New clean generation technology is needed for the West to achieve 100 percent clean electricity
Energize Weekly, February 16, 2022
The West could run on 90 percent clean electricity by 2040 with existing renewable generation and storage, but to get to 100 percent, new, clean generation filling the same baseload and ramping capabilities done by natural gas-fired units will be needed, according to analysis by the Western Electricity Coordinating Council (WECC).
Once variable renewable generation (VRE) – primarily wind and solar – and battery storage reach 90 percent, “the benefits of further deployments are greatly reduced” mainly from a mismatch of renewable energy production and demand, WECC modeling found.
WECC promotes bulk power supply reliability and security for the Western Interconnection, which serves 14 states, the Canadian provinces of Alberta and British Columbia and the northern portion of Mexico’s Baja California.
High levels of wind and solar led to increased curtailments of generation when these resources produced more power than needed, while additional generation was needed when renewable generation declined and demand went up, as in shoulder periods at the end of the day.
“Storage must help compensate for the misalignment of hourly dispatches of VRE resources and hourly demand,” the WECC study said. “It must also provide resource flexibility that will be lost as gas-fired generation resources are displaced.”
The study found, however, that over 90 percent renewable generation the effectiveness of battery energy storage systems (BESS) is diminished without some other source for charging than renewable generation.
“The findings of this study suggest that BESS and VRE resources alone will not be enough to achieve a 100 percent clean energy future,” the study said.
What will be needed is emerging clean and flexible energy (ECF) technologies that have “performance characteristics similar to those of displaced gas-fired generation,” the WECC said.
“The results of the study indicate that clean energy above 90 percent will not be achieved economically and efficiently without including additional ECF candidate resources,” the study said. “No one can predict what new clean energy technologies may emerge by 2040 or what their performance characteristics will be other than to assert that they will be needed to achieve high levels of clean energy.”
In the WECC analysis, these new generation sources only have to fill a small portion of the energy mix.
In the profile for providing 1.6 million gigawatt-hours (GWh) for the region in 2040 at 90 percent clean energy, solar makes up 21 percent, wind 26 percent, hydropower 17 percent, pumped hydro storage and nuclear 1 percent each, batteries 12 percent, fossil-fuel generation 9 percent, other sources 5 percent, and ECF 8 percent.
To get to 100 percent, ECF has to increase to 16 percent of the total and batteries to 13 percent of the total electricity demand.
“Including a small percentage of ECF resources in the mix will go a long way toward mitigating many challenges that VRE resources introduce at higher levels of clean energy,” the study said.
Increasing variable renewable generation, VRE resources may also create transmission challenges. VRE penetrations above 90 percent, would, the study said, “significantly change the inter-regional flows in the Western Interconnection.”
In some cases, the changed flows result in some transmission lines being used at 90 percent to 100 percent of their rated capacities.
At 90 percent clean energy, the Great Basin, Southwest, Pacific Northwest and British Columbia would all be regions exporting electricity. California, Alberta and the Rocky Mountain West would be importers.
California would be, by far and away, the largest electricity importer, at 22,100 GWh for the year, followed by Alberta at 3,500 GWh. In a 100 percent clean energy scenario, California imports nearly double to 43,000 GWh.
