PNNL

As electricity grids incorporate renewables, several factors will constrain future output, and scientists point toward important avenues for future research to fully understand the challenges.

Electricity demand, climate change, and the limited availability of minerals and land for wind, solar, and transmission lines are among the biggest unknowns, according to a new paper published in the journal Springer Nature.

“Substantial research efforts are needed to improve the representation of geophysical constraints in computational models,” said study co-author Gokul Iyer, an Earth scientist at the Joint Global Change Research Institute (JGCRI), a partnership between Pacific Northwest National Laboratory (PNNL) and the University of Maryland.

More research into geophysical constraints will enable faster analyses, added co-author Thomas Wild, also an Earth scientist at JGCRI. “The additional research would expand the focus of grid decarbonization studies to include multi-sector impacts as well as elements of justice and equity,” Wild said.

Electricity demand is expected to increase, but the authors note that not enough is known about how climate change will affect that future demand. Nor is enough known about how minerals and land availability might affect the ability of future electricity systems to meet growing demands. “Additional efforts are needed to understand this uncertainty with future temperature projections, land, and mineral and material constraints taken into account,” Iyer said.

The authors note that future grids will likely be more decarbonized than today, tapping into hydropower, wind, solar, and bioenergy, while featuring an array of battery storage options.

All the current decarbonizing options, however, have potential constraints, the authors note.

Different requirements for different renewables

“Hydropower resources are mainly constrained by water availability, suitable topographic conditions, and availability of land for the construction of dams and reservoirs,” the study says.

Future wind and solar development, on the other hand, will depend on large-scale availability of land and water. On top of that, development of both energy sources will depend on obtaining minerals and materials that, in some cases, are available in only a few countries or regions. Another energy option, bioenergy, depends on the availability of land and water.

Better batteries, cheaper renewables—better future

The authors say that future decarbonized grids could be substantially constrained by geophysical constraints in their ability to meet growing demands. “At the same time,” Iyer said, “an encouraging development is that the cost of batteries and renewable technologies are going down. Understanding how these economic forces interact with future geophysical forces will be important to make wise decisions. And that in turn will require new data, methodological approaches, and enhancement of existing modeling tools.”

To cope with geophysical constraints, the authors recommend reducing the risks associated with power supply systems. One approach, they say, would be investment diversification, in which several power sources would reduce the risk of power shortfalls caused by geophysical constraints.

Also, with the increasing addition of renewable sources to the grid, the authors recommend continued development of energy storage technologies. “Energy storage should be seen as a portfolio of technologies that includes not only utility-scale batteries, but also other solutions such as flywheel and hydrogen energy storage,” the study said, adding that pumped-hydro energy storage has the potential to make a significant contribution.

In addition to Iyer and Wild, the study was led by AFM Kamal Chowdhury of the Earth System Science Interdisciplinary Center at the University of Maryland; and authors included Ranjit Deshmukh of the Environmental Studies Program and the Bren School of Environmental Science and Management, at the University of California Santa Barbara; and Stefano Galelli, of the School of Civil and Environmental Engineering at Cornell University.