Solar Farm, East-Coast Style

Brookhaven will soon be home to the largest solar farm in the eastern United States. The Long Island Solar Farm, being constructed by BP Solar and the Long Island Power Authority on Brookhaven Lab's campus, will produce 32 megawatts of power when complete - enough to power about 4,500 homes.

Just about six months after site preparation work began in November, the farm is now more than halfway complete. To date, workers have mounted nearly 90,000 of the 164,000 solar panels that will make up the array and have installed 4,600 of the 6,800 racks that hold the panels in place and tilt them toward the sun.

In addition to providing power for Long Island and New York State, the solar farm will help researchers address many of the challenges facing large-scale, grid-connected solar plants. Brookhaven scientists will use data from the farm to study the effect of northeastern weather - not always the sunniest - on power output. In addition, a small plot of the array also will be used by Brookhaven scientists to test new solar technologies.

The large array will incorporate advanced monitoring equipment that will allow researchers to monitor, in real time, how much power is being generated in relation to the amount of cloud cover present. This gives scientists the ability to look at the impact of microscale elements like individual clouds on the array's output.

Researchers also are developing the ability to predict, up to 30 minutes in advance, the output of the large array based on observation, tracking, and evaluation of cloud conditions. This technique, known as "nowcasting," uses optical imaging of the clouds and sophisticated software to identify shapes, track movements, and evaluate the optical density of the clouds -- that is, how much light is filtered by clouds overhead. This type of near-term forecasting will help utilities anticipate changes -- such as dips in solar-generated power at times of cloud cover -- and make adjustments before they occur to maintain constant power on the grid.

Research at the smaller array, while still under discussion, will likely include testing of new inverter and power supply technologies, as well as advanced energy storage devices that will enable power generated during peak output times to be saved for use during times of greatest demand - when the sun may not be shining.

For more photos, check out BNL's Flickr site.