Active and Passive Solar Energy

Passive vs. Active Solar Power

• Passive solar power uses building design and materials to capture and store sunlight without mechanical systems.
• Active solar power uses mechanical and electrical equipment to convert sunlight into usable energy.
• Examples of active solar power include solar photovoltaic (PV) panels and solar thermal systems.
• Passive methods include south-facing windows, thermal mass for heat storage, and natural ventilation.

Uses of Active and Passive Solar Power

• Active solar power is used to generate electricity or heat water.
• Passive solar power is used to heat and cool buildings through design elements that absorb or reflect sunlight.

Advantages of Solar Thermal and Photovoltaic Systems

• Solar thermal electric generation can produce electricity even without direct sunlight using thermal storage systems.
• It is suitable for large-scale energy generation.
• Photovoltaic solar cells provide a clean, renewable, and scalable energy source adaptable for residential or commercial use.
• PV panels can be installed on rooftops, reducing land usage.

Definition of Biomass

• Biomass is organic material from plants and animals used as an energy source.
• Examples of biomass include wood, agricultural residues, and animal waste.

Biomass as Indirect Solar Energy

• Biomass is considered an indirect form of solar energy because plants use sunlight for photosynthesis, storing solar energy in their biomass.

Advantages and Disadvantages of Biomass Energy

• Biomass is renewable, reduces waste, and can be carbon-neutral if managed properly.
• It can be used for heating and electricity.
• Disadvantages include deforestation if not managed sustainably.
• Burning biomass releases greenhouse gases and requires large land areas.

Optimum Locations for Wind and Hydropower

• Coastal regions, mountain passes, and the Great Plains are ideal for wind energy.
• Areas with large water bodies or steep rivers, like the Pacific Northwest, Scandinavia, and Canada, suit hydropower.

Potential of Wind vs. Hydropower

• Wind energy has vast potential, especially in coastal areas, but is intermittent.
• Hydropower offers more consistent energy output, but relies on water resources and can have environmental impacts.

Solar Energy's Direct and Indirect Results

• Uneven heating of the Earth's surface by the sun causes wind energy.
• Photosynthesis, using solar energy, results in biomass.

Energy Conservation vs. Energy Efficiency

• Energy conservation reduces energy consumption by using less energy.
• Energy efficiency uses technology or methods that require less energy to perform the same task.

Cogeneration Defined

• Cogeneration is the simultaneous production of electricity and useful heat from the same energy source, improving efficiency.

Example of a Large-Scale Cogeneration System

• A power plant uses natural gas to generate electricity and captures waste heat for district heating.

Carbon Dioxide Levels and Biomass

• Biomass can be carbon-neutral if the carbon dioxide emitted is offset by the carbon absorbed during growth.
• Unsustainable management can lead to a net increase in CO₂ emissions.

Great Plains as the "Saudi Arabia of Wind Power"

• The Great Plains states have ideal conditions for wind energy production with consistent winds and vast land areas.

Energy from a Small River vs. Vast Oceans

• Energy from a small, steep river is easier to obtain due to concentrated and predictable water flow.
• Ocean currents are dispersed, unpredictable, and influenced by many factors.

Pros and Cons of Geothermal Energy

• Geothermal energy is reliable, renewable, produces minimal greenhouse gases, and provides base-load power.
• It is location-specific, has high initial costs, and may cause land subsidence or release harmful gases.

Renewable and Nonrenewable Energy Resources

• Nonrenewable resources exist in a fixed amount and cannot be easily replaced.
• Renewable resources can be replenished naturally at or near the rate of consumption.

Global Energy Consumption

• Energy resource use is unevenly distributed between developed and developing countries.
• Fossil fuels are the most widely used energy sources globally.
• Developing countries increase their reliance on fossil fuels as they industrialize.
• Increased industrialization raises the demand for energy.
• Availability, price, and government regulations influence energy source selection and usage.

