Draft:Solar panels
Scarce minerals
The most commonly used types of solar panels contain a variety of metals too scarce to scale up (if the goal is to replace all fossil fuels). See page on solar panel minerals for more details. See solar mineral challenge for requirements & research on less mineral-intensive solar panels.
Recycling
Status quo: Most solar panels are not recycled. Existing recycling plants can't recover very much of the rare metals in the panels. [ELABORATION needed]
As mentioned in the section above, we'll need to use some alternative solar panel tech anyway (one that is less dependent on scarce minerals). Whichever tech we choose, there will still be some metals involved, so it's more important than ever to make sure it can be recycled in a way that recovers those metals.
Intermittency
This section has not been filled in yet.
Land usage
Does not include most farm land.
https://ourworldindata.org/land-use
https://www.newport.com/t/introduction-to-solar-radiation
http://www.ftexploring.com/solar-energy/insolation.htm
Does not include the fuel used in generating electricity. See [energy.tes] for that.
Citation: "Key World Energy Statistics 2020" IEA
- Page 47 - Simplified energy balance table - World energy balance, 2018
In the simplest average case, solar rooftops are all that would be needed.
(calculation loading) If all rooftops in the world were covered with solar panels, the energy produced is just about equal to today's global energy demand.
But of course life is more complicated:
- Geography: Some regions may need more energy than the local rooftops can provide, while other regions may be the opposite. Power lines can only reach so far.
- Countries with extreme temperatures need more energy for heating and cooling.
- Local industry is a major part of energy demand, but it doesn't correlate neatly with local rooftop area.
- Very high-density cities may not have enough rooftop space per capita. Sides of buildings have limited sun when they're obscured by other buildings.
- Inequality: Most of the world today is in poverty. If every nation was developed, the demand for energy would be a lot higher than the status quo used in the calculation above.
- Lower efficiency: Since conventional solar panels are too mineral-intensive to scale up, we need some alternative which will probably be less efficient at converting sunlight into electricity.
There is at least one factor that makes this easier:
- Electric vehicles are more energy-efficient than gasoline or diesel vehicles.
In general, rooftop solar can almost always provide enough electricity for a home (and even charge an EV in many cases), but not always enough for heating. Burning hydrogen gas (generated from wind power) could probably make up the difference in most cases.
Compared to wind power, solar is far less land-intensive