That isn’t necessarily true regarding the need for open land. There are horizontal boring techniques that allow for the pipes to go in under houses or even under streets. The best thing that you can say is where there is a will, there is a way.

The pipes are quite shallow, so can’t see how this would have much of a major effect on heating or earthquake possibilities.

I think the point that you are missing is the system is not manufacturing heat, it is moving the heat that already exists from one location to another. It has been a very long time since I took calculus but I suspect that if you calculate the amount of BTUs being absorbed by the Earth from the Sun, the amount going into the ground by geothermal systems even if everybody used them is such a minute amount that it would not be noticeable.

Remember your thermodynamics. Heat goes to cold, so any heat energy you put in the ground dissipates to colder ground and not to the air.

With geothermal, all that heat would go into the earth’s crust. You say it “dissipates” quickly, but it has to go somewhere– either up (into the atmosphere, raising the local temperatures) or down (deeper into the earth’s crust).

I’m not saying that’s more heat than the earth gets from the sun, but it is certainly ADDITIONAL heat that the earth wouldn’t have gotten otherwise– and concentrated in a small area that is literally riddled with earthquake faults. That doesn’t worry you?

Considering that most geothermal systems use no more than the top 150′ - 200′ of the Earth’s surface (we are talking about only a very small area like 20′ X 20′ surface area for one house - horizontal loops only go down 6′ and cover an area about 2′ X 400′). The heat that you put in the ground is quickly absorbed by the ground and dissapated, not to mention that we are talking about 90 degrees. The energy from the Sun penetrates much deeper than that, you couldn’t possibly deposit more heat than the Sun does.