The 10 most popular blogs on Energy-Storage.news during 2019 offer a fairly strong indication of the overall topics leading industry thinking during the year – so without further ado, here they are:

Flow batteries have so far, failed to live up to the disruptive potential they promise, a new report says, but authors Alex Eller and William Tokash at Navigant Research have identified 12 leading vendors in the nascent field, based on metrics of strategy and execution.

California’s success in embracing renewable energy technologies, particularly solar, has brought with it challenges around reliability of supply to consumers. Janice Lin and Jack Chang of Strategen explore how the Golden State is pioneering the deployment of energy storage as it pursues its goal of complete energy decarbonisation by 2045.

As it prepares to break ground on a ‘Gigafactory’, energy storage system provider Tesvolt has said that gaining certification across diverse regions remains the biggest challenge in forming strategy today.

Solar Media, the publisher of sites including Energy-Storage.News and PV Tech, has just launched the latest edition of the annual Global Energy Storage Opportunity report for this year – available now as a free download.

As much as 40% of grid-connected battery storage projects that have been announced worldwide propose co-location with solar PV, from a pipeline of more than 10GW, analysts at IHS Markit have said.

While acknowledging that the economics “vary significantly” by region and application, Navigant Research has forecast that energy storage for integration of renewables and co-located with solar or wind could be worth more than US$20 billion by 2026.

While lithium-ion is rapidly racing ahead to become the “de facto grid storage solution” and is the most popular technology choice by far, vendors of other types of batteries are also targeting the market, with varying degrees of success.

To date, Primary Control Reserve (PCR) has dominated the energy storage debate in Germany with more than 100MW of battery storage installed in 2016 alone specifically for participating in the PCR market. At the same time, with close to 25,000 systems sold in 2016, residential storage has been stealing the limelight in the behind-the-meter segment. Julian Jansen of Delta-ee looks at how his team expects the commercial and industrial (C&I) segment to start catching up.

While Germany is one of the world’s leaders in solar PV and now an early leader in residential energy storage, utility-scale energy storage is still “under discussion” and not yet a mature proposition, industry figures have said.