Fuel Types and Uses

• Wood is commonly used as fuel, especially in less developed countries due to its accessibility.
• Peat is partially decomposed organic material that can be burned for fuel.
• Lignite, bituminous, and anthracite are three types of coal used for fuel.
• Heat, pressure, and burial depth affect the development and qualities of coal types.

Fossil Fuels

• Natural gas, mostly methane, is the cleanest fossil fuel.
• Crude oil can be recovered from tar sands, a mix of clay, sand, water, and bitumen.
• Fossil fuels can be made into specific fuel types for specialized uses, such as in motor vehicles. Cogeneration uses a fuel source to generate both heat and electricity.

Distribution of Natural Energy Resources

• The global distribution of natural energy resources depends on a region's geological history. These resources are not uniformly distributed.

Fossil Fuels

• Fossil fuel combustion is a chemical reaction between fuel and oxygen, yielding carbon dioxide, water, and energy.
• Burning fossil fuels generates heat, turns water into steam, and drives a turbine to generate electricity.

Methods to Extract Fossil Fuels

• Mining techniques extract coal through surface and subsurface methods.
• Drilling and fracking extract oil and natural gas.
• Fracking can cause groundwater contamination and release volatile organic compounds (VOCs).

Nuclear Power

• Nuclear power is generated through fission, where Uranium-235 atoms split into smaller parts after being struck by a neutron.
• Nuclear fission releases heat, which is used to generate steam, power a turbine, and generate electricity.
• Radioactivity occurs when a radioactive isotope's nucleus loses energy by emitting radiation.
• Uranium-235 remains radioactive for a long time, causing nuclear waste disposal issues.
• Nuclear power generation is a nonrenewable energy source. Considered a cleaner energy source but produces thermal pollution and hazardous solid waste.

Nuclear Accidents

• Accidents at Three Mile Island, Chernobyl, and Fukushima led to radiation releases.
• These releases have short and long-term environmental impacts.
• A radioactive element’s half-life can be used to calculate decay and radioactivity.

Energy from Biomass

• Burning biomass produces heat at a relatively low cost
• It also produces carbon dioxide, carbon monoxide, nitrogen oxides, particulates, and VOCs.
• Overharvesting trees for fuel causes deforestation.

Ethanol

• Ethanol can be used as a gasoline substitute.
• Burning ethanol does not introduce additional carbon into the atmosphere.
• Energy return on energy investment is low for ethanol.

Solar Energy

• Photovoltaic solar cells capture light energy from the sun and transform it directly into electrical energy, but usage is limited by sunlight availability.

Active Solar Energy

• Active solar energy systems use solar energy to heat liquid through mechanical and electrical equipment to collect and store energy from the sun.

Passive Solar Energy

• Passive solar energy systems absorb heat directly from the sun without mechanical and electrical equipment, so energy cannot be collected or stored. Concentrated solar power/solar thermal systems have low environmental impact and produce clean energy and can be expensive.
• Large solar electric energy farms can negatively impact desert ecosystems.

Hydroelectric Power

• Generation methods include dams built across rivers; water moves through the dam and turns a turbine. Turbines are placed directly in the flow of smaller rivers.
• Hydropower does not generate air pollution or waste, but construction of plants and dams can be expensive and alter river ecosystems, effect species migration and change sediment flow.
• Tidal power uses energy produced by tidal flow to turn a turbine.

Geothermal Energy

• Geothermal energy is obtained by using the heat stored in the interior of the earth to heat up water that is brought back to the surface as steam
• Steam is used to drive a turbine to spin an electric generator. Can be prohibitively expensive, is not accessible in many areas of the world, and can cause the release of toxic hydrogen sulfide.

Hydrogen Fuel Cell

• Hydrogen is used as fuel and combined with oxygen in the air to form water and release energy (electricity) in the process. Water is the byproduct (emission).
• These fuel cells have low environmental impact and produce no CO2 when the Hydrogen is produced from water.
• The technology is expensive, however, and energy is still needed to create the hydrogen gas.

Wind Energy

• Wind turbines use kinetic energy of moving air to spin a turbine
• Mechanical energy of the turbine is converted into electricity. Although clean and renewable, birds and bats may be killed flying into turbines and they may spoil the aesthetics of an area and need transmission lines.

