an energy-intensive process that involves mining the sands and then separating the bitumen using heat and solvents. Environmental concerns associated with tar sands exploitation include habitat destruction, greenhouse gas emissions, and water pollution.

Coal

Formation and Composition

Coal is a fossil fuel formed from the accumulation of plant matter over millions of years. The plant matter, buried under layers of sediment, undergoes chemical and physical changes due to pressure and heat, transforming it into coal. Coal is primarily composed of carbon, along with varying amounts of hydrogen, oxygen, nitrogen, sulfur, and other trace elements.

Types of Coal

Coal is classified into different types based on its carbon content, energy content, and other properties. The most common types of coal include:

• Anthracite: The highest rank of coal, with the highest carbon content and energy content. It is hard, black, and shiny.
• Bituminous Coal: The most abundant type of coal, with a lower carbon content than anthracite. It is used for electricity generation and steel production.
• Subbituminous Coal: Lower in carbon content than bituminous coal, it is often used for electricity generation.
• Lignite: The lowest rank of coal, with the lowest carbon content and energy content. It is soft, brown, and often used for electricity generation.

Coal Uses

Coal has been a major source of energy for centuries, primarily used for:

• Electricity Generation: Coal-fired power plants generate electricity by burning coal to heat water, producing steam that drives turbines.
• Steel Production: Coal is used as a reducing agent in blast furnaces to extract iron from iron ore.
• Cement Production: Coal is used as a fuel in cement kilns.
• Industrial Processes: Coal provides heat and energy for various industrial processes, such as manufacturing, mining, and chemical production.

Environmental Impacts of Coal

Coal combustion is a major source of air pollution, contributing to:

• Greenhouse Gas Emissions: Coal combustion releases significant amounts of carbon dioxide, a major greenhouse gas contributing to climate change.
• Acid Rain: Sulfur dioxide and nitrogen oxides released from coal combustion react with water vapor in the atmosphere to form sulfuric acid and nitric acid, which fall to the ground as acid rain.
• Respiratory Problems: Particulate matter emitted from coal combustion can penetrate deep into the lungs, causing respiratory problems, cardiovascular disease, and other health issues.
• Mercury Pollution: Coal combustion releases mercury into the environment, which can accumulate in fish and other seafood, posing health risks to humans.

Clean Coal Technologies

Clean coal technologies aim to reduce the environmental impact of coal combustion. These technologies include:

• Carbon Capture and Storage (CCS): CCS technologies capture carbon dioxide emissions from coal-fired power plants and store them underground, preventing their release into the atmosphere.
• Coal Gasification: Coal gasification converts coal into a synthetic gas, primarily composed of hydrogen and carbon monoxide, which can be used as a fuel for electricity generation or as a feedstock for chemical production.
• Fluidized Bed Combustion: This technology burns coal in a fluidized bed of limestone, which captures sulfur dioxide emissions, reducing acid rain.

Natural Gas

Formation and Composition

Natural gas is a fossil fuel formed from the decomposition of organic matter over millions of years. It is primarily composed of methane, a colorless, odorless gas. Natural gas is often found in association with oil deposits.

Natural Gas Extraction and Processing

Natural gas is extracted from underground reservoirs using drilling techniques. Once extracted, it undergoes processing to remove impurities, such as water vapor, carbon dioxide, and sulfur compounds.

Natural Gas Transportation

Natural gas can be transported through pipelines or as liquefied natural gas (LNG).

• Pipelines: Pipelines are the most common method for transporting natural gas over land. Natural gas pipelines can span thousands of kilometers, connecting production areas to consumers.
• Liquefied Natural Gas (LNG): Natural gas can be cooled to -162°C, at which point it becomes a liquid, known as LNG. LNG occupies about 1/600th the volume of natural gas in its gaseous state, making it more efficient to transport over long distances by sea.

Natural Gas Uses

Natural gas is a versatile fuel used for various purposes, including:

• Electricity Generation: Natural gas power plants generate electricity by burning natural gas in turbines.
• Heating: Natural gas is used for heating homes, businesses, and industrial processes.
• Cooking: Natural gas stoves and ovens are common in many households.
• Transportation: Natural gas can be used as a fuel for vehicles, either in compressed natural gas (CNG) or LNG form.
• Industrial Feedstock: Natural gas is a feedstock for the production of fertilizers, plastics, and other chemicals.

Environmental Impacts of Natural Gas

While natural gas is considered a cleaner-burning fossil fuel than coal, it still has environmental impacts:

• Greenhouse Gas Emissions: Natural gas combustion releases carbon dioxide, a greenhouse gas, although in lower quantities than coal.
• Methane Leaks: Methane, the primary component of natural gas, is a potent greenhouse gas. Leaks from natural gas pipelines and production facilities contribute to methane emissions.
• Water Contamination: Fracking, a technique used to extract natural gas from shale formations, can contaminate groundwater resources.

Nuclear Energy

Nuclear Fission

Nuclear fission is the process of splitting a heavy atomic nucleus, such as uranium-235 or plutonium-239, into two or more lighter nuclei, releasing a tremendous amount of energy in the form of heat. This process is the basis for nuclear weapons and nuclear power plants.

Nuclear Power Plants

Nuclear power plants use nuclear fission to generate electricity. The heat released from fission is used to produce steam, which drives turbines connected to generators.

Nuclear Fuel Cycle

The nuclear fuel cycle encompasses the processes involved in mining, processing, using, and disposing of nuclear fuel. Key stages in the nuclear fuel cycle include:

• Uranium Mining: Uranium ore is extracted from the ground.
• Uranium Milling: The ore is crushed and processed to extract uranium oxide (U3O8), also known as yellowcake.
• Uranium Enrichment: Natural uranium contains only about 0.7% of the fissile isotope uranium-235. Enrichment increases the concentration of uranium-235 to make it suitable for use in nuclear reactors.
• Fuel Fabrication: Enriched uranium is converted into fuel pellets, which are then assembled into fuel rods. Fuel rods are bundled together to form fuel assemblies, which are loaded into nuclear reactors.
• Nuclear Reactor: In the reactor, nuclear fission occurs, releasing heat that is used to generate electricity.
• Spent Fuel Storage: After use in a reactor, spent fuel assemblies are highly radioactive and generate significant heat. They are initially stored in pools of water at the reactor site to cool down and allow some of the radioactivity to decay.
• Nuclear Waste Disposal: The long-term disposal of high-level radioactive waste, such as spent nuclear fuel, is a significant challenge. Options include geological repositories, where waste is buried deep underground in stable geological formations.

Types of Nuclear Reactors

There are various types of nuclear reactors, each with its own design and characteristics. Common types include:

• Pressurized Water Reactor (PWR): The most common type of reactor, PWRs use water as both a coolant and a moderator.
• Boiling Water Reactor (BWR): BWRs also use water as a coolant and moderator, but water is allowed to boil in the reactor core.
• CANDU Reactor: CANDU reactors use natural uranium as fuel and heavy water as a coolant and moderator.
• Fast Neutron Reactor (FNR): FNRs use fast neutrons to sustain the fission chain reaction and can breed more fissile material than they consume.

