As it stands, the power grid does its job well. It transports power from generation sites to consumers and, in most cases, it does so with consistency. The recent increase in adoption of solar, or photovoltaic, power generation has complicated things for this system of power transmission.
Historically, electrical current flows from central generators across the transmission grid to distribution circuits and ultimately serves load at the end customer site. Grid assets are built to accommodate peak customer load and to manage the volatility in demand at each level of the grid. The system was not built to manage uncontrolled two-way traffic safely or to import significant generation at distribution voltages.
Further, PV output is highly volatile, capable of changing output by over 80 percent within a few seconds.
Imagine a solar customer that is exporting power at 2 p.m. despite a large HVAC load. If a cloud interrupts solar production, the customer rapidly becomes a large power consumer; and when the cloud passes, the customer swings back again to being a generator. This volatility disrupts the flow of current on the distribution grid unpredictably and at high speeds, challenging the distribution system to manage voltage within mandated quality levels.
This doesn’t mean photovoltaic energy generation is the problem. The infrastructure of the grid is not flexible enough to allow for alternative sources of power generation or the two-way movement of electricity that results from it.
There are a few possible solutions to address the technical challenges from distributed PV volatility: curtail PV production, invest in more robust distribution grid infrastructure to support greater volatility, or solve the problem at the source by making customers accountable for the system effects of highly variable loads.
Limiting distributed PV development should not be an option, but without a solution to the volatility challenges, distribution utilities may have no choice. PV curtailment could work, but introducing such a mechanism would reduce PV production and jeopardize solar’s hard-earned bankability.
Utilities could also invest heavily in distribution grid equipment to guard against PV volatility. However, Germany offers a cautionary tale. While the wholesale price of energy in Germany is falling due to high adoption of wind and distributed PV, the retail price to customers has increased. The disparity comes from the infrastructure investment required to deliver high quality power in the face of increased volatility.
The third option is to solve the volatility problem at the source. If customers with erratic load or distributed generation were incentivized under a new “deal” to either smooth their load or pay for increased volatility, they would have the option to solve the problem themselves or pay the utility to do so. Customers already have a suite of products available to smooth their net demand if incentivized to do so through utility demand charges or even a newly defined “volatility charge.”
It’s important to know that the current state of the power grid does not account for adopting photovoltaic power generation. This means that we need to work on upgrading our infrastructure to accommodate for renewable power generation’s additions to the grid. Investing in upgrading and improving the grid, both from the consumer side and utility side, is important to the future of the grid itself.
To read more on how to alter the power grid, read the article here http://www.greentechmedia.com/articles/read/Solving-the-Next-Grid-Challenge-Volatility