Energy Conservation

• In-home conservation methods include adjusting the thermostat, conserving water, use of energy-efficient appliances, and conservation landscaping.
• Large-scale conservation methods include improving fuel economy of vehicles, using Battery Electric Vehicles (BEVs) and hybrid vehicles, increasing use of public transportation, and implementing green building designs.

Transformation of Energy

• All organisms transform energy, and energy is the capacity to do work.
• Living organisms use chemical energy.
• Energy conversions are the basis of life.

Energy Laws

• Systems are either closed or open.
• First Law states energy can be transferred and transformed but it can never be created nor destroyed.
• The Second Law states every energy transfer or transformation increases the entropy of the universe (e.g. creating heat).

Types of Energy

• Six types of energy are Radiant (light photons), Nuclear (contained in nuclear attraction between protons and neutrons), Chemical (Stored in the bonds between atoms in molecules), Mechanical (motion of objects), Thermal (heat energy in the movement of molecules), and Electrical (movement of electrons).

Transformation of Energy

• Solar energy converts to chemical energy through photosynthesis. This chemical energy becomes food that creates mechanical energy, the energy to move, think, and live. Waste heat gets released at each of these stages.

The Quality of Energy

• An energy source’s ability to do useful work.
• High Quality: (1) organized, (2) concentrated, (3) can perform useful work.
• Low Quality: (1) disorganized, (2) dispersed, (3) little ability to do useful work.

Examples of High and Low Quality Energy

• High quality includes electricity, the chemical energy stored in coal and gas, concentrated sunlight, nuclei of U-235, and concentrated heat.
• Low quality includes heat dispersed in the atmosphere or stored in an ocean.

Relative Energy Quality

• Very-high-temperature heat, concentrated sunlight, high-velocity wind, concentrated geothermal energy is very high. Normal sunlight, Moderate-velocity wind, High-velocity water flow have moderate energy quality. and Dispersed geothermal energy, Low-temperature heat Low have low energy quality.

Source of All Energy on Earth

• The sun
• The sun lights and warms the planet and supports photosynthesis where radiant energy converts to chemical by producers. Powers the cycling of matter and Drives climate and weather systems distributing heat and fresh water on earth

Energy to Earth

• Energy can be used to perform tasks. Very-high-temperature heat can be used for industrial processes and producing electricity to run electrical devices. Mechanical motion can be used to move vehicles and other things. Moderate-temperature heat can be used for space heating.
• Light and warms the planet; supports photosynthesis where radiant energy is converted into chemical energy by plants, protists and bacteria. Powers the cycling of matter and drives climate and weather systems distributing heat and fresh water on earth

Distribution of the Sun's Energy on Earth

• 34% of solar energy reflects back into space by atmosphere (albedo effect)
• 66% remains where it warms troposphere and land, evaporates and cycles water, and generates wind.
• 0.023% captured by producers for photosynthesis. Energy eventually transformed to heat and trapped by atmosphere “Natural Greenhouse Effect”

Energy Sources and Consumption

• Energy sources used to be local. Now shared worldwide where the source is fossil fuels (55.5% imported) and nuclear energy such as uranium mined then shipped (electricity even passes country to country).
• The consumption is different between developing and developed nations, where 20% of world’s population use 60% of the world’s energy sources (developed uses 8x’s more than developing).

Energy Consumption in the US

• Industries (production) use the most. Heating, cooling, and illuminating building is 1/3.

Fossil Fuels

• Combustible deposits in the Earth’s crust which include coal, oil (petroleum) and natural gas where composed of the remnants (fossils) of prehistoric organisms that existed millions of years ago. Considered to be are non-renewable resources

Fossil Fuel Formation

• 300 million years ago the earth had a mild climate. Vast swamps covered much of the land with dead plant material decayed slowly in the swamp environment include giant ferns, horsetails, and club mosses. Sediments accumulated over time. Heat, pressure, and time turned the plant material into carbon-rich rock (coal).
• When sediments deposited over microscopic plants heat, pressure and time turned them into hydrocarbons (oil). Natural gas then Formed the same way as oil, but at temperatures higher than 100 °C.

