# Solar fuels and photosynthesis: Resources and labour

Vast farmland, rare catalysts and sunlight focused 2,500 times

Source page: https://www.materialinsights.org/energy/e_solar_fuels/resources/

What this tab covers The natural resources (land, water, materials, fuel or feedstock) and the labour needed to capture this energy, per unit, with the reason each is needed.

Photosynthesis needs land, water and nutrients on a vast scale. Artificial routes need far less land per unit of fuel but rely on concentrated sunlight, specialised semiconductors, precious-metal catalysts, and water and CO2 as feedstock. Labour figures for these research-stage routes do not exist.

#### Natural resources

| Resource | How much | Why it is needed |
|---|---|---|
| **Land (photosynthesis)** | 48 million km2 for agriculture, 80% of it for livestock and 16% for food crops^[6](https://ourworldindata.org/global-land-for-agriculture) | Sunlight is spread thinly and crops convert under 2% of it, so large areas are needed. |
| **Land (artificial routes)** | No per-unit figure in the sources used^[5](https://doi.org/10.1016/j.joule.2022.06.012) | Mirror fields or panels must collect enough sunlight; desert land unsuitable for crops can be used. |
| **Water and CO2 feedstock** | Inputs for every route; jet fuel combustion emitted about 1,027 Mt of CO2 in 2019^[5](https://doi.org/10.1016/j.joule.2022.06.012)^[8](https://www.thechemicalengineer.com/news/researchers-produce-jet-fuel-from-sunlight-co2-and-water/) | Hydrogen comes from splitting water; carbon for hydrocarbon fuels must come from CO2 captured from air or industry. |
| **Catalysts and semiconductors** | No per-unit quantities; the record photoelectrochemical device uses rhodium^[3](https://doi.org/10.1021/acsenergylett.8b00920) | Catalysts lower the energy needed to form hydrogen and oxygen; semiconductors absorb light and separate charge. Scarce metals are a barrier to scale. |
| **Concentrated sunlight** | About 2,500 suns (thermochemical); concentrated light also used for the photocatalytic record^[4](https://doi.org/10.1038/s41586-022-05399-1)^[5](https://doi.org/10.1016/j.joule.2022.06.012) | Concentration raises temperatures and reaction rates so that small, expensive reactors produce more. |

#### Labour

| Phase | How much | Skills | Why it is needed |
|---|---|---|---|
| **Research and pilot plants** | No figure in the sources used^[5](https://doi.org/10.1016/j.joule.2022.06.012) | Materials scientists, electrochemists, chemical and optical engineers | All artificial routes are still in laboratories and test facilities. |
| **Agriculture and forestry (photosynthesis)** | No figure in the sources used (see the Biomass tile)^[6](https://ourworldindata.org/global-land-for-agriculture) | Farmers, foresters, agronomists | Planting, tending and harvesting turn photosynthesis into usable energy. |

#### Sources

1. [Monolithic Photoelectrochemical Device for Direct Water Splitting with 19% Efficiency (Cheng et al., ACS Energy Letters 3, 1795-1800)](https://doi.org/10.1021/acsenergylett.8b00920) American Chemical Society, 2018
2. [Solar-to-hydrogen efficiency of more than 9% in photocatalytic water splitting (Zhou et al., Nature 613, 66-70)](https://doi.org/10.1038/s41586-022-05399-1) Nature, 2023
3. [A solar tower fuel plant for the thermochemical production of kerosene from H2O and CO2 (Zoller et al., Joule 6(7), 1606-1616)](https://doi.org/10.1016/j.joule.2022.06.012) Cell Press, 2022
4. [Half of the world's habitable land is used for agriculture](https://ourworldindata.org/global-land-for-agriculture) Our World in Data, 2024
5. [Researchers produce jet fuel from sunlight, CO2 and water (citing IEA for 2019 jet fuel emissions)](https://www.thechemicalengineer.com/news/researchers-produce-jet-fuel-from-sunlight-co2-and-water/) The Chemical Engineer (IChemE), 2022

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_solar_fuels/index.md)
- [Overview](https://www.materialinsights.org/energy/e_solar_fuels/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_solar_fuels/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_solar_fuels/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/e_solar_fuels/techniques/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_solar_fuels/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_solar_fuels/links/index.md)