When utility customers first began adopting solar photovoltaic (PV) systems and connecting them to the grid, the number of customers deploying the systems was small, and the implication for the utilities was therefore minimal. Today, as costs come down and interest in renewable energy systems goes up, solar is spreading quickly.
Increasingly, PV system owners and vendors are quick to complain that utilities are throwing up roadblocks against interactions between solar and traditional power, especially in states like California and Hawaii, where the utilities’ relationships with renewables are not the same as they were 10 years ago. The utility, the argument goes, doesn’t want competition from renewables. In fact, some of the resistance we’re seeing from utilities today is about energy stability. Power companies have little choice but to look harder at how renewable energy affects their ability to deliver power reliably.
Dispersed energy sources and grid instability
Like the phone company, utilities are obligated to provide power to everyone in their service areas. To fulfill that duty, utilities historically managed dams, generation plants, and other power sources, along with the accompanying power transmission and distribution infrastructure. This gave them total control to match fluctuating supply and demand. Solar has become a disrupting influence in that process, particularly in areas with high levels of PV adoption.
As more solar system owners began connecting to the grid to supplement their own power generation and sell excess power back, the utility lost control over the balance between supply and demand. A neighborhood of PV owners essentially represents a distributed generation system to the utility. But if cloud cover rolls into that area and the generation system drops offline, the power plant needs to scramble to make up for the sudden shortage, and that disruption can have widespread effects.
In places where the greatest numbers of homeowners are filling their roofs with solar panels — California, Hawaii, and other sunny states — utilities have taken steps to limit interconnection. In these regions, where utilities initially expected a small portion of their subscribers to adopt renewable energy systems, a rapidly growing community of solar system owners is creating more energy than it consumes.
Creating a smarter grid
The very rules that allowed PV systems to be widely deployed have become a problem as more and more households adopt solar. With far more homes and businesses than once expected now generating energy, the utility often experiences hours of peak sun as high voltage conditions. This triggers a safety signal for grid-connected inverters to shut off. Thus, the utility faces frequent cycles of power disappearing and reappearing, creating additional problems for its customer base.
This is why utilities are pushing for a smart grid initiative. The California Energy Commission/California Public Utility Commission’s Smart Inverter Working Group is working toward new rules of grid-connected inverter operation, in which utilities gain the ability to communicate with smarter inverters to implement control strategies that improve grid stability and harness energy in predictable, reliable ways. Future-proof technology is critical to this process, and solar system manufacturers must get on board to create solutions that are less disruptive. The result will benefit not just utilities and their traditional power customers, but solar PV system owners as well.