Earth power or sun power...what's the better investment?

Producing free electricity with renewable energy is great...the answer to all of our energy problems. No more burning dirty coal or oil, no gas, no nuclear...just an infinite supply of free energy by simply putting up a wind generator or some solar PV. According to a recent report by Lawrence Berkeley National Lab, the capital cost to install PV was about$5,300 / kW for residential systems, $4,600 / kW for system up to 100 kW, and for utility scale projects, about $2,500 to $4,000 / kW. The expected lifespan of PV panels is about 25 year. Considering that the sun doesn't shine at night and cloud cover....

.... a 1 kW system will produce about 50,000 kW over 25 year. That's a cost of between $0.05 to $0.10 / kWh. That doesn't consider maintenance of the system, energy storage, or the cost of interest you could have earned on the capital cost during the 25 years...for "free" electricity.

Let's compare the cost of producing "free" electricity to the cost of reducing the need for electricity by installing a GCHP system in a typical home. If we look at a typical home, the cost of installing a GCHP system...say a 3-ton (10.5 kW) heat pump, the additional cost, compared to a conventional heating and air conditioning system, might be $15,000. it draws about 3.0 kW of power and will run about 3,000 hours per year to heat and cool a home. During those 3,000 hours it will transfer about 22,500 kWh of energy to and from the ground. Over a 20 year life it will transfer about 450,000 kWh. For the $15,000 investment you get about 450,000 kWh of energy from the ground...about $0.033/kWh.

A dollar invested in the earth provides power at about 50% to 70% less the the cost of producing power with the sun.