The danger of green energy; Wind and solar power putting new stress on old electrical grid 

In a sprawling complex of laboratories in Golden, Colo., a supercomputer named Peregrine does a quadrillion calculations per second to help scientists figure out how to keep the lights on.

Peregrine was turned on this year by the U.S. Energy Department. It is the size of a Mack truck.

Its job is to figure out how to cope with a risk from something the public generally thinks of as benign – renewable energy.

Energy officials worry a lot these days about the stability of the massive patchwork of wires, substations and algorithms that keeps electricity flowing. They rattle off several scenarios that could lead to a collapse of the power grid – a well-executed cyberattack, a freak storm, sabotage.

But as states race to bring more wind, solar and geothermal power online, those and other forms of alternative energy have become a new source of anxiety.

The problem is that renewable energy sources add unprecedented levels of stress to a grid designed for the previous century.

“The grid was not built for renewables,” said Trieu Mai, senior analyst at the National Renewable Energy Laboratory.

The frailty imperils lofty goals for greenhouse gas reductions. State and federal officials now are spending billions of dollars in ratepayer and taxpayer money in an effort to hasten the technological breakthroughs needed for the grid to keep up with the demands of clean energy.

Making a green-energy future work will be “one of the greatest technological challenges industrialized societies have undertaken,” a group of scholars at the California Institute of Technology said in a recent report.

The role of the grid is to keep the supply of power steady and predictable, with engineers carefully calibrating how much juice to feed into the system as everything from porch lights to factory machines are switched on and off. The balancing requires painstaking precision. A momentary overload can crash the system.

Green energy is the least predictable kind. Nobody can say for certain when the wind will blow or the sun will shine. A field of solar panels might be cranking out huge amounts of energy one minute and a tiny amount the next, with the arrival of a thick cloud. In many cases, renewable resources exist where transmission lines don’t.

California has taken some of the earliest steps to address the problems. The California Public Utilities Commission last month ordered large power companies to invest heavily in efforts to develop storage technologies that could bottle up wind and solar power, allowing the energy to be distributed more evenly over time.

Whether those technologies will ever be economically viable on a large scale remains hotly debated. The commission mandate nonetheless requires companies to produce enough storage by 2024 to power roughly 1 million homes.

“Energy storage has the potential to be a game changer for our electric grid,” Commissioner Mark Ferron said.

Some utility officials warn, however, that the only guarantee is that ratepayers will be spending a lot. The commission’s goals, while laudable, “could cost up to ($3 billion) with uncertain net benefits for customers,” Southern California Edison declared in a filing.

But regulators are desperate to move past the status quo. Already, power grid operators in some states have had to dump energy produced by wind turbines on blustery days because regional power systems had no room for it.

“We are getting to the point where we will have to pay people not to produce power,” said Long Beach, Calif., Mayor Bob Foster.

A bigger fear is that the grid is becoming more vulnerable to collapse, leaving the public exposed to the kind of blackouts that hit San Diego, parts of Arizona and a chunk of Baja California on a blistering hot September day in 2011. Rush hour traffic jammed as streetlights went black. Flights were grounded. Pumping stations came to a halt, causing sewage to flow onto beaches. People got trapped in office elevators and on rides at Sea World.

An employee’s misstep at a substation near Yuma, Ariz., caused that blackout, but energy experts see it as a harbinger of the sorts of problems that could become frequent if the nation fails to refashion its outmoded power grid.

Foster has been working with other regulators and power company executives to redesign the system. The work involves ideas for building vast networks of electrical lines, solar and wind power plants, and backup natural gas plants that can keep the lights on when shifts in weather cause renewable sources to falter. But planners are struggling to plot designs without knowing whether regulators will approve the transmission lines to support them.

“One of the biggest challenges is you can’t create a market for these resources without solving the demands of moving electricity from one physical place to another,” said Neil Fromer of Caltech’s Resnick Sustainability Institute. “But you can’t solve that problem until you understand what the market structure looks like.”