Advantages of Nuclear Energy

• Low Greenhouse Gas Emissions: Nuclear power plants do not emit greenhouse gases during operation, making them a low-carbon source of electricity.
• High Power Output: Nuclear power plants have a high power output, meaning they can generate a significant amount of electricity from a relatively small amount of fuel.
• Reliable Energy Source: Nuclear power plants are not dependent on weather conditions, unlike renewable energy sources such as solar and wind power.

Disadvantages of Nuclear Energy

• Nuclear Accidents: Nuclear power plants can experience accidents that release radioactive material into the environment, as seen in Chernobyl (1986) and Fukushima (2011).
• Nuclear Waste Disposal: The disposal of high-level radioactive waste is a significant challenge, as it remains dangerous for thousands of years.
• Nuclear Proliferation: The technologies and materials used in the nuclear fuel cycle can be diverted for the production of nuclear weapons.
• High Initial Costs: Building nuclear power plants is capital-intensive, requiring significant upfront investment.

Nuclear Fusion

Fusion Reactions

Nuclear fusion is the process of combining two light atomic nuclei, such as isotopes of hydrogen (deuterium and tritium), to form a heavier nucleus, releasing a tremendous amount of energy. Fusion reactions power the sun and other stars.

Fusion Power

Fusion power is a theoretical form of power generation that would harness the energy released from nuclear fusion reactions. Fusion power has the potential to provide a nearly limitless, clean, and safe energy source.

Fusion Reactors

Fusion reactors are experimental devices designed to achieve controlled nuclear fusion reactions. Two main approaches to fusion reactor design are:

• Magnetic Confinement Fusion: This approach uses magnetic fields to confine the hot, ionized gas, known as plasma, in which fusion reactions occur. Examples include tokamaks and stellarators.
• Inertial Confinement Fusion: This approach uses lasers or particle beams to compress and heat a small target containing fusion fuel, typically a mixture of deuterium and tritium.

Challenges of Fusion Power

• Achieving Ignition: Ignition is the point at which a fusion reaction becomes self-sustaining, releasing more energy than is required to maintain it. Achieving ignition is a major scientific and engineering challenge.
• Plasma Confinement: Confining the hot, dense plasma in which fusion reactions occur is extremely difficult.
• Materials Science: Fusion reactors require materials that can withstand the extreme temperatures, pressures, and radiation environments present during fusion reactions.
• Cost and Complexity: Fusion reactors are highly complex and expensive to build and operate.

Potential Benefits of Fusion Power

• Abundant Fuel: Fusion reactions use deuterium, which is abundant in seawater, and tritium, which can be produced from lithium.
• Clean Energy: Fusion reactions do not produce greenhouse gases or long-lived radioactive waste.
• Inherent Safety: Fusion reactions are inherently safe, as they cannot sustain a runaway chain reaction like fission reactions.

Conclusion

s• Maintaining the current economic model and the energy growth is unsustainable and impossible for 2030.• Energy consumption must be reduced by more than 50%.• Renewable energies can be useful but cannot replace fossil fuels.• We have to consume less and make the planet a sustainable place. • This can only be done with a cultural change that gives importance to cooperation and sharing instead of individualism and hoarding.

The sun is the main source of energy in Earth. The second is gravitation and inner Earth energy.Main unit for energy generation is Wh. 1 Wh = 3600 J. 1 Wh=1·J/s  Units used in energy balances: TOE: Amount of energy that is equal to a ton of petroleum.  Ton: Amount of heat released when burning a ton of crude oil. Oil: 1 Ton = 42GJ = 11630 kWh 1 barrel of oil of 159 litres = 0,1369 Ton. Coal: 1,5 tons of coal = 1 TOE1 ton of coal = 7753 kWh Natural gas (must be in 1 atmosphere and 0ºC.)109m3n = 35109 ft3n = 0,9 Mtoe1m3n = 10,46 kWh Additional capacities = Resources – Reserves. Peak oil: Oil extraction is defined as a symmetric curve, when the top is reached, the extraction decays due to the depletion of profitable deposits. While it is decreasing, there are reserves but harder to obtain.
 EROI/TRE (energy return on investment)=(E obtained)/(E invested) ºEROI is used to choose amongst energy projects.ºMinimum EROI must be in between 3 and 5.ºNon-renewable resources have EROI of between 5 and 12.ºIn the 40s the EROI was around 100, in 70s 30 and actually is around 5 and 12.º Non-conventional oil reserves have EROI value below 1. º You cannot stop the production in an oil well. Also, it is an organic fluid, so it degrades with time. When oil price decreases, a crisis is about to come.
Different energy states: Primary energy: Extracted from a deposit and that can deliver useful energy (natural gas, coal, geothermal, petroleum). Secondary energy: Obtained from a primary energy source (gasoline, diesel). Useful energy/Final energy: How we use secondary energy to satisfy needs (electrical energy, thermal energy). Iron and aluminium have mines with high purity, around 5%. 
Embodied energy: It is the primary energy that was used in the whole life cycle of a material. It includes from its extraction to its disposal and recycling. Energy system: Array of technical, economic, and social processes put in action to transform primary energy into useful energy to cover the needs of the society. This conversion processes have some energy loses due to efficiency.  Energy accountingIn (+) ºPrimary energy production ºDifference importation/exportationºExportation
Out (-) ºConversion losses ºInner consumption of energy industries.ºTransportation and distribution losses.ºNon-energetic causes. Balance = In – OutºFinal industry consumption.ºFinal transportation consumption.ºFinal domestic, commercial and agricultural consumption.
International Energy Agency: Evaluates trends in energy consumption & production.
World Energy Outlook: The energetic perspectives from 2006 to 2030 are described. World energy demandº In 2030 energy demand will be 45% higher than in 2006 (1.6% year grow rate)º 50% of the demand will be China and India. Coal demand will increase. ºOECD only 13% of total growth.º Fossil fuels will be top 1 until 2030. World energy supplyº1/3 of the oil barrels in the world (3.5 billion) have been extracted.ºThe risk until 2030 is not the lack of resources but the lack of investment. º Oil production will come from OPEC (51%) in 2030.
Total energy consumption in 2021  595,15 EJ. Spain 5,59 EJ (0,9% of total). ºThe most produced energy comes from oil, natural gas and coal. Renewable sources account for around 17% of the total.
EU energy strategy (2008-2020), 20-20-20 program: ºReduction of GHG emissions by 20% ºIncrease of renewable energies generation by 20% and 10% in transport. ºEnergy efficiency improvement by 20%.
2050 long-term strategyºEU aims to be climate neutral by 2050. Zero GHG emissions.ºThe majority of the energy consumed in 2016 was produced thanks to oil (37%), gas (23%) and coal (15%). We have a small number of renewable sources like hydroelectricity (5%), solar (1%), wind (5%), nuclear (11%). But the numbers are small.This is for the EU, and we can see that hydroelectricity has sudden increases and decreases over time. This is because of the dryness of some years, for example 2023. As we can see, Europe more or less accomplished the objectives from 2020. In Spain for example, we have around 25-30% of energy demand covered by renewable energy. But we still have a 44% of oil and 22% natural gas. 
Energy dependence: Amount of primary energy that a country needs to import in order to supply itself. Spain  is very dependent on energy imports, around 70% of its total energy. Catalonia represent only 5% of total energy renew.
In the fuel station, we can see some numbers that state for:B7: Biodiesel E5: Bioethanol Para conocer el nivel de desarrollo real del país, se usa la Intensidad energética [toe/M€];  tiene en cuenta la eficiencia energética y el uso responsable de la energía. A menor Intensidad energética: – energía usada por unidad de riqueza creada  economía +eficiente.

