Understanding Energy, Power, and Sustainability
What is energy?
Nobody knows. – Richard Feynman
It enables us to work. Natural processes cannot create or destroy energy. It can change forms.
Forms of energy – chemical, nuclear, mechanical, radiant, electrical, thermal
What is power? – The rate of energy output or consumption.
Unit of energy – Joules, unit of power – joules per second = watt, unit of energy – watt-hours
1 kiloWatt (kW) = 1000 Watt, 1 MegaWatt (MW) = 1000 kW, 1 GigaWatt (GW) = 1000 MW, 1 TeraWatt (TW) = 1000 GW
What is sustainability? – The quality of causing little or no damage to the environment and therefore able to continue for a long time.
Environmental sustainability – the ability to maintain an ecological balance in our planet’s natural environment and conserve natural resources to support the well-being of current and future generations.
Economic sustainability – practices that support long-term economic growth without negatively impacting social, environmental, and cultural aspects of the community.
Social sustainability – specifying and managing both positive and negative impacts of systems, processes, organizations, and activities on people and social life.
Limits of sustainability – dumping waste, high costs, instability
Demand vs consumption – Demand is the rate at which a piece of electrical equipment uses electrical energy. Consumption is the amount of energy it uses over a period of time.
Consumption reducing emissions – decrease the environmental impact associated with human consumption
Demand elasticity – refers to the responsiveness or sensitivity of the quantity demanded of a good or service to a change in its price, income, or other relevant factors. It measures how much the quantity demanded changes in response to a percentage change in price or income.
The efficiency paradox – occurs when the focus is solely on output, without consideration for quality, sustainability, or the overall impact on efficiency.
Electric vs diesel cars – electric is more energy efficient
Hydropower – a renewable source of energy that generates power by using a dam or diversion structure to alter the natural flow of a river or other body of water. Most widespread clean source of electricity.
Advantages – relatively clean, stable output over a short term, flexible output
Disadvantages – geographical constraint, seasonal variability, local environmental impact, water resource competing with other uses
Three Gorges Dam – Largest hydropower plant in the world. 22,500 MW installed capacity. Equivalent of 22 Armenia’s peak power consumption.
Wind power – a form of renewable energy that harnesses the power of the wind to generate electricity – Wind flow rotating the blades, which in turn rotates the generator. More potential at sea, output depends on wind availability and speed, which in turn depends on wind turbines.
Advantages – relatively clean, very low marginal costs of generation, can be installed at sea->no land competition
Disadvantages – needs highly windy area, connection to the grind from hard-to-reach or mountainous or offshore areas, high variability->difficult to predict, expensive to store->need batteries
Solar power – energy from the sun that is converted into thermal or electrical energy – Photons falling on the panels, exciting electrons and generating electric flow. Unlike other sources, there is no rotating generator involved.
Advantages – relatively clean, very low marginal costs of generation, can be installed at rooftops to a limited extend, relatively quick to construct
Disadvantages – needs a sunny area, high variability->difficult to predict->available only during the day, expensive to store->need batteries
Nuclear power – the use of nuclear reactions to produce electricity – Nuclear fission generating heat, which creates vapor to rotate a turbine.
Advantages – relatively clean, high reliability, stable output, very energy dense->requires little space or infrastructure per unit of energy
Disadvantages – risk of nuclear disaster or public perception, very high capital costs, limited flexibility, nuclear waste
Small modular reactors – advanced nuclear reactors – Nuclear fission generating heat, which creates vapor to rotate a turbine.
Advantages – relatively clean, high reliability, stable output, very energy dense->requires little space or infrastructure per unit of energy, safer than normal reactors, assembled on site from premade parts, smaller than normal reactors
Disadvantages – risk of nuclear disaster and public perception, high cost per WM than for normal reactors, technology not fully commercial yet, nuclear waste
Fusion vs Fission – Unstable uranium splitting into smaller elements vs Hydrogen molecules combined into helium
Fossil fuels – Burning coal, oil, or natural gas to produce heat, which can directly rotate a turbine, or turn water into steam to rotate a turbine. Combined cycle power plants do both.
Advantages – Little issues with availability and variability. Controllable and flexible output. Fuel can be transported over large distances.
Disadvantages – Relatively polluting, High variable costs, GHG effects, Geopolitics
Biomass – Burning biomass to produce heat, turn water into vapor and rotate a turbine OR anaerobic digestion, where microorganisms break down organic waste and release gas in the process
Advantages – Little issues with availability and variability. Controllable and flexible output. Fuel can be transported over large distances.
Disadvantages – Less polluting, High variable costs, GHG effects depend on source
Green hydrogen is defined as hydrogen produced by splitting water into hydrogen and oxygen using renewable electricity.
Blue hydrogen is produced mainly from natural gas, using a process called steam reforming, which brings together natural gas and heated water in the form of steam.
Hydrogen is easier to transport, you can get it without CO2 emissions
Fossils fuels are dense -> more energy stored in them.
Natural gas storage – in liquified or gaseous state, storage tanks and cisterns
Transformation of the electricity grid – high levels of distributed generation, electricity flows in different directions, consumers can also be producers, more data-driven
Flywheels – store electricity mechanically through kinetic energy, reaction time: subseconds, discharge time: seconds to a few minutes, largest in the World: 20 MW (USA)
Chemical batteries (Lithium-ion most often) – store electricity chemically, reaction time: subseconds to seconds, discharge time: minutes to hours, largest in the World: 100 MW (Australia)
Pumped storage – store electricity mechanically through potential energy, reaction time: seconds to minutes, discharge time: several hours, largest in the World: 3600 MW (China)