# Geothermal direct use and ground-source heat pumps: Resources and labour

What lies underground: boreholes, plastic pipe and a compressor

Source page: https://www.materialinsights.org/energy/e_geo_direct/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.

Heat pumps need ground for the loop, plastic pipe, a refrigerant circuit and electricity; direct use needs wells, heat exchangers and insulated pipe networks.

#### Natural resources

| Resource | How much | Why it is needed |
|---|---|---|
| **Ground or boreholes** | Vertical holes about 4 inches (10 cm) wide, 100-400 ft (30-120 m) deep and about 20 ft (6 m) apart; horizontal trenches at least 4 ft (1.2 m) deep (metric conversions calculated)^[1](https://www.energy.gov/energysaver/geothermal-heat-pumps) | The loop needs enough contact with soil or rock to draw heat without freezing the ground. |
| **Plastic pipe and antifreeze fluid** | Not quantified per kW^[1](https://www.energy.gov/energysaver/geothermal-heat-pumps) | Carries heat from the ground to the heat pump; the loop lasts 50 years or more. |
| **Electricity** | About 1 kWh per 4.3 kWh of heat (calculated from field COP)^[2](https://www.zfk.de/energie/waerme/studie-waermepumpen-heizen-altbau-effizient-gasheizungen-co2) | Drives the compressor that lifts the temperature. |
| **Copper and refrigerant** | Not quantified^[1](https://www.energy.gov/energysaver/geothermal-heat-pumps) | Heat-exchanger tubing and the refrigeration cycle; direct-exchange systems use copper tubing in the ground. |
| **Hot water wells (direct use)** | Two 4.5-5 km wells give 64 MWt at Geretsried^[4](https://knowledge.energyinst.org/new-energy-world/article?id=140011) | Deeper wells reach hotter water where no shallow resource exists. |

#### Labour

| Phase | How much | Skills | Why it is needed |
|---|---|---|---|
| **Manufacturing** | Not quantified^[6](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) | Heat-pump and compressor manufacture | Same industry as air-source heat pumps. |
| **Construction** | Not quantified^[1](https://www.energy.gov/energysaver/geothermal-heat-pumps) | Borehole drillers, groundworkers, heating engineers | Loop installation is the main extra cost compared with air-source units. |
| **Operation** | Indoor units last up to 24 years^[1](https://www.energy.gov/energysaver/geothermal-heat-pumps) | Heating technicians | Compressors and pumps wear out long before the ground loop. |
| **All phases** | 161,000 direct jobs in geothermal power worldwide in 2024 (heat not counted separately); about 388,000 in heat pumps of all types^[6](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) | Mixed | Global estimates do not separate geothermal heat or ground-source units. |

#### Sources

1. [Geothermal Heat Pumps (Energy Saver)](https://www.energy.gov/energysaver/geothermal-heat-pumps) US Department of Energy, 2024
2. [Studie: Wärmepumpen heizen auch im Altbau effizient (results of Fraunhofer ISE project WP-QS im Bestand)](https://www.zfk.de/energie/waerme/studie-waermepumpen-heizen-altbau-effizient-gasheizungen-co2) ZfK Zeitung für kommunale Wirtschaft, 2025
3. [Innovative geothermal project powers up in Bavaria](https://knowledge.energyinst.org/new-energy-world/article?id=140011) Energy Institute, New Energy World, 2025
4. [Renewable Energy and Jobs: Annual Review 2025, Table 1](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) IRENA and ILO, 2026

## Other sections

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