 TWO SCOTS entrepreneurs have signed a contract with the largest utility company in the Balkans to advise the region on reducing carbon dioxide emissions.  Colin armstrong-Bell and Duncan Spinner, both former officers in the argyll and Sutherland Highlanders, have secured the project, potentially worth as much as GBP40 million, following a public tender in Bosnia Herzegovina.  Through armstrong-Bell's consultancy firm Trade Greener, the pair will work with the Bosnian state-owned energy firm, JP Elektroprivreda, on the carbon reduction project, which is understood to be the largest of its kind in the Balkan region.  The project will include advising the utility on how to modernize its power plants in various parts of Bosnia, making them both more efficient and environmentally-friendly.  along with its local consortium partner, Trade Greener is also bidding for a second round of work, valued at a further GBP40m, to assist with the construction of four hydro plants and a wind farm.  armstrong-Bell, originally from ayrshire, said the contract win comes after three years of negotiations.  "Having taken three-and-a- half years to bring the project to signature, we have taken a long-term view on the Balkan region as a whole.  "I believe this landmark project will pave the way to many other high-quality environmental projects within the region that we have diligently been working on. We are presently working on developing renewable energy projects in the region. Bosnia sources 40 per cent of its energy from hydro plants."