Petrol: Comes from animal, vegetal, and plankton waste deposited in marine depths and estuaries and covered by sand silt. (C, H, O, S). The wastes have suffered several transformations due to bacterial and anaerobic decomposition in reductive conditions under effect of pressure and temperature. Temperature changes, tectonic movements, and differences of density between sea water & petrol created reservoirs of hydrocarbons within geo favourable conditions (sandbanks, sandstone, limestone
Normally when we have petrol, we also have natural gas. The gas is above, covering the petrol.
Petrol resources are grouped in three categories:• Paraffinic: 4 aliphatic groups (CU H2U+2), 1 acyclic group (CU H2U) and 1 aromatic group (Cyclic CU H2U-6)• Alicyclic: 3 alicyclic groups, 2 asphaltic groups and 1 aromatic group.• Asphaltic: 3 aromatic groups, 2 asphaltic groups, 1 acyclic group.La densidad del petróleo se puede calcular mediante el grado API (ºAPI = (141.5/peso específico) – 131.5). El grado de parafinidad o aromaticidad se mide con el grado de caracterización de Watson (Kw) y con el índice de correlación (IC). La relación C/H va directamente ligada al poder calorífico. The lighter conventional petrol is the paraffinic. Depending on the type of petrol that you have, you will obtain different fractions of final product. On the top of the column, we will obtain GLP (petrol liquated gases).• H2, CH4, propane, ethane, butane. Current drilling technology allows to reach depths of around 3000m. In marine prospections the deposits can be at 3000m depth + 1000 m of water column. In the case of floating platforms 10.000m. Oil will last for around 57 years. Non-conventional reserves of oil and gas:• Tar sands: With relative high concentrations of hydrocarbons, that can be transformed into petrol with a heating process.• Oil shales: Contain organic compounds that can be converted to oil or gas through milling and heating techniques.Super cuenca energética: Región geológica con una cantidad excepcionalmente grande de recursos energéticos, como petróleo o gas natural y otros recursos minerales o energéticos como carbón o uranio.Potenciales super cuencas energéticas: Es un área que se sospecha que tiene reservas de energía en gran escala pero que por falta de inversión o tecnología aún no han sido completamente exploradas o desarrolladas.Cuencas en desventaja: Una región que puede contener recursos energéticos pero que son de difícil acceso, ya sea por naturaleza técnica o por factores x. The main producer of oil is the US and also the main consumer. The second consumer is China. The World oil consumption in 2021 was 4245,7 Mton. Spain 57,3 Mton, 1.35% Considering the proven reserves and the production rate, it is estimated that there is still oil for 57 years at the current production rate. Casablanca platform in front of Tarragona started its operation in 1982 and produced 5.000 barrels per day, but due to its low production yield, it will close in 2025.generates 0,3%  Spanish consumption. Spain imports oil from middle East, Africa, Europe, and America. Oil distillation. Cracking and reforming: Fractional distillation is the technique used to obtain different oil sub products. It includes different steps of evaporation and condensation within a column and depending on the different boiling points of the substances. It produces:• 20-30% gasoline.• 30-45% intermediate products.• 25-50% (fuel-oil). Cracking: Bigger molecules (gasoil and fuel-oil) are broken and then grouped to form smaller molecules (gasoline) using catalyst and under high temperature and pressure conditions.Reforming: Heavier products are obtained via different reactions:• Catalytic polymerization: C3 and C4 olefins are converted into gasoline.• Alquilation: An olefin and a paraffin react using a catalyst.• Isomerization: N-butane is converted in i-butane, n-pentane and n-hexane converted into iso paraffins.• Hydrogenation: In which the octane number of gasoline is increased. Industrial uses of liquid fuels: Usos principales: 50% en el transporte, E. Térmico (industrial y doméstico), ingeniería química. Aplicaciones industriales:• Producción de vapor en calderas• Hornos industriales. Son hornos de cocción hornos de fundición• de vidrio, secado de granos• Hornos metalúrgicos. Son los hornos de crisol, hornos de recocido y tratamientos térmicos, hornos de barras para talleres de laminación, hornos rotatorios de fundición maleable de hierro, etc… Los motores de combustión interna: La aplicación más extendida de los combustibles líquidos derivados del petróleo es su uso en los motores endotérmicos alternativos o motores de combustión interna. Existen dos grandes tipos: • Los de encendido provocado por chispa (ciclos Otto) que funcionan con gasolina y la mezcla aire combustible se enciende debido a una chispa generada por la bujía. • Los de encendido provocado por compresión (ciclo Diesel). En los que la mezcla aire combustible (gasoil) es comprimida y se enciende por haber llegado a la temperatura de auto ignición.

Gasoline: Is the fuel used in spark ignited engines (Otto cycle).• Mixture of hydrocarbons.• Density = 680 g/l.• Energy content 34,78 MJ/litter.One of its key characteristics is its anti-knock index represented by the octane index (OI), that is the volume percentage of i-octane in a mixture i-octane/n-heptane with the same anti-knock characteristic than the used fuel. Some additives can increase the anti-knock like tetraethyl lead or thanks to hydrogenation process in reforming.Kerosene: Is a distillation product with a boiling point between 150-300ºC and its weight is in the middle between gasoline and gasoil. It is used in heating, aviation fuel. Gasoil: it is a distillate with a boiling point between 204-370ºC and is used in diesel engines, to heat and as a solvent. If it’s used in automotive, it is important to consider the cetane index (CI) and a CI of 100 means it is the best diesel fuel. CI=0 is for aromatic hydrocarbons that are the worst. CI is a volumetric ratio in a mixture cetane/alfa-methylnaphthalene that has the same performance than the fuel studied.• Clase A: Diesel cars.• Clase B: Agrarian and naval uses.• Clase C: Home heating. Fuel oil: Is the heaviest product obtained in distillation and reforming processes and is used as an industrial heating fuel in furnaces and boilers. Its high viscosity can be a problem when transporting. Composition  86%C, 12% H2, 0.6% O2, 1.4%S. The presence of S and Na, V, S can have negative effects of corrosion and contaminations. Has an HHV of 10.550 kcal/kg and a LHV of 9.921 kcal/kg. The International Energy Agency (IEA) thought that in 2004 it was the peak oil but after they started to exploit bituminous sands it started to grow again. Now we are more or less stuck. Non-conventional oil is supplying the barrels that conventional oil no longer supplies but the deposits are of lower quality and hard to access. The production of oil in Barcelona comes only from Tarragona. There’s a law in Spain that states that you can’t buy more than a 25% of the total supply to the same exporter.
Why can we no longer use oil? On average, only 35% of the oil contained in a deposit is extracted. There is a lot of petrol the problem is that extracting all of them is not worth it and there’s no investments. When you drill into a deposit, the flow flows to the outside and when the petroleum is extracted the rock collapses, and you lose part of the oil by isolating it.The world oil consumption is approximately 90 million barrels/year.90·106 barrels/day are extracted and 70 of them are through from conventional petrol and 26 barrels/day from non-conventional.
Non-conventional oil types:• Natural gas liquids: Mainly propane and butane.• Biofuels.• Artic and ultra deep crude oil.• Extra heavy oil from tar sands (deposits in Canada and Venezuela).• Light oil from tight rock (fracking oil). Fracking: Is the process of drilling down into the earth before a high-pressure water mixture is directed at the rocks to release the gas inside. Water, sand, and chemicals are injected into the rock at high pressure and allow the gas to flow out. The term fracking refers to how the rock is fractured apart by the high-pressure mixture. The perforator can incline a certain point and that allows to reach the desired point. After the hole is created, explosives are sent there. Then sand, lubricants and water are injected, sand is used to avoid that the breach closes again, and water and lubricants help to succinate the petrol. Advantages:• Allow to access difficult to reach resources of oil and gas.• Has boosted domestic oil production and driven down gas prices in the US.
Inconvenient: It uses huge amounts of water and chemicals and is dangerous for the environment. The main issues are related to the environment and the emission of dangerous chemicals.In the crisis of 2008, fracking techniques began to gain popularity but between 2012 and 2014 the most important fracking had been losing billions of dollars. They have gone into debt believing that an increase in production (that has not come) will end up paying the bill. Economy of the debt.
Tar sands, heavy oils or bitumen cannot be considered liquids since they have densities equivalent to tar. They present problems due to their low fluidity. They require large amounts of steam and pressure to extract them. In addition, it has to undergo refining and upgrading processes to make it useful. These processes require conventional oil and natural gas. Reserves are in Canada and Venezuela.
Situation in Canada:• Natural gas is used to generate steam and then natural gas is added again in the cracking process to create a substance assimilable to conventional crude oil.• The process emits large quantities of natural gas  greenhouse effect. As a result, Canada withdrew from the Kyoto Protocol.• There is not enough natural gas in Canada (peak gas in Canada in 2010) and now US fracking oil is used.• Canadian production has never exceeded 2 million barrels/day

