(1) “Global Storage Market to Double Six Times by 2030,” Bloomberg New Energy Finance, November 20, 2017, https://about.bnef.com/blog/global-storage-market-double-six-times-2030.
(2) Energy Storage Association, “Facts and Figures.” Energy Storage, Accessed March 23, 2018, http://energystorage.org/energystorage/facts-figures.
(3) Frankel, David and Amy Wagner, “Battery Storage: The Next Disruptive Technology in the Power Sector,” McKinsey & Company, June 2017, www.mckinsey.com/business-functions/sustainabilityand-resource-productivity/our-insights/battery-storage-the-nextdisruptive-technology-in-the-power-sector.
(4) Deign, Jason, “Stories That Defined the Global Energy Market in 2017,” Greentech Media, December 15, 2017, www.greentechmedia.com/articles/read/stories-that-defined-global-energystorage-in-2017.
(5) Spector, Julian, “Italian Utility Enel Acquires Energy Storage Specialist Demand Energy,” Greentech Media, January 11, 2017, www.greentechmedia.com/articles/read/italian-utility-enel-acquiresenergy-storage-specialist-demand-energy#gs.JtwCJjg.
(6) St. John, Jeff, “European Grid Edge M&A Alert: Centrica Buys REstore for $81M,” Greentech Media, November 3, 2017, www.greentechmedia.com/articles/read/european-grid-edge-ma-alertcentrica-buys-restore-for-81m#gs.aeN5nK0.
(7) St. John, Jeff, “Was 2017 the Year Global Energy Giants Went All-In on the Distributed Energy Revolution?” Greentech Media, December 28, 2017, www.greentechmedia.com/articles/read/the-year-incleantech-energy-storage-and-grid-edge-ma.
(8) Chediak, Mark, “World’s Deploying More Batteries Than Ever – But Slower,” Bloomberg Technology, February 13, 2018, www.bloomberg.com/news/articles/2018-02-14/world-s-still-deploying-more-batteriesthan-ever-but-slower.
(9) Ram, Manish et al, “Global Energy System Based on 100% Renewable Energy—Power Sector,” Energy Watch Group, November 2017, http://energywatchgroup.org/wp-content/uploads/2017/11/FullStudy-100-Renewable-Energy-Worldwide-Power-Sector.pdf. It is important to note that the deployment of energy storage alone may not ultimately result in a reduction in emissions. In fact, if proper policies and market signals are not put into place, storage can even increase emissions in some scenarios. For example, a 2017 study (See, Goteti, Naga Srujana, “How Much Wind and Solar are Needed to Realize Emissions Benefits from Storage?” Energy Systems, p. 1–23, December 11, 2017, https://link.springer.com/article/10.1007/s12667-017-0266-4) found that deploying storage on a coal-heavy grid could increase emissions. For this reason, we stress the pairing of renewables and energy storage to achieve emissions reductions. It is that combined policy regime that is needed to move the market.
(10) There is an ongoing debate on this topic among environmental colleagues. David Roberts has summarized the literature on this topic reasonably well. (See, Roberts, David, “Is 100% Renewables Realistic? Here’s What We Know,” Vox, April 17, 2017, www.vox.com/energy-and-environment/2017/4/7/15159034/100-renewableenergy-studies.) Much of this debate is a one among climate colleagues who are modelling various scenarios to get to a fossil fuel-free future, so it’s important to take their efforts seriously. Some have concluded that a renewables-only future is not a reasonably cost-effective solution, and they argue for a broader suite of alternative low carbon technologies, including nuclear and carbon capture and storage (CCS). They may well have an argument, that delivering reliable power through a 100% renewables future alone may not be economically feasible, but the studies underlying these scenarios, when it comes to energy storage often: (1) rely on the wrong technology, such as pumped hydro rather than batteries technologies, to project future costs that turn out to be too high to be meaningful, or (2) rely on the wrong costs for battery storage either by ignoring current cost reduction pathways, or by failing to acknowledge the many cost saving and revenue generating opportunities for batteries in electricity markets. In either case, these studies often result in conclusions that inflate the future costs of storage as a cost-effective option with renewables to reduce emissions, thus making the non-renewables alternatives look more cost-effective by comparison. What’s more, the studies often fail to distinguish between situations where battery storage could support major renewables integration with shorter-term duration storage technologies, as compared to much longer-term duration, seasonal storage needs not feasible with today’s battery technologies.
However, a recent relevant study by Nathan Lewis at Caltech (with Matthew R. Shaner et al) is an important advance toward more sensible projections in this field, especially about the role of energy storage in future renewable integration scenarios. (See: Shaner, Matthew r, et al, “Geophysical Constraints on the reliability of Solar and Wind Power in the United States,” Energy Environ. Sci., 2018, The Royal Society of Chemistry, February 27, 2018, DOi:10.1039/c7ee03029k, http://pubs.rsc.org/en/content/articlelanding/2018/ee/c7ee03029k#!divAbstract). The study concludes that renewables systems with batteries that can store solar electricity for 12-hour durations could reliably meet up to 80% of the electric power system demands by 2050; that alone is an extraordinary finding – achieving an 80% renewable energy system with existing lithium-ion storage technologies. Battery projects now being bid into market are committed to delivering up to 10-hour durations; getting to 12-hour durations is a reasonably achievable, incremental economic improvement. The study concludes that to go further and reach a 100% renewables scenario, more longer-term, seasonal storage is needed, and that is not now economically feasible. (See the “Emerging issues” section on “Power to Gas” for a discussion on this long-term storage technology issue.)
The debate over the findings from these types of studies is a critical one about whether renewables and energy storage could reliably replace fossil-fuel baseload plants in the future and bring about a decarbonized energy sector. Regardless of the conclusions the studies reach, recent finding all appear to confirm one critical point: getting the energy storage solution right is a key linchpin to answer the question whether a future energy system can be powered by renewables at significant levels. Unlike the approach of some studies, the solution is not likely to be an either/or answer, but a continuum of time durations where existing and future combinations of storage technologies can provide support to various future levels of renewables integration. As noted elsewhere, this paper is not written to grapple with this complete fossil-fuel replacement problem in any detail. Instead, it has been written to point out that, if storage is so critical to these long-term, future solutions, more work must be done now to reliably study and analyze current trends in cost and performance of battery technology to support a more robust and honest debate about storage’s role in enabling renewables integration in future climate emissions scenarios.