https://pagetwo.completecolorado.com...nt-renewables/

In what can only be described as revealing (and unsurprising), a 2019 March presentation by Xcel Energy supports our concerns about the cost of transitioning to 100 percent renewable energy.

To prevent ratepayers from curtailing their daily electric usage, Xcel believes it will need eight to sixteen weeks of storage capacity. Keep in mind, this projection is based on its current footprint of 3.6 million electric customers living in service areas throughout eight states. Nevertheless, if Xcel Energy is to build enough storage to cover peak demand (2020 projections from Northern States Power, Public Service Company, and Southwestern Public Service) and last at least eight weeks (which is the low-end estimate) it will need to have close to 27 million megawatt hours of battery storage installed and online to prevent curtailment and maintain the status quo.