[Back to Physical Challenges]
Introduction
This is the fundamental practical challenge facing the human race: our civilization depends upon using vast amounts of energy; the way we use energy is changing the climate and destroying the ecosystem which our survival depends upon; and we would already have all the technology we need to solve the problem of global climate change if only we could generate sufficient energy in a sustainable manner.
The challenge breaks down into several discrete parts:
- generation;
- conversion;
- transportation;
- storage; and
- use.
In practice, the issues of generation and conversion are deeply connected - not least because all generation is in reality a conversion of energy from one form to another. Similarly, in practice, transportation and storage are deeply connected. In current thinking, much of the target use of energy requires electricity, but this can ignore some potential efficiency savings in (for example) combined heat and power systems.
Energy Generation and Conversion
We have to reduce our use of fossil fuels.
- New Scientist article (14 April 2021): Limiting fossil fuel use isn’t enough – we must stop extraction too , possibly also available here: https://www.newscientist.com/article/mg25033301-000-limiting-fossil-fuel-use-isnt-enough-we-must-stop-extraction-too/#ixzz71FE7nhjt
The only potential sources of substantial amounts of energy are:
- sunlight;
- wind;
- hydroelectric
- geothermal;
- sea;
- Nuclear Fission ; and
- Nuclear Fusion.
Energy Transportation and Storage
- Batteries: systems which can generate electricity through chemical reaction
- Fuel cells: systems which act like batteries, but store the energy in a stable form, often as hydrogen
- Bio fuel: substances which can be produced sustainably and generate energy through burning; hydrogen can also be burned
- Gravity: suitable for storage, but not transport; water can be pumped uphill for hydroelectric systems; weights can be raised on towers or in mines; buoyant items can be pulled down underwater (this video describes several possible ways)
Heating
We have to move away from burning fossil fuels to heat our homes and workplaces. What are the alternatives?
- Greater use must be made of electrical heaters.
- We can often move from burning fossil fuel to burning hydrogen, assuming that it has been produced in a green way.
- Ground source and air source heat pumps are also options which we can make greater use of. There is a meeting about air source heat pumps on 16 June 2021.
Activity
Domestic activity:
Our computers are taking up an increasing amount of the world's energy use - both in absolute terms, and as a percentage of the whole. As reported in the New Scientist, the electricity demand from data centre expansions, which is largely driven by the generative AI boom, is expected to double by 2026, matching the energy consumption of Japan today (in 2024).
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