Aggreko, the temporary power and temperature control firm, has said that expectations for the full year remain unchanged after an in-line first quarter, though its performance remains mixed across its two main divisions.Underlying revenues grew by 8.0% in the three months to March 31st which represents a slowdown from the 14% growth seen in 2012. Underlying revenues exclude sales from the London Olympics, last year's acquisition of South American power rental firm Poit Energia, pass-through fuel and currency movements.On a reported basis, group revenues rose by a lesser 7.0%, down from 13% for the whole of last year.Aggreko highlighted a "very strong start to the year" in the Local business, its largest division which rents power and temperature control systems, with 17% more power on rent than a year ago. The firm said last month in its full-year results that it had seen "almost 20%" more power on rent at the start of the year.Local revenues were up 10% on an underlying basis and 16% higher on a reported basis.However, trading in the smaller Power Projects division, which builds and operates temporary power plants, still remains subdued with underlying revenues up 5.0% but reported sales down 3.0% due to lower levels of pass-through fuel."The pattern of trading is largely unchanged from that described at our results presentation on March 7th; the Local business has made a strong start to the year and trading in Power Projects remains subdued, although the prospect pipeline has improved," Aggreko said.