A common argument from utilities is that incorporating more distributed solar power into their network costs them money and requires upgrades. That might not be the case found the recently published Full Cost of Electricity, an interdisciplinary study from The Energy Institute at the University of Austin.
The wide-ranging research, which consists of a series of whitepapers found that wind power and natural gas are now the lowest-cost technologies for new electric generation across most of the US when all costs, including public health impacts and environmental effects, are included. Solar power is still more expensive than wind power overall but its costs continue to come down quickly.
While utility-scale solar power is less expensive rooftop solar there are cases where the costs to utilities of adding rooftop solar are exaggerated, according to the report. “When operational changes or equipment upgrades are required to increase a circuit’s solar hosting capacity, the cost can be relatively small,” the larger study’s whitepaper “Integrating Photovoltaic Generation,” found. This will be an important argument as the US has more potential for rooftop solar power than ever before.
“By offering local generation, residential or rooftop PV reduces the need for transmission facilities to move power from large generating stations to distribution substations,” wrote white-paper authors Suma Jothibasu, a University of Austin graduate student, and Surya Santoso director of University of Austin Laboratory for Advanced Studies in Electric Power and Integration of Renewable Energy Systems. “But the effect on the distribution grid is less straightforward.”
“The conventional distribution grid is designed for neither two-way power flow nor large generation capacity. So the prevailing thought is that the grid will need a costly upgrade to accommodate the high PV penetration,” they wrote in a blog at IEEE Spectrum. “The bottom line? We found that even without hardware upgrades to the distribution circuits, such circuits can handle significant solar generation.”
“Depending on a distribution circuit’s characteristics, the maximum PV capacities it can handle range from as low as 15.5 percent of the median value of the daytime peak load demand (2.6 megawatts in one particular circuit) to more than 100 percent (3.87 MW in another circuit),” Jothibasu and Santoso stated. “These results suggest that significant rooftop PV generation can be integrated in the grid with little or no additional cost to utilities and their customers and without causing any adverse grid impacts. In fact, our study shows that at such levels, impacts due to PV generation are either non-existent or can be addressed by appropriate circuit operational changes.”Tweet