Because unless you sit on top of a volcano, amount of renewable geothermal energy is minuscule. In most places on Earth it's somewhere around 40 mW/m2 (i.e. accounting for conversion losses you need to capture heat from ~500 m2 to renewably power one LED light bulb!). In other words, in most places geothermal plant acts more like a limited battery powered by hot rock, so unless drilling is extremely cheap, it does not make economic sense compared to other energy sources.

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dns_snek 14 hours ago | parent | next [-]

> In most places on Earth it's somewhere around 40 mW/m2 (i.e. accounting for conversion losses you need to capture heat from ~500 m2 to renewably power one LED light bulb!)

Ground-source heat pumps extract about 1000 times more power from ground loops, where does the difference come from?

	▲	kragen 3 hours ago \| parent \| next [-]
		Ground-source heat pumps are irrelevant to geothermal energy sources, and it's unfortunate that the article mentioned them. Ground-source heat pumps are just storing heat from the air during the summer and retrieving it during the winter.
	▲	bluGill 9 hours ago \| parent \| prev [-]
		A number of sources. Often the air above - ground source relies on the ground being the average temperature of the year round air once you get deep. They also tend to run in heating mode half the year, and cooling mode the other half.

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kragen 3 hours ago | parent | prev | next [-]

While it's true that a geothermal plant is a limited battery powered by hot rock, that doesn't mean it doesn't make economic sense compared to other energy sources.

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piva00 14 hours ago | parent | prev [-]

I think OP meant technology for drilling becoming cheaper rather than the near-surface availability of it.