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Scientists Unveil Radical Plan to Drill Into a Volcano For Near-Unlimited Energy
(www.sciencealert.com)
This is a most excellent place for technology news and articles.
With standard near-surface geothermal energy, boreholes up to 200 meters are drilled. The heat difference from that depth is only around 10-15°C, but that's enough to collect the energy to heat buildings.
So yes, drilling into lava areas will spice up things.
Iceland has geothermal power plants going down 2.5km and with temperatures of ~250°C that produce electricity, not heat.