Comment: Standardising solar and storage

Troy Miller

Ten years ago, the cost of battery energy storage was high, the installations were unproven, and the risks could have been detrimental to hopeful energy storage integrators. We have come a long way since then, says Troy Miller.

Technological innovations have paved the way for greater amounts of storage to be integrated on the grid. When paired with installed renewable capacity – more often than not, solar installations – the benefits are endless.

We are at a point where solar generation and battery energy storage deployments are nearly at parity when compared to traditional forms of generation. We have the facts and figures to show the success rates of integration, but we are still in the infancy of overall solar and storage adoption. Through this pairing, developers and utilities are able to harness more renewable energy, utilise it during peak times and provide a more reliable grid for end users, all while contributing to a smaller, cleaner carbon footprint.

This leads to the question, “What’s stopping solar developers from moving forward with the addition of energy storage?”

As battery costs continue to fall, solar and storage projects are likely to become more prevalent throughout our grid. While solar generation sites have become an integral part of the grid, adding energy storage is a proven way to increase a developers’ ROI, add valuable experience for the industry at large, and continue to better support end users on the grid. With so many cities, states, and countries looking to meet aggressive renewable energy goals over the next few years, developers need to not only be looking for a location to build up their generation, but a way to maximise its potential.

Successes to date

We have made great leaps forward, but there is still a long way to go before the industry is using solar and storage to its fullest extent, especially in adding storage to pre-existing solar deployments. That said, there are a number of strong examples throughout the US, like the Village of Minster Solar + Storage Project in Ohio. The Village of Minster already had a functional solar generation site, but with the help of developer Half Moon Power, they were able to increase the functionality of the site by adding energy storage. Municipal utilities, like Minster, in conjunction with solar developers, are also recognising the additional revenue streams garnered when they pair solar generation with battery energy storage. For Minster in particular, the developer is benefiting from frequency regulation revenue from PJM plus the Village can now boast having one of the most reliable grids in the state of Ohio.

Along with the rise in developers adding storage to pre-existing solar, we are also seeing an influx of new project developers building solar+ storage systems from the ground up. It is only a matter of time before a standard is set to install solar and storage simultaneously across the board.  The benefits of both outperform those of just one (solar or storage) on their own. Utilising both solar and storage allows developers to maximise value and future-proof their installations.

Ameren Illinois, a regulated electricity-delivery company whose parent Ameren Corporation serves 2.4 million electricity customers, was interested in building two microgrids at its Technology Application Center near the University of Illinois’ campus to support the center and a 1-MW residential load.  Ameren was interested in testing out more than 20 different use cases on their microgrid, one of the most important of which was the ability to “black start” the microgrid and be able to return to the grid from island mode without an outage occurring.

The project involved creating both a 50-kW microgrid and a 1-MW microgrid.   The components of the microgrid included a 100-kW wind turbine, a 125-kW solar array and two 500-kW natural gas generators as additional alternative energy sources.  Most importantly, S&C provided a 250-kW/500-kWh energy-storage system that served as the backbone of the 50-kW microgrid.  Plus, the wind and solar don’t have to be curtailed in the microgrid, and can even exceed the load because the PureWave SMS-250 can be put into charging mode while still providing the microgrid reference frequency and voltage.

What’s next?

Peaker plants are traditionally utility-built generation sources that are only utilised during the few days a year the grid is the most heavily loaded. They could potentially sit idle as many as 350 days a year. These types of generation sites provide necessary generation at high demand times, but they are inefficient during off times. Could we do better than this?

Many states are making strides to change their grids and the way their citizens consume energy with the addition of energy storage. Maryland and Vermont currently have Bills within their state congresses to study energy storage benefits further, and begin to develop tax initiates for deployment.

Nevada, New York and Massachusetts are in the process of setting energy storage procurement targets within their utility plans. Washington has already begun including energy storage within the state’s integrated resource plan.

Oregon has a ten-year plan in place to add energy storage to the grid. Hawaii just announced a bill that will increase tax credits on energy storage through 2023, and California has doubled the total budget that goes towards the completion of energy storage projects – the list goes on.

With the recent NOPR ruling, FERC is leveling the playing field for energy storage. Backlogged connection queues in the ISOs and RTOs currently do not benefit storage, either as stand-alone facilities, or those co-located with other generation. The FERC proposal will likely improve the certainty, transparency, and process to allow storage developers to better identify opportunities for solving congestion problems, particularly when it is coupled with other forms of generation, like Solar PV. Energy storage systems are also fuel neutral and help any generation resource connected to the grid – whether fossil or renewable – become more efficient, productive, and competitive. 

With the further deployment of solar + storage installations, utilities could help avoid the stranded capital that is inherent with peaker plants, while simultaneously providing more reliable generation assistance to their grid.

There is a growing demand for reliable energy supply. Solar + storage needs to be considered as reliable “dispatchable” generation asset on par with more traditional forms of generation.  The technology is proven - it’s now up to developers and utilities to make these types of projects a grid standard.

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Energy storage including Fuel cells  •  Photovoltaics (PV)  •  Policy, investment and markets  •  Solar electricity