Situation in Venezuela (energetical cannibalism):• A country with an abundance of water but little natural gas and very little infrastructure for the exploitation of this resource.• They have opted to mix the bitumen with oil from the Maracaibo deposits, but they end up losing money because the oil from Maracaibo is top quality and therefore it does not make sense to spend it on improving a crude that is of very low quality.• Oil production has increased but revenues have fallen. Moreover, the peak of Maracaibo’s oil was in 2000.• Venezuela needs to import quality oil or natural gas from someone who wants to do business with him (Algeria and Russia for example) but the profits are lower.• In general, it seems a ruinous investment from an economic and environmental point of view.Why arctic and deep-sea oil are not the solution? The reservoirs are located at great depths and formed by magmatic rock, that is harder to drill than sedimentary rock. For drilling it is necessary to use geolocated floating platforms that move to be on top of the deposit without breaking the pipe, this is really expensive.

Coal: Is a sedimentary rock of organic origin that was formed from plants under non degradable conditions. The valuable reservoirs were generated from massive appearance of plants on Earth 350 million years ago during carboniferous era. Is a solid fuel of vitreous aspect and variable composition, that also contains inorganic compounds and sulphur. Has a complex structure that can differ between coals.Its quality is determined as a function of different criteria such as volatile matter content, fixed carbon content, humidity, heating value. Anthracite is almost pure coal, this one and hulla are the ones used in industry. If we burn hulla in an environment without oxygen, we will obtain gases like (H2, CO2, CO, CH4) but also a solid with a better calorific power, it is refined.
Synthesis gas = CO, H2 f we apply heat to carbon  with a small quantity of oxygen, we will obtain CO+CO2+H2 and if we apply water to CO, we will obtain H2+CO2.CO2 shift  CO+ H20  CO2 + H2 + Q
Coal uses:Thermal energy. Industrial uses. Other fuels: ºGases: CO + H2, CH4.ºLiquids: Diesel/Gasoline.ºSolids. Thermal plants to generate electrical energy.
El carbón se puede usar como: Combustible para la obtención de energía térmica o eléctrica. Obtención de otros combustibles mediante un tratamiento térmico. Si el carbón se purifica se obtiene un carbón con mayor contenido calorífico, si se licua (licuación), se obtienen combustibles líquidos o si se gasifica (gasificación) se obtienen combustibles gaseosos. Vía útil para lograr gasolina o gas natural sin partir del petróleo. The world coal reserves in 2021 were 1074108 million tons. The countries that have more are USA, Russia, Australia, China, and India. The production was 167,58 EJ. There is coal for 131 years approximately. The countries that generate more energy thanks to Coal are in Asia Pacific, especially China, that is 50% of the global production. The consumption was 160,1 EJ.
Coal extraction in Spain:55% is obtained from open mines and 45% from underground mines.Open mines are cheaper but the impact on the surroundings is higher: territory lost, aquifer contamination, etc. Spain has approximately 200 thermal power plants with a total power of 27.000MW. Coal applications ºIndustrial boilers for heat generation. ºThermal power plants for electricity generation. ºCooking coal for steel industry. ºObtention of other fuels through coal liquation and gasification. To design coal burning processes, you must consider:ºCoal composition.ºCoal heating value.ºIf the combustion is complete (call carbon is converted to CO2) or incomplete (Some CO is formed).ºThe amount of air used. ºVolume & composition of flue gases.ºTheoretical&real combustion temperatures.
Pi =Lower Heating Value, can be calculated in kcal/kg from the mass fraction of carbon, hydrogen, and sulphur. Pi=8100Gc+28700Gh+2500Gs
 Combustión de carbón:ºCO2: Atmósfera.ºSO2: Tratamiento( Vía seca e ir al vertedero controlado o se aprovecha para yeso/H2SO4 o Vía húmeda e ir al vertedero controlado o aprovechar en yeso/H2SO4) º Partículas volátiles captar con filtros y vertedero controlado  ºCenizas al vertedero controlado
2 types of combustion chambers:Fixed bed: Coal is situated on fixed or mobile grill.ºAir circulates through coal’s bed.ºA high excess of air is needed.Lºower efficiencies due to the lack of mixing between coal and air.Fluidized bed: Pulverized coal is mixed and impulsed by air.ºBetter efficiencies due to the better mixing between reactants.ºNeeds lower excess of air and the temperature obtained is higher.

