How to replace all those big GHG spewing power plants with solar panels on buildings, wind farms, and distributed biogas power generation plants?  And control the flow so that the grid still operates consistently as with the old central power plant design.

You do that with this.  A smart grid, this Xcel energy project is very encouraging.

Transformation of existing metering infrastructure to a robust, dynamic communications network, providing real time, high-speed, two-way communication throughout the distribution grid.
· Conversion of substations to “smart” substations capable of remote monitoring, near real-time data and optimized performance.
· Installation of thousands of in-home control devices and the necessary systems to fully automate home energy use.
· Integration of infrastructure to support up to 1,000 easily dispatched distributed generation technologies (including plug-in hybrid electric vehicles with vehicle-to-grid technology; battery systems; wind turbines; and solar panels).

Along with conservation from plugin hybrids and ground source heat pump heating/cooling, this renewable distributed grid would provide a stable source of all the energy we need. 

A smart grid can store energy too, as backup emergency battery power in buildings, in your own home, giving storm outage backup, and in heat or cold for heating or summer cooling in building mass   High load heating/cooling can be done for a 24 hour cycle, when excess wind or solar power is available.

Habits and values would change with the technology.  Once conservation takes on actual social status.  It's coming, the most admired, talked about  people will go green.  Distributed social values to match the distributed grid.