Chrysalix EVC, a clean energy firm backed by a mixture of private equity firms and energy companies, such as EDF, has made 11 early stage follow-on investments over the past year, signalling continued growth opportunities in the clean tech sector.

Energy efficiency technology company Transphorm, already backed by investors including Nihon Inter Electronics Company and Google Ventures, files for $15m fund raise.

Chrysalix Energy Venture Capital has reinvested in Canadian wastewater treatment company Axine Water Technologies in a series A deal worth $5.6m, making it the largest water and wastewater series A financing in North America in the past year and one of the largest internationally in the last two years.

Irish digital power controller maker raises $5.5m C1 funding round from existing investors including Intel Capital and Semtech Corporation.

Energy efficiency motivator Opower is reported to have filed for an IPO.

Ziebel, a Norwegian provider of specialist well intervention services for the oil and gas industry, has closed a round of growth capital raising $10m. The funding was secured from lead investor ConocoPhillips Technology Ventures, along with Chevron Technology Ventures, and Energy Technology Ventures. Existing Ziebel investors Energy Ventures, Viking Venture, Jebsen Asset Management, Investinor, and Klaveness Invest also participated in the round.

Samsung Venture Investment Corporation, the venture capital arm of Samsung Group, has made a strategic investment in XG Sciences. Philip Rose, XG Sciences CEO, said the investment will be used to fund additional research and development of the company's advanced materials. The terms of the investment were not disclosed.

Energy grid management software provider AutoGrid Systems has raised $12.75m in series C financing from investors included Germany-based energy utility E.ON, looking to deploy its big data analytics in making energy cleaner.