Coal gasification: Is an incomplete combustion to obtain combustible gases. It consists of the addition of extra hydrogen to coal in order to obtain a gas mixture with H/C rations bigger than the 0,6-0,8 typical value of coal. The process has kinetic, thermodynamic, and thermo-physical interactions.
Clean coal technology: In addition to syngas, a mixture of CO and H2 at different ratios can be used to obtain synthetic natural gas (SNG), methanol and urea (CO(NH2)2).Urea is the precursor of different organic compounds and can be used to synthetize a wide range of chemicals.Lurgi gasifier: Can be used to obtain synthetic natural gas from coal.Underground coal gasification: Is a process that converts coal into gases carried out in non-mined seams. A current of oxidizing agent is injected underground and the formed gases are obtained on surface through a drilled well. Licuación del carbón Es la conversión del carbón en un combustible líquido, mezcla de hidrocarburos. Esta técnica tiene la ventaja de convertir carbón sólido en combustibles menos contaminantes y en productos fácilmente transportables. El coste de los productos es alto, se prevé que vaya aumentando con el agotamiento del petróleo. La licuación de carbón puede ser:Licuación indirecta ºGasificar el carbón (C + O2 (déficit)  CO)º Obtener H2 con catalizadores (CO+H2O  H2+CO2)º Eliminar gases ácidos (CO2, SH2, SCO…) con absorciones de K2CO3.º Realizar la síntesis de Fisher-Tropsch (CO + H2  HC) con catalizadores de Fe a 220- 320ºC, 20-25 atm. Mezclas de hidrocarburos resultantes son gasolinas, fueloil, gasoil…º Separar con destilación fraccionada.ºBajo rendimiento del 36-55% y elevado coste, pero productos a la carta. Importante aumentar el contenido en hidrógeno del carbón.Licuación directa: Es necesario que se realice la ruptura (“cracking”) de muchas moléculas que forman el carbón en fracciones de peso molecular más pequeñas. Esto se consigue por pirólisis o por hidrogenación.ºPirólisis: calentar el carbón en ausencia de aire maximizando la producción de hidrocarburos líquidos rápidamente a T↑. Rend: 60 – 70%.ºHidrogenación: Se inicia con pirólisis y cracking a 430-470ºC, rompiendo enlaces C-C y C-O, formándose gases, líquidos y radicales libres. A continuación, se hace reaccionar con el solvente “Tetralin”, que da el hidrógeno adicional según: C10H12  C10H8 + 4H+ + 4e-. El rendimiento es del 60-75 %.Environmental impact in coal use: Coal power plants produce huge quantities of residues in gaseous, liquid, or solid phase: ºCO2 = Greenhouse effect = Earth temperature increase. ºSulphur = Inversions needed in desulfurization of flue gases.ºSolid particles (PM10 and PM2.5) released to the atmosphere.When Spain entered in the EU (1985), the legislation was adapted to EU standards: UE directive 88/609: Established limits to emission of contaminants generated in combustion facilities.
 R.D nº 646/1991: Is the application of the EU directive in Spain and establishes the global limits for the existing combustion facilities and limits for new installations. Economic cost of coal utilization:Extraction cost: Is the mining cost. They are higher in subterranean mines compared to open mines, and it depends on the depth and the extractive techniques. Using camber and pillars it has a yield of 60% and of long front has a yield of 60-90%.Preparation cost: It includes milling to separate coal and rocks. It can also include the cleaning of the coal using different techniques. In order to fulfil the quality and environmental requirements in the destination country. This step can suppose a weight loss of around 50% between the mined and the exported coal. Transportation cost: It includes the transportation between the mine and the harbour (truck or train). The maritime transportation. The transportation between the discharge harbour and the power plant.
Present situation of coal sector in Spain. Key factors:The sector has decreased activity from 45.000 employers to 3.126.70% of coal used in Spain is imported from Colombia, Indonesia, Russia, SA. Law 2010/787/UE says that if a company receives subsidies, it should finish its mining activity at 31/12/2018, the companies working on 2019 must return subventions received.
Is coal a solution? ºIt has the largest reserves of all fossil fuels. It is expected to last for more than 150 years.ºEvery year more energy is needed (Higher EROI) because deeper depths must be reaches and less rich deposits exploitedº Open pit mines have a much greater impact on the environment.º India has increased its consumption exponentially.º It is estimated that the peak of oil will occur in 2030.
Coal limitationsº Limitations to its use: Currently only electricity generation. Coal liquification and pyrolysis are not of great interestº Limitations to its extraction: The extraction of coal is dying because of the lack of diesel, mining and transportation need diesel.

Natural gas composition and properties:• Organic origin: Formed from vegetables, animals and microorganisms that were covered by sediments which produced a temperature and pressure increase that breaks the bonds in the organic matter.• Its main component is methane and minor proportions of heavier gases such as propane and butane.• The higher the temperature the higher the proportion of natural gas compared to petrol (Thermogenic origin).• If the reservoir is located at less profundity, organic matter decomposition is carried by microorganisms (Biogenic origin).• Natural gas commonly coexists with petrol.• Can contain impurities (N2, CO2, H2S, He, Ar, H20) that must be eliminated.Temperatura de saturación del GNL es de -162ºC por lo que se demandan materiales criogénicos para su transporte por vía marítima (licuado)En BCN hay GN mediante ENAGAS y parte se usa en la depuradora (CH4, CO2, H2). Hidrógeno es el combustible de mayor poder calorífico. El “índice de Wobbe” (en MJ/m3N) caracteriza la capacidad calorífica del gas. Se define como W=PCS/raíz(d), donde PCS es el poder calorífico superior y d la densidad relativa respecto al aire.
Purification treatments:• Desulfurization: To avoid corrosion problems in equipment and pipping. It is achieved via chemical absorption of CO2 and H2S in amine solutions and potassium carbonate.• Water elimination via adsorption, activated alumina or molecular techniques.• Liquation at low temperatures (cryogenic separation) to separate N2.• Hydrocarbons are separated in a process that cools and condensates the heavier fractions, Linde-Hampson process.• The condensation temperature of natural gas is -162ºC, at atmospheric pressure so cryogenic equipment is needed. The countries that have more reserves of natural gas are middle east, and CIS. The production of NG in 2021 was 145,33 EJ and the consumption was 145,35 EJ.
In Spain the production of NG is in Andalucia because the deposits in Vizcaya and Huesca are already depleted, but they might be used as reservoirs. 99% of the NG used in Spain is imported from other countries.
Inland gas ducts: Used for distances of around 3.500-4.500km.Design pressure above 16 bar.• Gas velocity around 10 m/s.• Active protection: Cathodic protection to avoid corrosion problems.• Passive protection: External polyethylene coating.• The capacity depends on the pressure difference and the diameter of the duct.• When distance is bigger than 200km you need a pumping station to recover the pressure needed for transport.• You also need a cooling system to protect the duct in the compression step (we are working in adiabatic conditions).
Submarine gas ducts: The optimum distance is around 2.000km.For longer distances, it is better to transport liquid NG in LNG carriers and convert it into gas once in the destination country.
Nabucco was cancelled thanks to USA and the Syria war.
A process is Cryogenic when TLiquefaction plants: Volume reduction to increase the amount of energy transported. You need previous treatments: o Acids cases elimination (CO2, Sulphur compounds): Mixing the gas counter current with an amine solution.o Water elimination via condensation.o Active carbon filters to eliminate other minor impurities.• The liquefaction process are cryogenic cycles of several steps in which other gases are obtained according to its molecular weight: propane, ethylene and methane.
LNG carrier: If the distance is bigger than 4.000km transportation is done at sea.• Very specialized transport and condensation temperature of -162ºC must be maintained during all the tripl.• They use the boil-off technique: The ships use and burns their own natural gas that they are transporting to obtain energy. This is because some LNG vaporizes and cannot be liquefied again and instead of releasing it to the environment, they use it.• They must be well isolated, using a sandwich system with 3 layers:o Membrane contention system: INVAR.o Isolating material: Wooden boxes filled with perlite.o Another layer made of INVAR or triplex materials.• The tanks are created with INVAR, an alloy of iron and nickel (36%). Because as the GNL must be on really low temperatures (-160ºC), this will destroy the iron, so it is highly protected.• When a gas tank is finished to build, it is cleaned with N2 to remove all the humidity and specially oxygen, because if there’s oxygen and natural gas, it could produce an accident. After that, the tank is filled with liquated N2 to cool the tank.• Capacity of between 100.000 and 200.000 m3 depending on the model.

