Electricity Market and "The Conversation"

Several articles by Mike Sandiford,  Director, Melbourne Energy Institute at University of Melbourne  and The Conversation contributor have caught my eye recently. Researchers have access to a wide variety of statistics and information sources us regular people don't have. As a Librarian I know its out there, all this information, but don't have the time and expertise to follow. So I find these graphs really interesting.
Mike's recent post "Who's afraid of Solar PV' on The conversation, 21 August 2012 filled in more about the effect solar PV is having on the electricity market and I enjoyed the "Death Spiral" analogy. Here is one of his graphs- showing the effect solar PV is having on demand of electricity in South Australia by time of day

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Average demand for mains electricity in South Australia as a function of hour of day. Red line is the average for the two financial years from July 2007 to June 2009. Blue line is for financial year 2011-12. Left panel shows absolute demand, right pane shows demand changes referenced to 2007-09 averages as a percentage. Data from AEMO, figure by Mike Sandiford

It shows that the enormous uptake of solar PV is having an effect on the delivery of power, particularly in the middle of the day as would be expected.  That is has reduced the " peak hourly revenues by almost 90% between 2007-09 and 2011-12, contributing to a 30% decline in the annual wholesale revenue."

So who's afraid of solar PV! The whole current setup of electricity generation particularly by coal fired power stations. Thus paving the way for new investment and cleaner investment - power from the people in more ways than one. 
However, what do we do for those who cannot afford solar PV or those who don't have roof-space? Geo-thermal?, Wind energy or ??