Environmental advocates often talk as though moving quickly toward renewable energy were simply a matter of building more wind turbines and solar farms.
And to some extent, it is: As the price of solar and wind drops, the barriers toward steeply reducing (even eliminating) our dependence on fossil fuels are largely political. The growth of wind power, for instance, has been hindered by fitful Congressional support for tax credits for wind power; by contrast, states with strong incentives for rooftop solar have seen homeowners increasingly adopt it.
Meanwhile, many states require of their utility companies ever-rising use of renewables, but in some of these states supporters of such laws must fight conservative legislators’ efforts to freeze or lower the percentage of renewables in their energy portfolios. And states including Pennsylvania face ongoing controversy over “net metering,” the mechanism that allows homeowners and businesses with their own solar arrays, say, to sell electricity back to the grid. (Utilities claim that too much net metering would cripple them financially.)
However, technical barriers to broader use of renewables do exist. That’s why researchers including University of Pittsburgh professor Tom McDermott recently began a three-year, $4 million U.S. Department of Energy study on integrating solar into the grid.
The biggest issue arises from the fact that solar energy is variable: It fluctuates with the amount of sunshine at a given moment. The greater the percentage of solar input in a particular grid, says McDermott, the higher the risk a sudden influx of power will overwhelm the system, causing outages and damaging equipment.
This isn’t yet a widespread problem; in Pennsylvania, for instance, there simply aren’t enough solar panels in operation. But McDermott says that states like New Jersey, Massachusetts and others out west are approaching that point. And while it still accounts for only about a half-percent of overall U.S. energy consumption, solar has been growing rapidly. Between 2011 and 2015, according to the DOE, utility-scale photovoltaic generation grew 23-fold. With prices plummeting — utility-scale costs dropped 64 percent between 2008 and 2014, according to trade group The Solar Energy Industries Association — that trend should only continue. The SEIA, for instance, expects solar capacity to double in the next two years.
When new generators apply to connect to the grid, utilities must project the impact of the new power source. Some variation in power is acceptable, but if a utility’s modeling is off by just 1 percent, trouble can ensue. McDermott and Pitt — along with the Sandia National Laboratories, the National Renewable Energy Laboratory, Georgia Tech, the Electric Power Research Institute and power-software engineering company CYME — want to create faster and more accurate open-source modeling software for utilities to use.
McDermott knows the terrain: Before coming to Pitt, in 2012, he worked for decades at Westinghouse and as a consultant for electric utilities. Utilities are often labeled resistant to change; critics blame the utility lobby for weak renewable-energy targets in some states, for instance. But, says McDermott, “They’re concerned about the environment, too.” However, it’s the utilities that are the targets of customer complaints when the power goes out, and they worry about the extra time and equipment needed to adapt to new sources of energy. “That’s where the resistance comes in: Who’s going to pay for it?” he says.
But fans of renewable energy, take note: McDermott says there’s no technological limit on how much of it the grid can accommodate, especially if we’re willing to operate big energy-suckers (like electric clothes-dryers) at off-peak hours to balance demand (likely with help from “smart controls” in the home). Likewise, in an increasingly solar-powered world, improvements in battery technology should help us confront the daily supply-demand gap that occurs after the sun sets but while people are still burning lots of power.
If this still all sounds like a big deal, from McDermott’s perspective the utility sector has already gone through a bigger one: electricity deregulation, which let consumers choose who generates their electricity. That shook things up much more than adapting to solar generation will, he says: “I think this is a smaller change.”