Gasification plants:• Facilities located on harbours where the LNG carriers discharge its load.• LNG is discharged, stored, gasified, and sent to the customers.• Regasification is achieved using sea water, as its temperature is enough to fulfil the process requirements.• After gasification NG is injected to the national pipping system.
Storage tanks parts:• External concrete tank.• Inner layer of stainless steel as a layer between the concrete tank and the interior steel with 9% Ni layer.• Between both, there is an isolating layer filled with perlite or other materials.• Capacity is between 50.000-150.000m3 and discharge capacity 12.000m3/h
Cryogenic materials:• Metals at very low temperatures are fragile.• You can use aluminium allows or Fe/Ni allows with a minimum of Ni of 9%.
Underground storage of natural gas:• Overall capacity of the gasification plants installations is of several days.• In order to guarantee enough supply, underground storage facilities are built.• It is achieved refilling exhausted natural deposits.
Distribution lines:• Red de baja presión (P16 bar) para uso de transporte usando material base acero con coatings de polietileno, alquitrán…
Materials in pipes are, Steel, polyethylene, cast iron and cooper.High pressure pipes must be protected from corrosion with polyethylene layers, or paint.
ENAGAS is the technical manager of Spain, and it controls the transport pipe systems and the gasification plants, all the infrastructure.
For petrol  CLH (now EXOLUM) regulates the hydrocarbons market in Spain.
For natural gas  ENAGAS regulates the transport pipe system and gasification plants.
Natural gas uses are: Primarily for industry (66%), domestic use (26,5%) and commercial.
Natural gas has a LHV = 35.883 kJ/m3, similar to methane and a heat of vaporization of 510,83 kJ/(kg·K).
Applications of Natural Gas:• As heat, NG can be burned in boilers.• As mechanical energy in endothermic engines.• As electricity. In thermoelectric cycles (gas turbines).• As a refrigerator in Rankine cycles, NG is converted to mechanical energy to move a compressor.• In cogeneration as a source to produce both electricity and heat.• As a raw material for the chemical industry.• As electricity in a fuel cell.
ACTUALIDAD: generación de energía mecánica/eléctrica mediante el uso de turbinas de gas accionadas con G.N. Se utiliza en las centrales de producción de electricidad.• Turbina de gas con regenerador: Aire (fluido) se comprime en un compresor, pasa a la cámara de combustión se combustiona con el GN entrado. El resultante en forma de humos acciona la turbina; produciendo energía mecánica o eléctrica mediante un generador. Además, la turbina da energía mecánica (eje) para mantener el compresor.• Las centrales de ciclo combinado aprovechan el calor residual del aire a la salida de la turbina para producir H2O (v) en un intercambiador de calor (Generador de Vapor). Este vapor, mediante un ciclo de Rankine, produce trabajo mecánico al expansionarse en una turbina de vapor que puede accionar un alternador para producir energía eléctrica.• Trigeneración eléctrica, térmica y frigorífica usando un ciclo de Bryton, intercambiador de calor y ciclo de absorción. Energía térmica (intercambiador de calor), eléctrica (c.Bryton), y frigorífica (ciclo de absorción). Y=We+Qt+Qf/m·PCNG

Why it is not a long-term solution? It has important limitations:• It has fewer applications than oil.• Its transportation is complicated and involves a large energy cost.• It is more dangerous than oil.• Peak gas will happen between 2022-2027 but if NG is used as a substitute of other fuels, it will occur much earlier.Europe has reached its peak consumption and is currently dependent on LNG imports from the Middle East, USA, Australia, and the prices are 3 times higher than what they were paying for Russian gas.

El átomo está formado por p+, n, e-. Por un núcleo (protones y neutrones) con carga positiva y una nube de electrones con carga negativa. Nº atómico (Z) = n · e-= n · p+ átomo neutro Nº másico (A), protones + neutrones = nucleones En general, mayor número de neutrones, más inestable es el átomo. Como mayor es el átomo, más neutrones tiene.Isótopos = Núcleos con mismo Z (nº atómico) y diferente A (nº másico). Núcleos isobáricos = Misma A y diferente Z. Inestabilidad= Determinada por la semivida.La unidad usada es el electrón volt (eV), que es la cantidad de energía cinética ganada por un único electrón acelerando del resto a través de una diferencia de potencial de 1 volt en vacío. 1eV = 1,6·10-19JLa masa de un núcleo XA que denominamos m (A, Z) es más pequeña que la suma de las masas de sus protones y neutrones libres. Esta diferencia es el “defecto másico”: Δ(𝐴, 𝑍) = 𝑍 · 𝑚𝑝 + (𝐴 − 𝑍) · 𝑚𝑛 − 𝑚𝑛(𝐴, 𝑍) ,   ∑▒m_(p,n,e)  〖≠m〗_(x_Z^A )
Hidrógeno: Protón  H_1^1,n=0,p=1,e^-=1.Abundancia=99,985%Deuterio (D)  H_1^2,n=1,p=1,e^-=1.Abundancia=0,0156%Tritio (T)  H_1^3,n=2,p=1,e^-=1.  T=12,32 años. Reacción de fusión  H_1^2+H_1^3-→〖He〗_2^4+n
Uranio u_92^232-→T=68,9 años.Sintético. u_92^233-→T=159.200 años.Sintético. u_92^234-→T=245.500 años.Abundancia=0,0054%. u_92^235-→T=7,038·10^8  años.Abundancia=0,7204%. u_92^236-→T=?.Sintético. u_92^237-→T=4,51·10^9 años.Abundancia=99,2742%
Energía de enlace del núcleo: Es la manifestación de las fuerzas del núcleo que mantienen el núcleo unido.  . Las interacciones entre protones son repulsivas. Si un núcleo es inestable, tenderá a la estabilidad a través de procesos de desintegración, se llaman núcleos radioactivos.
Fisión: El núcleo pesado A3 es roto en núcleos más ligeros con un número másico intermedio A2  Fusión: Núcleos ligeros A1 se convierten en núcleos pesados A2. La masa de un protón no es la misma que la masa de un protón y un electrón. He es un subproducto típico de las reacciones nucleares.  La reacción de fisión es fácil de empezar, usando una masa crítica. Tú tienes u235 y le añades una pequeña cantidad de u236, pero es muy difícil de mantener en el tiempo. Es por eso por lo que industrialmente se usa la fisión.
Las reacciones nucleares pueden emitir 4 tipos de radiaciones:Radiación alfa  Se para con una hoja de papel.Radiación beta  Lámina de aluminioRadiación gamma / X  Placa de plomoRadiación neutrónica  Se para con un bloque de agua u hormigón
La ley de desintegración radiactiva indica la evolución del número de núcleos radiactivos presentes en una muestra en función del tiempo.  Cada núcleo radioactivo tiene una probabilidad de desintegración, que es independiente al número de núcleos y tiempo y se llama constante de deterioro λ. dN/Ndt=-λ N=N_0·e^(-λt) Media-vida de un átomo  Tiempo requerido para que una cantidad se reduzca a la mitad de su valor inicial.
Activity (A)=dN/dt=λN   Number of decays per time [Bq]  [Ci]Periodo radioactivo T,tiempo que tarda un núcleo en reducirse 1/2=0,693/λ Reacción de fisión: Ocurre cuando un átomo con un número atómico grande recibe un neutrón y se rompe en átomos más pequeño. La energía liberada durante la reacción (200MeV) es a suma de la energía liberada en distintos procesos: Uranio usado, tiene dos tipos de núcleos radioactivos: Núcleos físiles: Es aquel que reacciona con neutrones de cualquier energía. u235. (0,7%)Núcleo fértil (o fisionable): Reacciona únicamente con neutrones de alta energía. u238 (99,3%)Normalmente los núcleos fértiles se destinan a la proliferación nuclear (crear armas nucleares). En reactores de uranio enriquecido el uranio 238 se usa como elemento estructural y el 235 para generar energía.                                      Partes de un reactor nuclear:Combustible: Su misión es fisionarse para obtener energía. (u238 a u235)Moderador: Se encarga de convertir los n de reacción a n térmicos. Se usa agua, deuterio, grafito. Ha de ralentizar los neutrones, pero no detenerlos.Barras de control: Se intercalan entre las unidades de combustible y sirven para capturar completamente neutrones. Se usa cadmio, boro e indio, porque forman un isótopo estable. Sirven para controlar el reactor, ponerlo en marcha, apagarlo, etc.Reflector: Es una especie de espejo de neutrones.Escudo biológico: Se usa hormigón como última defensa para capturar neutrones y evitar la radiación.
Calor residual: Es el calor que se genera de los productos de fisión y durante la operación del reactor. Si el reactor no está refrigerado, esta acumulación puede fundir el reactor y causar consecuencias. Se usa agua ligera, agua pesada (D2O).

