The much-debated study The Limits to Growth, which was published as early as 1972 by Dennis L. Meadows et. al. on behalf of the “Club of Rome”, already predicted shortages of natural resources and especially fossil fuels (coal, oil and gas) alongside irreparable damage to the environment if nothing was done about the world population growth, industrialization, pollution, food industry and exploitation of resources of that time. Oil crises and price increases of the past have shown how nearly every state is dependent on oil. Even the seemingly eco-friendly nuclear power uses limited resources and poses severe and still unsolved problems concerning the permanent disposal of its waste.
With all these insights, the focus is on other eco-friendly and safe approaches to power generation independent of limited resources, yet sufficient in quantity. One concept is the use of renewable energies in connection with storage of excess energy. Before fossil fuels were discovered, mankind relied solely on renewable energy, and fossil fuels really only gained their importance during the course of the industrialization.
Renewable energies include:
- Wind power
- wind turbines
- Hydropower
- hydroelectric dam with turbine
- run-of the-river hydroelectricity
- Pumped-storage hydroelectricity
- Tide power
- Solar energy
- Photovoltaics
- Solar thermal energy
- Biomass
- Thermal conversion
- Chemical conversion
- Biochemical conversion
- Biofuel
- Bioethanol
- Biodiesel
- Biogas
- Geothermal energy
- Geothermal heating
- Geothermal heat pump
One way of storing excess energy is by using electricity to generate hydrogen through electrolysis of water, which can then later be oxidized to generate electric energy from the chemical energy stored in the hydrogen.
Relevant scientific concepts:
| Energy | Definition | The ability of a physical system to do work or transmit light or heat. |
| Formula | E | |
| Units | one joule (1J), one watt-second (1Ws), 1J = 1Ws | |
| Measuring instrument | --- | |
| Force | Definition |
Any influence that causes an object to undergo a certain change. |
| Formula | F = ma (mechanic) or F=qE (electric) | |
| Units | one Newton (1N) | |
| Measuring instrument | spring scale | |
| Work | Definition | A physical system does work, when there is movement under the action of a force. |
| Formula | W = Fs (mechanic) or W = qU (electric) or W = ΔE | |
| Units | one newton-meter (1Nm), one joule (1J), 1Nm = 1J | |
| Measuring instrument | --- | |
| Power | Definition | The rate at which energy is transferred, used or transformed. |
| Formula | P = ΔE/t = W/t (mechanic) or P = UI (electric) | |
| Units | one watt (1W), one joule-second (1Js), 1W = 1Js | |
| Measuring instrument | --- | |
| Electric Current | Definition | A flow of electric charge through a conductive medium. |
| Formula | I = q/t or use Ohms law | |
| Units | one ampere (1A) | |
| Measuring instrument | ammeter | |
| Voltage | Definition | The „force or push“ that moves electric current through a circuit. |
| Formula | U = W/q or use Ohms law | |
| Units | one volt (1V) | |
| Measuring instrument | voltmeter, potentiometer | |
| Electrical Resistance | Definition | The opposition to the passage of an electric current through an electric element. |
| Formula | R = U/I or R = ρℓ/A | |
| Units | one ohm (1Ω) | |
| Measuring instrument | ohmmeter | |
| Temperature | Definition | A measurement of how hot or cold a body is. |
| Formula | T or ϑ | |
| Units | one kelvin (1K) or one degree celsius (1°C) | |
| Measuring instrument | thermometer | |
| Heat | Definition | The amount of energy that is transferred from one system to another by thermal interaction. |
| Formula | Q = ΔE or Q = cmΔT | |
| Units | one joule (1J) | |
| Measuring instrument | --- | |
| Irradiance (Light intensity) | Definition | The power of light per unit area incident on a surface. |
| Formula | I = P/A | |
| Units | one watt per square meter (1W/m²) | |
| Measuring instrument | light sensor |
Relevant scientific concepts and phenomena
- Energy conversion
- Heat transfer
- Electric generator
- Direct and alternating current
- Electric circuit
- Ohms law
- Kirchhoffs laws
- Inner photoelectric effect
- Electrolysis
- Fuel cell
- Fermantation
- Ecosystem
- interaction between animate and inanimate nature
- Water cycle (hydrological cycle)
- …