Three Maine-based clean tech companies are vying for top prizes in regional competitions.

Startups Delta Dewatering of South Portland, F.E. Wood Natural Energy of Portland and Surge Hydro of Belfast have been accepted to the Cleantech Open Northeast’s Class of 2016. Also, Surge Hydro has been accepted into the MassChallenge business competition, according to a news release from Environmental and Energy Technology Council of Maine (E2Tech), a trade association that fosters the development of companies in the environmental, energy and clean tech sectors.

The Cleantech Open is the world’s largest cleantech accelerator with a mission to find, fund and foster entrepreneurs with ideas to address urgent energy, environmental and economic challenges.

Since 2005, more than 1,000 startups have participated in its annual accelerator and mentorship program, raising a total of more than $1.2 billion and creating thousands of jobs.

The program provides extensive mentoring, training, business clinics, access to investors and capital, and opportunities to showcase to the media and the public. MassChallenge is a similar global accelerator program for top-notch startup companies in all fields, according to the E2Tech release.

Delta Dewatering provides cost-effective, innovative technology to clean water, while F.E.Wood Natural Energy developed a project to supply high-quality wood pellet fuel to heating markets in the Northeast. Surge Hydro incorporates technologies into hydroelectric facilities and infrastructure to build sustainable grid networks with more efficient power production.

Jeff Marks, E2Tech executive director, said in the release that last month, the 2016 U.S. Clean Tech Leadership Index – a data-based comparison of all 50 states among 70 technology, capital and policy indicators – found that Maine improved its ranking from 22nd to 18th since last year. Also. Maine rose to the top 10 in the technology indicator, coming from 15th in 2015 to ninth place this year.