We present the results of a number of PV-grid matching simulations performed using hourly generation data from the Israel Electric Corporation (IEC) for the year 2006, together with corresponding meteorological data from Sede Boqer in the Negev Desert. The principal results of this investigation are: (1) the effective flexibility factor (ff) of the IEC grid was close to ff = 0.65, but with a different plant operating strategy, if could have been considerably higher; (2) for ff = 0.65, the largest no-dump PV system could have provided only 2.7% of the annual demand, but for higher flexibilities - up to ff =1 - the percentage penetration could be as high as 17.4%; (3) considerable improvement in penetration can result by relaxing the "no-dump" criterion initially imposed on the PV system; (4) using the IEC's existing plant types, additional penetration can be expected by re-scheduling part of the base-load generating capacity to anticipate expected solar input; (5) for a radically decreased grid flexibility -that might result from IEC decisions about future generator purchases -the required employment of massive amounts of storage would render the potential contribution of PV to be insignificant. (c) 2009 Elsevier Ltd. All rights reserved.