The amount of U.S. electricity generated from solar power is slated to more than double for the seventh consecutive year.

The U.S. Energy Information Administration said that solar has provided 7.4 million megawatt-hours of electricity through June, enough to power about 685,000 homes per year. Aided by a mishmash of federal and state incentives, coupled with plummeting solar panel prices, installations are increasing all over the country — generation this year is more than double the 3.5 million megawatt-hours over the same period last year.

While solar's slice of the U.S. electricity pie is still small — it accounted for just 0.2 percent of total generation in 2013 — the electric utility industry is viewing it as a disruptive force. That's because once residents turn to solar, utility revenues take a hit because they lose a customer.

Some utilities and conservative groups have taken to fighting one of the most pervasive incentives, which is known as net metering. The mechanism allows solar customers to sell excess power back into the grid while remaining connected to it for backup purposes.

Opponents say net metering passes the cost of maintaining the electric grid for solar customers onto non-solar customers.

But its backers say utilities receive benefits because solar suppresses electricity demand during periods of high use, helping utilities avoid running costly "peaker" plants used to head off supply shortages.