The Glasgow-based company, which installs and maintains meters, said its recent takeover of Welsh firm Utility Partnership had helped boost revenues by 44 per cent to £18.9m in the first six months of the year.
Chief executive Alan Foy said the acquisition meant SMS can now "offer our expanded customer base a full gas and electricity proposition".
The deal brought with it thousands of clients including Centrica, Sainsbury's and Vodafone.
The enlarged company now has a portfolio of 534,000 meters, with more in the pipeline following a three-year deal signed in July to upgrade half of British Gas's business customers.
The tie-up with Utility Partnership, which has more than doubled the number of SMS employees to more than 290, has also lined up chances to expand internationally, the firm said yesterday.
Fast-growing SMS had already brought in 40 more staff before the acquisition, opening another office on Glasgow's St Vincent Street earlier this year to accommodate them all.
The company spent £15m buying more metering equipment in the first six months of 2014, up from £10.5m in the same time last year.
SMS, founded in 1995 and floated on the Alternative Investment Market in 2011, makes about half of its revenues from installing meters and half from managing existing meters.
Pre-tax profits rose 40 per cent to £4.6m. As a result, the company announced an interim dividend of 0.94p per share, up 34 per cent on last year, to be paid out on November 21.
"SMS looks forward with confidence to the opportunities in the UK and internationally as we drive our vision to be the leading independent provider of smart metering solutions to suppliers in the utility sector with the highest levels of customer service," said chairman Paul Dollman.
The UK Government wants all households and small businesses to use smart meters by 2020, allowing them to keep track of their energy use in real time.
This ambition goes further than the European Commission's target to have 80 per cent of homes and firms using smart meters by the end of the decade.
Energy companies have turned to firms such as SMS to upgrade their customers to advanced and smart meters.
Shares in the company closed up 3.6 per cent at 393.75p. SMS's stock has risen by a third since the start of the year.