New York’s climate goals are some of the most ambitious in the country, with the State’s Climate Leadership and Community Protection Act mandating 70 percent renewable energy on the grid by 2030 and 100 percent carbon-free electricity by 2040. The challenge for New York is to determine how to meet these goals quickly and cost-effectively, while still maintaining grid reliability.
Several studies have analyzed cost-efficient pathways to achieving New York’s decarbonization and reliability targets, and all have identified a need for 20 to 45 gigawatts (GW) of “dispatchable, emissions free resources” (DEFRs) that provide sustained, on-demand power to the grid. However, those studies did not examine which technologies in the broad category of DEFRs would provide that service at the lowest cost. Using Formware (TM), Form Energy’s grid modeling tool, the Software & Analytics team analyzed which portfolio of technologies would cost the least for New York to meet its 2030 and 2040 clean energy goals and fulfill its needs for DEFRs. This analysis included a diverse set of emerging technologies, with a focus on long duration energy storage (LDES) with durations of 10-24 hours and multi-day energy storage (MDS) with durations of 24 hours or more.
Form Energy recently published findings from its analysis of the NYISO market in a white paper, Modeling Multi-Day Energy Storage in New York: Storage Portfolios That Can Enable a Reliable, Zero-Carbon Grid. Broadly, our analysis found that emerging long-duration and multi-day energy storage technologies can drive down costs and reliably integrate renewables in New York’s clean energy future. The study modeled least-cost investments to meet New York’s goals and resulted in three key findings:
- Approximately 3-5 GW of diverse LDES and MDS technologies are part of a least-cost total resource portfolio in New York in 2030. This amount increases to 35 GW by 2040.
- LDES and MDS technologies reduce the cost of achieving the State’s decarbonization targets by approximately 6% in 2030, and almost 30% in 2040. They reduce the amount of new renewable generation resources and short-duration storage systems that New York will need, and shift renewable energy from periods with excess supply to periods with insufficient supply – both of which drive savings in total system cost.
- Least-cost portfolios for New York in both 2030 and 2040 have an order of magnitude more capability to store gigawatt-hours (GWh) of energy when LDES and MDS are included in resource planning. That capacity can support the grid during periods of low renewable generation. It can also soak up energy during periods of excess generation, reducing the need for renewable curtailment.
Installed Capacity and Annual System Costs (New York, 2040)

Overall, dispatch modeling with full-year chronology shows that multi-day energy storage provides flexible, dispatchable, emission-free capacity over the hourly, daily, and multi-day time-scales necessary to balance the variability of renewable energy on New York’s grid. These resources can support system resiliency during lulls in renewable generation, and extreme summer heatwaves and winter storms lasting multiple days.
To realize the opportunities of LDES and MDS, New York will need to deploy on average at least 3 GW per year of these technologies between 2030 and 2040. Near term policy support will be needed to build the market for these emerging technologies. Through NYSERDA’s long-duration energy storage grant program, New York is already investing in opportunities to expedite commercialization of LDES and MDS – including a 10 MW / 1000 MWh demonstration project of Form’s multi-day iron-air battery system.
To learn more about the results of our analysis, please see our white paper, Modeling Multi-Day Energy Storage in New York, available at the link here.