Global Energy is the biggest private employer in the Scottish Highlands. Its current workforce is about 1,800, and turnover stands at £230m; among other activities, it maintains offshore oil and gas installations, and is involved in wind, tidal and wave power. One administrative centre is in Inverness, but for a flavour of the scale of its operations, you need to drive for 20 minutes to the banks of the Cromarty Firth in Invergordon, where Global employees crowd on to vast drilling rigs. Just over the water at Nigg, the company is aiming to open a plant that will also look into wind turbines, and create some 1,500 jobs.

Alex Salmond – first minister and leader of the Scottish National party – paid a visit to Nigg last week, bigging up his promise to produce 100% of Scotland's electricity from renewables by 2020, and talking about nothing less than "the reindustrialisation of Scotland on a huge scale". It was a characteristic performance; over the last few weeks, as Labour's woeful campaign has resorted to shrill warnings about the perils of independence, and the Scottish Lib Dems have shrivelled in the spotlight, Salmond alone has shone – and looks set to win a second term, by as many as 62 to seats to Labour's 51. His secret? A mixture of charisma, chutzpah and a showman's sense of Scotland's promise, despite the chill winds of austerity.

Global's name came up in the flurry of posts put up in response to our initial request for opinions and testimony about this week's elections, and the path Scotland has taken since devolution. A good deal of the resulting online conversation took the form of a predictable dogfight between two sides: Scots who want out of the union, and quick ("You can pay for your own bloody Olympics, Millennium Dome, Jubilee line"); and rather sour English voices who see Scotland as a dissolute sibling, forever bankrolled from London ("Scotland is living in a La-La land, where money grows on trees and can be spent on endless pet projects, and no one has to grow up", was one, hardly unique, contribution).

If you hold to the caricature of Scotland as an embodiment of post-industrial woe, Salmond's vision of a country reborn as a green dynamo might seem unlikely. Even if you don't, hearing a first minister talk in such ambitious terms when his government's budget falls by £1.3bn in 2011-12 alone could prompt a disbelieving smirk.

The demise of Salmond's old idea of a north European "arc of prosperity" including Iceland and Ireland hardly helps either. But with investment in Scottish renewables by Mitsubishi and the Korean firm Doosan, and national successes in the life sciences, computer games and more, his vision of a resurgent Scotland doesn't come from nowhere – and Inverness is a good place to immerse yourself in it.

The city is 618 miles from Westminster, and feels like it. Granted city status in 2000, this was at one point the fastest growing metropolis in western Europe, and its population of about 60,000 is projected to double in the next 30 years. Even the fact that its Westminster MP is Danny Alexander of the Lib Dems (after boundary changes, the SNP's Fergus Ewing will almost certainly keep his seat in the Scottish parliament) cannot dampen a sense of large-scale wellbeing; certainly, it feels more at ease with itself than most similar-sized places I know south of the border.

All that said, some subjects prompt uneasy shrugs: problems with drugs and drink; why places such as Merkinch and South Kessock are unemployed enclaves while, apparently, most of the jobs in hotels and restaurants are taken by recent arrivals from eastern Europe. At a local branch of the Highland Food Bank, offering help to those waylaid by the benefits system, I'm told that demand has risen by 30% in a year – and worse is to come once Westminster's new benefits regime kicks in. All this attests to a more complicated picture than that laid out in the city's official bumf, and yet it neglects aspects of the local atmosphere – matters of mood and disposition – that may not be reducible to statistics, but seem real enough.

And so, perhaps, it is with the Scottish elections. People here seem to divide 50/50 on the question of independence, but just about everyone I meet is prepared to admit that Salmond has qualities that chime with the local sense of possibility. That points up something often missed: that the carping about Salmond's bumptiousness – or how his promises of prosperity, opportunity and help for all can possibly square with such hard times – misses the key to the SNP's appeal, and Scotland's immediate political future.

Neither are about squabbles over spending plans and fiscal arithmetic. They have precious little to do with whether the end of the union is or isn't a viable prospect. Rather, if the SNP is granted a second term on Thursday, the explanation will come down to the question that decides so many elections: who are the optimists?

"This is a wonderful, beautiful, peaceful, sunny place to live," one local SNP voter tells me, before selling me a Salmond-esque vision of a promising economic future. "We've got plenty of wind, and tidal power," he says. "In time, things will happen." He should know: he's a successful tour guide, keen to get back to work, with a microcosm of the world waiting for his services.