GUILDERLAND — Simon and Edna Litten aren’t living off the grid yet, but they’re getting closer.

The couple lives in a house on Main Street in Altamont and had solar panels installed on the south-facing roof of their barn four years ago. According to Mrs. Litten, they expect the system to have paid for itself by 2020.

“Saving energy is something we have always been concerned about, even before the recent concern over carbon emissions and climate change,” said Mrs. Litten. “We have always been aware that fossil fuels are finite, and the best way to make them last longer is to use less.”

In solar photovoltaic panels, like the Littens’, individual solar cells made from semiconductor materials connect together to form solar electric molecules and produce electricity. The solar modules combine and connect to form solar electric arrays.

The Littens have been living in their Victorian house since 1980, and said they had been debating alternative energy sources for a few years when they decided to attend a presentation, by a company called groSolar, at the Altamont Free Library.

“We didn’t really do much shopping around for vendors,” Mr. Litten said. “We just went with the company that did the presentation.”

They were lucky, he said, that they had recently removed some trees from their backyard and replaced their barn’s roof, because it provided the perfect platform for installing a solar panel system.

The vendor, he said, had to perform a site evaluation before it would agree to install the system, in order to make sure there was an appropriate place for it.

“You can’t just call up a company and say you want solar panels and they’ll come over and do it,” said Mr. Litten.

The company also evaluated the Littens’ prior electricity consumption in order to choose the number of panels they would need.

“We used less energy than the average household even before we had the solar panels installed,” said Mrs. Litten. The Littens don’t have an electric heating system and don’t use an electric dryer, and generally try to be conservative energy users.

The cost of the system was roughly $20,000, said Mr. Litten, but they received an incentive from the New York State Energy Research and Development Authority, as well as state and federal tax credits, making their total out-of-pocket cost less than $10,000.

The incentives program has changed over the past four years, and NYSERDA runs an initiative called NY-Sun, launched by the state in 2012. NYSERDA began transitioning to this system in 2014.

The program provides incentives in a blocked, step-down structure to inspire participation by offering the largest breaks to the first users. The state is divided into regions, based on energy providers, and the regions are broken up into sectors, based on residential and non-residential use. Each region and sector is assigned a megawatt target and a certain incentive level, and that target is called a block.

As applications in each block are submitted, incentives are assigned, the kilowatt hours are added together, and the units are converted to megawatts. When the megawatt target for each block has been reached, the block is closed, and a new block, with a new target and a lower incentive, is opened.

Once all of the blocks for a particular region and sector are filled, an incentive for that block will no longer be offered.

For example, a new block was opened in upstate New York in January, and the incentive offered is $1 per megawatt. The block is 96-percent full. When it is closed, the next block to open will offer an incentive of 90 cents per megawatt.

Solar panels, like the ones installed by the Littens, and those supported by NYSERDA, are tied to an energy provider.

Mr. Litten explained that their panels generate energy when the sun is shining, and, if the Littens use less energy than the panels have generated on any given day, the excess gets “banked” with National Grid. On a day where the Littens use more than the panels generate, they can draw energy from their bank.

That is why, said Mrs. Litten, they are still considered “on the grid.” They have a net meter that measures their production and usage and National Grid manages their banked energy.

They pay a delivery fee of roughly $17 each month to be connected to the grid, but Mrs. Litten said the fee is worth it for the convenience.

If the Littens need to use more energy than their solar panels have banked, they can use electricity from the grid, although Mr. Litten said that has been relatively rare.

For example, he said, last winter there was a month with a lot of cloudy days, and they had to draw from their banked energy, as well as use some regular electricity, but their electric bill was still only 76 cents.

On average, said Mr. Litten, their household uses seven-and-a-half kilowatt hours of energy per day. On very clear late spring, summer, and early fall days, they can generate as many as 13 kilowatt hours of energy. On cloudy days in the late fall and winter, they might generate only two or three hours.

“I count a good day as any day that we produce more than we use,” said Mrs. Litten.

The Littens have researched alternative energy sources because they find the topic interesting.

“It’s a really active subject and it’s important to social policy,” said Mr. Litten. “In your lifetime, you are going to see huge changes.”

The couple quoted some of the slogans they have heard promoting alternative energy including “conservation is cheaper than construction” and the term “negawatts,” which Mrs. Litten explained was a play on megawatts, meant to imply you should try not to use any.

They hope to further decrease their carbon footprint in the future by installing more solar panels and using that energy to power an electric car.

“This is something we really care about; we have grandchildren now and we want them to have a clean environment to live in,” said Mrs. Litten. “It’s exciting to think we might be part of ushering in an era of no fossil fuels.”