In 2016, for the second straight year, Rhode Island’s “green-energy” sector enjoyed double-digit growth, but the increase was well below 2015 gains.

This energy sector consists of jobs in energy efficiency, renewable energy, low-carbon transportation, and renewable heating and cooling such as HVAC and biomass energy.

There were 15,305 green-energy jobs in Rhode Island at the end of 2016, according to a new report from the Office of Energy Resources (OER). The biggest job category was installation — jobs that involve equipment assembly, repair and maintenance. The median wage across all jobs in the sector is $25 an hour. Laborers made the least per hour at $18.29. Supervisors made the highest at $32.43 an hour.

In 2016, Rhode Island’s green-energy sector grew by 11 percent, adding 1,300 jobs. However, that growth was well below 2015, which grew 40 percent by adding 2,900 jobs. In 2014, the first year the OER report was issued, the sector grew by 6.6 percent with 613 new jobs. Rhode Island’s overall job growth for 2016 was 1.1 percent.

The sample size is too small to draw meaningful conclusions about the drop in green-energy growth. But it’s worth noting that the huge 2015 job increase was aided by hiring for the Block Island Wind Farm and the expansion of state’s solar incentives.

As it did in 2015, energy-efficiency jobs dominated the sector in 2016, with close to 9,000 jobs, or nearly 60 percent of the sector. Energy-efficiency jobs climbed by 16 percent last year. Green transportation, the smallest category in the sector, grew by 10 percent, to 279 jobs.

Medium-sized green-energy businesses are also hiring more, as the number of companies with six to 24 employers increased by 18 percent. The number of smaller firms that employ one to five workers fell by 16 percent in 2016.

Nevertheless, 80 percent of companies said they had a “very” or “somewhat” difficult time hiring. The main challenges were cost of living, competition and a small pool of college graduates. About 47 percent of businesses said job applicants need better training.

Here is a look at Rhode Island’s green-energy economy by sector:

Energy efficiency: 59 percent
Renewable heating and cooling: 25 percent
Renewable energy: 14 percent
Transportation: 2 percent

OER predicts solid job increases in the sector moving forward, because of state goals such as 1,000 megawatts of renewable energy and 20,000 green-energy jobs by 2020. This growth will be boosted by the expansion of renewable-energy incentives such as the fixed-price Rhode Island Renewable Energy Growth Program and a state rebate for buying electric vehicles, according to OER.

The state agency also expects the success of the Block Island Wind Farm to grow the offshore wind industry and lead to joint wind projects with Massachusetts. Currently, the local wind industry supports 514 workers. The solar sector employs 1,691. Both the wind and solar sectors increased about 10 percent in 2016.

Rhode Island ranks 12 in the 2017 U.S. Clean Tech Leadership Index. It ranks 10th for business-friendly renewable energy installation.