For all the talk of a natural gas boom, it takes time to build multibillion-dollar power plants to take advantage of the current glut of cheap fuel. Case in point: In March, the US added a whopping—wait for it—44 megawatts (MW) of new electricity generating capacity, according to the Federal Energy Regulatory Commission (FERC).

That’s enough to keep espresso makers humming in about 30,000 American homes. Not exactly China-scale. But here’s what’s really interesting about that number: March marked the first time that 100% of new generating capacity in the US came from photovoltaic, or solar, power plants. (FERC doesn’t count the electricity generated by solar panels installed on residential rooftops.)

The solar projects FERC does count ranged from a 1.3 MW solar installation at a North Carolina science center to a 26 MW power station built by NRG Solar in the desert east of San Diego, California.

March may just have been an off month for power plant construction. Between January and March, the US added a total of 1,880 MW of new electricity generating capacity. Even so, renewable energy projects—wind, solar and biomass—accounted for 82% of new capacity in the first quarter of the year, and solar alone chipped in nearly 30% of the additional power. Natural gas power plants, on the other hand, added just 340MW, or 18%, of new capacity. And coal? Zip. Zero. Nada.

Overall, 2013 is shaping up to be a slow year. In 2012, the US added 3,833 MW of new generating capacity between January and March, including 1,145 MW of new natural gas power plants.

So what to make of these numbers?

First, expect renewables to be a leading source of new electricity capacity in the US, even if overall they still represent a small percentage of total capacity. (Despite the explosive growth of photovoltaic’s installations in recent years, solar still accounts for just half a percent of the US’ electricity production.)

Why? It’s simply much quicker and cheaper to install thousands of solar panels or erect wind turbines than build a complicated and capital-intensive natural gas power plant.

The trend should continue in 2013: Several giant solar power plants are due to come online later this year, and wind developers face a deadline to break ground on new projects by Dec. 31 to qualify for a crucial federal tax credit.