aLEX Salmond s landslide victory means Scotland will get a definitive judgement on the SNP s promise to meet all electricity demand from green sources by 2020.  His pledge was branded  pure fantasy  by Labour, and UK leader Ed Miliband accused the First Minister of dreaming up  fairy stories  with the ambitious goal.  However, many believe the 100% target is achievable if billions of pounds are channelled in the right direction.  The challenge the Nationalists face is in mounting projects, and the renewable energy lobby will clash with pressure groups every step of the way.  Roughly a three-fold increase in wind power is needed to set Scotland on the right track, but it becomes harder to secure permission for each new project.  Biomass plants and waste incinerators will spark  Nimby  battles with local residents, and offshore power is costly, requiring infrastructure improvements to reach homes and businesses.  Demand-reduction tactics such as taxes are unpopular and Scotland faces a skills gap in renewable know-how. While Strathclyde University and other centres rush to plug this, expertise needs time to grow.  However, the winnings if the gamble pays off are enormous: in Mr Salmond s own words, 130,000 jobs in the  low-carbon economy  and a chance for Scotland to engineer the 21st century just as this country engineered the 19th .  Though his self-imposed deadline is well beyond the five-year term of this Parliament, the time it takes to plan new projects means his cards will be on the table when voters go to the polls in 2016.