At first glance, Mainline Power should be on the cusp of something big.  For a start, the Cork-based electrical engineering services firm is operating in the right markets. Some 84 per cent of its business is generated from contracts on renewable energy infrastructure, a high-growth area with an equally high barrier to entry. This work is complex and involves Mainline helping to connect renewable energy plants – both solar and wind – to the power grid.  The company’s business, however, is not confined to renewables. It is a market leader in the wider space of grid connections and has achieved Gold…