Capacidad de regeneración: El fuel U238 Y Th232 pueden producir en el reactor elementos fisibles como Pu239 y U233. El primero se usa como arma nuclear.
Acuerdo de no-proliferación nuclear: Solo se puede hacer fisión usando neutrones térmicos y uranio enriquecido.
El año 2013 la producción mundial de energía nuclear bajó ya que los japoneses cerraron todas sus centrales por el accidente de Fukushima.
Sodio líquido tiene alta capacidad térmica y baja captura de neutrones. Se usa para reactores de neutrones rápidos.FBR: Fast neutron breeder reactor LWR (Light Water Reactor): Incluye el BWR + PWR.LMR: Light Metal Reactor. Sodium cooler reactors. El calor se extrae del núcleo con sodio primario y se transfiere a un segundo y no-radioactivo ciclo de sodio, que sirve como fuente de calor para el generador de vapor que calienta el agua en el ciclo terciario para dar energía a la turbina. CANDU reactor: Canada Deuterium Uranium reactor. Es moderado y enfriado usando agua pesada.La eficiencia global es del 32-34%, el combustible dura 1-1,5 años.El presurizador mantiene la presión a 150 bar, para que sea líquida

Proceso Después de quemar el combustible, el calor se transmite a un refrigerante (agua) que mueve una turbina y produce electricidad en un ciclo de Rankine. La refrigeración se hace en un ciclo secundario usando agua fresca de un río o agua de mar. El combustible usado es un residuo de alta actividad que se almacena EN piscinas mientras se enfría, se transfiere a instalaciones especiales.
Ciclo del combustible nuclear: MineríaºEl uranio es relativamente abundante y tiene más de 150 variedades.ºEl mineral más común son óxidos de uranio con composición variable.ºTambién hay uranio en el agua de mar, carbón y fosfatos.ºLos ricos tienen 1-4% pureza, los medianos 0,10-0,5% y pobres 0,01%. ºLos países que más uranio extraen son Kazakstán y Canadá.ºAún queda para 120 años.
PurificaciónºEl mineral se somete a procesos de trituración, tamizado (sieving), separación por gravedad y lixiviación (leaching). ºEl producto que se obtiene se llama pastel amarillo U3O8 ºEl dióxido de uranio se obtiene a partir de reducción con hidrógeno  
EnriquecimientoºEn uranio natural hay 0,7% de uranio fisible U235 y 99,3% de uranio fértil U238.ºPara usar el uranio en PWR y BWR hay que enriquecerlo.ºSe elimina parte de U238 para incrementar la fracción de uranio fisible.º Hay 3 rutas de enriquecimiento, pero todas son en fase vapor.º El compuesto UF6 sublima a 56ºC y entonces el enriquecimiento ocurre. Después se transforma en UO2 que se usa como fuel.
Los 3 métodos de enriquecimiento son:Difusión gaseosa: UF6 gas atraviesa una membrana porosa comprimida de 10-4mm de diámetro. El isótopo ligero U235 F6 atraviesa la membrana a una velocidad superior al isótopo pesado U238 F6 entonces se aumenta ligeramente la concentración del primero. Si esto se repite cientos de veces se obtiene el uranio enriquecido.Centrifugación:UF6 está ubicado dentro de cilindros que rotan a muy altas velocidades y ambas moléculas se someten a fuerzas centrifugas que son función de sus masas. Este proceso se repite hasta que se consigue la concentración deseada.Enriquecimiento láser:Un láser ioniza U235 y luego se atrae usando un imán. Aún no está operativoEl 90% del uranio enriquecido se usa para hacer armas nucleares.
Fabricación de elementos combustibles: En los reactores LWR el combustible está agrupado en 157 elementos de varas 17×17 hechas de una aleación zirconio/acero que contienen UO2. Cada vara tiene óxido de uranio sinterizado.
Combustible dentro del núcleo del reactor:El combustible se expone a un flujo de neutrones que lo quema y genera elementos radioactivos y calor.La fisión empieza con la captura del neutrón libre y otros componentes para conseguir los protones energéticos deseados.La quema de uranio se mide en MW/tonU y el combustible dura unos 3 años, aunque se cambia cada 1,5.Para empezar la fisión de núcleos pesados se necesita una energía de 7-8 MeV para superar la fuerza nuclear que mantiene el núcleo en forma esférica. Esta esfera se deforma en forma de cacahuete y poco a poco se van separando ya que ambas son positivas.Cuando se llega a una distancia crítica, se separan y se forman dos fragmentos fisibles que se alejan con altas energías.

Final del ciclo de combustible:El combustible usado primero se almacena en una piscina de enfriamiento para eliminar el calor residual, generado por desintegración de productos de fisión.El combustible usado es un High Level Waste (HLW) y se puede eliminar usando un ciclo abierto o enriquecerse en un circuito cerrado. En circuito abierto el combustible enfriado se elimina en la superficie, otras piscinas o en el exterior, también en depósitos subterráneos.El circuito cerrado consiste en reutilizarlo para recuperar el U235 residual y el Pu239 generado. Con el Pu239 se aumenta la proliferación de armas nucleares, es muy controvertido.
Limitaciones de la energía de fisión:Tiene una eficiencia económica pequeña, ya que su instalación y su inversión inicial son muy elevados. Los costes operativos son bajos, pero hay que investir mucho en seguridad.Produce únicamente electricidad.No hay mucho Uranio según la IEA.Teóricamente los reactores de 4ta generación (neutrones rápidos), serán mejores porque hay mucho Torio y el residuo generado es menor.