Coal

• Occurs in different grades which is based on variations in heat and pressure during burial (includes Lignite, Subbitumimous, Bituminous, and Anthracite). Most, if not all, coal deposits have been identified.

US Coal Supplies

• The US has 25% of world’s coal supplies. Known coal deposits could last 200 years (at present rate of consumption).

Types of Coal Mining

• Surface mining chosen if coal is within 30m of surface where mineral and energy resources are extracted near Earth’s surface by first removing the soil, subsoil, and overlying rock strata. Subsurface mining is the extraction of mineral and energy resources from deep underground deposits

Environmental Impacts of Mining Coal

• Surface Mining Control and Reclamation Act (1977) requires filling (reclaiming) of surface mines after mining (expensive!) and Reduces Acid Mine Drainage Requires permits and inspections of active coal mining sights and prohibits coal mining in sensitive areas.
• Other impacts are Mountaintop Removal filling valleys and streams with debris destroying thousands of acres of deciduous forest, one of the most land destructive techniques.

Environmental Impacts of Burning Coal

• Burning coal releases large quantities of CO2 into the atmosphere (greenhouse gas) and other pollutants such as Mercury, Sulfur oxides, and Nitrogen oxides causing acid precipitation.

Oil and Natural Gas

• Oil and gas provide 60% of world’s energy and 63% of US’s energy, and 23% provided by coal. Petroleum refining is the process of Numerous hydrocarbons present in crude oil (petroleum) separated based on boiling point. Natural gas contains far fewer hydrocarbons than crude oil: Methane, ethane, propane and butane

Oil and Natural Gas Distribution and Use

• There is an uneven distribution globally. More than half is located in the Middle East which includes Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, Syria, Yemen, and the United Arab Emirates. The US US uses 18-22 million barrels a day and our production is about 8 million. Canada, Mexico, Saudi Arabia, Iraq, Venezuela are US largest suppliers

Oil & Natural Gas Environmental Impacts

• Combustion causes increased carbon dioxide and pollutant emissions (nitrogen oxides/photochemical smog) and Natural gas is far cleaner burning than oil. Production impacts are land and habitat disturbances through transport via spills (especially in aquatic systems), Exxon Valdez hit a reef in Alaska (1989) and spilled 260,000 barrels of crude oil into sound
• In 2010 there was an Oil platform explosion opened seafloor gusher which released 4.9 million barrels over 87 days. Result BP to pay 18.7 billion in damages largest settlement in history.

Synfuel and Other Fossil Fuel Resources

• Synfuel includes liquid or gaseous fuel synthesized from coal and other naturally occurring sources, and used in place of oil or natural gas (includes Tar sands, Oil shales, Gas hydrates, Liquefied coal, and Coal gas).

Nuclear Power

• Nuclear fission is the nuclear energy released when atom split. Fusion is the nuclear energy released when atoms fused which have an enormous potential to release a vast amount of energy as primarily heat

Atoms and Radioactivity

• Radioactivity's Atomic mass = the sum of the protons and the neutrons in an atom. Atomic number = number of protons in an atom. Isotopes = the same (single) element that differ in their atomic mass.
• unstable isotopes are called radioisotopes and are said to be radioactive b/c they spontaneously release (emit) radiation (see radioactive decay) **The only radioisotope of hydrogen is tritium.

Atoms in the Nuclear Process

• Atomic mass is typically caused by greater number of neutrons where results in an isotope. Chemical behavior is identical to normal atom. Many are radioactive.

Nuclear Fission

• Using Uranium ore, a mineral used in conventional nuclear power plants, is nonrenewable resource present in limited amounts and found in sedimentary rocks found in the earths crust.

Nuclear Fuel Cycle

• Nuclear mines and mills turn U-235 enrichment where fabrications of fuel assembles creates spent fuel. This turns in the nuclear power plant using uranium tailings and depleted uranium tails factory creating low level wastes and high level wastes.

