Electricity: an addition to fueled power plants

Why do we go to so much effort to find, process, and combust or react fuels to generate heat for electricity when all that heat is already provided? This nice essay reflects on the follies of power generation from fossil fuels and nuclear when there's an abundance of free heat (read: geothermal) underground to meet all our water boiling (for steam turbine) needs. Here's a taste:

An even more popular way to boil water with fuel is to blast the tops off of mountains and then dig out the carbon that was sequestered by nature eons ago. We then crush and wash this carbon and store the poisonous residue in ponds. We hope to find a way to safely dispose of this waste someday too, but the rest of the poison, the sulfur, mercury, and heavy and radioactive metals fly out of the smokestack when we burn the coal to boil water. Every ton of carbon we burn unites with oxygen atoms from the air to go up the stack as 3.7 tons of CO2. Since this CO2 has been causing nasty climate problems, we are working on a way to hide it in underground caverns. Unfortunately hiding this much CO2 costs a lot of money so we're spending $407 million next year hoping for a breakthrough idea.