 SCOTLaND is on course to generate all its electricity from renewable sources by 2020, according to First Minister alex Salmond.  He made the comment as he met the head of the world s largest wind power company, ScottishPower Renewables (SPR), to officially open two windfarms in South ayrshire.  Mr Salmond joined Ignacio Galan to open the  28-turbine Mark Hill and 60-turbine arecleoch windfarms, near Barrhill, which together can power 100,000 homes. Glasgow-based SPR now operates 24 windfarms, 15 of which are in Scotland.  SPR has spent ?1 billion on developing wind energy in the past decade and said more than 2000 people have worked on building and managing its windfarms.  Mr Salmond said:  It is through the leadership of companies such as SPR that we have made such progress and why, as we increasingly develop our offshore energy resources, I am confident that we will achieve our target for Scotland to generate from renewables the equivalent of 100% of our own electricity needs by 2020.  However, a report last week by Inverness-based Mackay Consultants said the goal to generate 100% of energy needs from green sources by 2020 was unrealistic, unachievable and not in the best interests of energy consumers.