Producing Electricity from Nuclear Energy

• A typical nuclear power plant has four main parts: 1. the reactor core 2. steam generator 3. turbine and 4. condenser.
• Fission occurs in the reactor core and the heat that is produced is used to produce steam from liquid water in the steam generator. The turbine then uses the steam to generate electricity. The condenser then cools the steam converting it back into a liquid.

Renewable Energy and Conservation

• Direct Solar Energy varies with latitude, season, time of day, and cloud cover. System of putting the sun’s energy to use without requiring mechanical devices to distribute the collected heat. Certain design features can enhance passive solar energy’s heating potential and also utilizes passive solar energy to heat and cool homes where it Does not require pumps or fans and Can be added to existing homes.

Active Solar Energy Systems

• Systems of collecting and absorbing the sun’s energy, and using pumps or fans distribute the collected heat series of collection devices on roofs or in fields with a typically a black panel or plate where Used to heat water

Solar Thermal Electric Generation

• Solar Thermal Electric Generation is a means of producing electricity in which the sun’s energy is concentrated by mirrors or lenses to either heat a fluid filled pipe or drive a Stirling engine with little to no air pollution while not contributing to global warming or acid precipitation.

Photovoltaic Solar Cells

• These thin cells are treated with certain metals (phosphorus and boron) and silicon so that they generate electricity when they absorb solar energy which Converts sunlight directly into energy with no pollution and minimal maintenance used on any scale (lighted road signs and entire buildings) where they can be incorporated into building materials (roofing shingles, tile, and window glass)

Indirect Solar Energy

• Biomass is Plant materials used as fuel where Contains energy from sun via photosynthesizing plants which are Renewable when used no faster than it can be produced and can convert to biogas or liquids (as in Ethanol and methanol). Can reduce dependence on fossil fuels, often uses waste materials, and that trees are planted at same rate biomass is combusted, no net increase in atmospheric CO2). (Requires land, water and energy while leading to Deforestation, Desertification and Soil erosion.)

Direct Wind and Hydropower Energy Sources

• The Electric or mechanical energy is obtained from surface air currents caused by solar warming of air. Wind energy is the world’s fastest growing source of energy since wind results from sun warming the atmosphere (clean source of energy with little to no waste ) can be profitable in rural areas with constant wind and or few environmental problems (kills birds and bats).
• Hydropower relies on flowing or falling water to generate mechanical energy or electricity where sun’s energy drive hydrologic cycle which Generates 19% of world’s energy traditional hydropower is only suited for large dams.
• New technology may be able to utilize low flow waterways where the problems with Dams are that it Changes natural flow of rivers , Disrupts migratory fish patterns and Leads to Potential dam breaks Ocean waves from winds can potentially turn a turbine and create electricity

Other Renewable and Conservation Energies

• Geothermal energy is extracted from the Earth’s interior for either space heating or generation of electricity which created by volcanoes or Reservoir used directly for heat or to generate electricity with the geothermal heat pumps that use difference in temperature between surface and subsurface. Tidal Energy is a Form of renewable energy that relies of the ebb and flow of the tides to generate electricity

Hydrogen as a Fuel Source

• Advantages to Hydrogen as a fuel source: Very high energy density, Can be produced from any electrical source (Electrolysis), No greenhouse gases and few other pollutants and Can be use in vehicles
• Disadvantages to Hydrogen as a fuel source: Highly volatile (requires special storage) and Relatively inefficient across the whole life cycle (creating it to using it to create power to actual power use)
• Fuel cell: Device that directly converts chemical energy into electricity where Requires hydrogen from a tank and oxygen from the air Similar to a battery, only the reactants are supplied from outside source with an average 40-60% efficiency

Energy Consumption with Efficient Technologies

• High performance insulation, advanced window glazing, and tighter sealing designs limit heat loss. Can be used with Energy efficient appliances, Automobiles, Aircraft technology; compact fluorescent light bulbs.
• Cogeneration is the production of two useful forms of energy from the same fuel.