Nuclear fusion: Is the union of two light nuclei to form a bigger atom in an exothermic reaction. It is a natural process that occurs in the stars. To produce these reactions the electrostatic repulsion forces that keep those atoms separated must be overcome. This is very difficult because the repulsive forces are really strong, the energy is equivalent to 150.000.00ºC, it exists in plasma state. As there aren’t materials capable of resisting this temperature, a magnetic field is used. 
Los dos métodos de confinar el plasma es usando láseres (confinamiento inercial) o con imanes y vacío, el objetivo es evitar que el plasma toque las paredes.
 There’s no fuel scarcity because deuterium can be obtained from sea water, it is a stable hydrogen isotope with an abundancy of 0,01456%.
H_1^2+H_1^2-→〖He〗_2^3+n_0^1   (3,26 MeV)
H_1^2+H_1^2-→〖He〗_2^3+p_1^1   (4,04 MeV)
H_1^2+H_1^3-→〖He〗_2^4+n_0^1   (17,6 MeV)
Tritium can be obtained through a fission reaction from lithium using the neutrons produced in the fusion reaction:
〖Li〗_3^6+n_0^1-→〖He〗_2^4+H_1^3
〖Li〗_3^7+n_0^1-→〖He〗_2^4+H_1^3+n_0^1
Q factor= Ratio between the produced energy divided by the amount of energy needed to maintain the fusion process in steady state. To be viable it should have Q>10, now 1.
Que determina si un plasma es correcto, si la fusión ha funcionado.
Q=(Energía fusión)/(Energía necesaria para mantener la fusión)>10

Lawson criteria: The optimum condition to form plasma needed in fusion must be bigger than 3·1028K m-3 s-2 and it depends on 3 factors:ºPlasma temperature.ºPlasma density (number of changed particles per volume).ºPeriod of time plasma remains in steady state.
ρ·T·t=màximo (>3·10^28)
La fusión D+T consiste en 2 fases:
〖Li〗^7+n_0^’-→〖T+He〗_2^4
D+T-→〖T+He〗_2^4+n_0^’
En 2006 los japoneses consiguieron mantener la fusión durante 28,6 segundos.
Inertial confinement: Unos láseres impactaran en la esfera (cápsula de combustible deuterio + tritio congelado para tener más densidad, hohlraun con una rugosidad superficial de menos de 1 micra y con alto número atómico Z) desde todas las direcciones para generar fuerzas simétricas y la esfera se dejará caer, antes de que haya caído al suelo se tiene que haber fusionado. Los láseres también aumentan la densidad ya que se comprime a altas presiones con los rayos láser o iónicos. Como aumenta la temperatura y también la presión, la fusión es posible, ya que debido al medio altamente denso las partículas no pueden escapar. La energía de los rayos ha de ser superior que 10 kJ por nanosegundo.

FASES del CONFINAMIENTO INERCIAL El calentamiento del blanco provoca la separación del material de la superficie y, por consiguiente, la formación de una corona de plasma a su alrededor, donde habrá electrones energéticos y radiación.
Como consecuencia del calor, la superficie de plasma comenzará a evaporarse hacia el exterior. A continuación, la esfera se comprimirá. Como las energías que intervienen son muy grandes, el proceso de evaporación es muy brusco y la compresión de la esfera lo es también. Como consecuencia se produce una implosión que comprime y calienta el combustible del interior hasta los valores necesarios para encender el plasma. En esta etapa es cuando comienza el confinamiento inercial.
Las partículas alfa producidas por la fusión deberían aumentar la temperatura del combustible aún más. Si la densidad es suficientemente alta, la energía de las partículas alfa queda atrapada por el combustible que rodea al núcleo, y lo calienta hasta encenderse también. Se ha llegado al punto de ignición, aproximadamente 100.000.000ºC y densidad 20 veces superior a la del plomo. El calor se expande en una onda de quemado hacia fuera disminuyendo su densidad y apagándola. En este momento termina el confinamiento inercial. Funcionamiento: El área principal la forma una cámara grande al vacío, donde se introduce la microesfera. Se la bombardea con una serie de haces, de láser o de partículas energéticas produciendo la implosión del blanco seguida de una mini explosión termonuclear. Las bombas de vacío retirarán los gases y los desechos antes de que una nueva microesfera sea introducida en la cámara. Aproximadamente se pueden hacer entre una y diez inyecciones por segundo, de forma que la energía liberada puede ser recolectada de forma continua. El calor producido en las paredes de la cámara a causa de los neutrones resultantes de las reacciones y de las partículas alfa, que escapan se extrae con un fluido refrigerador en un secundario que es turbinado para generar electricidad. Magnetic confinement: El plasma (un gas totalmente ionizado) se calienta a altas temperaturas haciéndole pasar una alta corriente eléctrica (Efecto Joule) y confinándolo en un sistema adecuado con imanes superconductores que evitan que haya contacto entre el plasma y muros del reactor. El plasma se confina de manera toroidal, en un diseño Tokamak4 formas de calentar el plasma (150.000.000ºC) Calentamiento óhmico: Perdida de calor en un conductor. Tenemos un súper núcleo de cobre, que es el tubo que pasa por dentro del toroide de la imagen superior. Pasan 15MA y la disipación térmica que tiene este núcleo será la que proporcione la corriente. Efecto Joule.Radiofrecuencia: Distintas frecuencias son necesarias para cada partícula, 200 GHz para los electrones y 70 MHz para los iones).Inyección de partículas neutras: Inyectaremos partículas neutras (Helio, por ejemplo), le damos una carga y lo aceleramos, entramos un gas neutro en perpendicular y esperamos a que alguna partícula cargada choque con la no cargada, eso se envía al reactor y también se quiere a que alguna de ellas choque con alguna partícula dentro del reactor, aumentando la temperatura por choque inelástico.Energía de los productos de reacción: El Helio que se forma se queda cierto tiempo en el reactor, perdiendo parte de su energía cinética y térmica. Breeding blanket: Consiste en una serie de módulos que cubren el interior del reactor de fusión y que pueden aguantar una elevada carga de calor y flujo de neutrones. Sirve para asegurar la autosuficiencia del tritio en el reactor y para maximizar la eficiencia de la planta de energía. Divertor: Los productos de reacción son recogidos en el divertor y siguen un ciclo cerrado. Es su energía térmica la que se aprovecha. El divertor es uno de los componentes clave de los reactores tipo Tokamak. Se sitúa al fondo del toroide, dentro la cámara de vacío. Su función es extraer calor, He y cenizas (los dos productos de la reacción) actuando como un gran tubo de escape. Está compuesto de dos partes: la estructura de soporte, de acero inoxidable, y los componentes en contacto con el plasma que están hechos de tungsteno, un material altamente refractario. El divertor debe aguantar temperaturas de 3000ºC durante largos periodos de tiempo. Es esta temperatura en el divertor la que se aprovecha en un circuito secundario para generar electricidad. Generación de residuos nucleares: Con excepción del tritio, no hay elementos radioactivos dentro del reactor, hay menos de 1g de fuel por segundo en el reactor y si no hay fuel se para. Algunos isótopos radioactivos se pueden formar con el impacto de un neutrón con la estructura, pero se eliminan con el divertor ya que es ceniza. E=σ(Te^4 (150.000.000ºC)-Tr^4 (4 Kelvin)Limitaciones de la fusiónSe necesitan muchos recursos y de difícil obtención.El EROI es muy bajo actualmente.Quizás llega demasiado tarde y es una falsa esperanza.