Storage is the key to the renewable energy revolution

Governments and corporations alike have set aggressive sustainability goals that they must hit over the next decade to reduce the effects of climate change. As such, there has been significant investment in the energy transition to renewable sources.

But reliance on renewable generation alone is an incomplete solution for grid-supplied energy. Here’s why — and what we should do about it.

First, renewable generation faces intermittency and curtailment issues. That is to say, renewable sources only generate when the sun is shining or wind is blowing, while at others times too much energy for the demand level is generated by these sources, causing waste. Second, renewable energy generation does not solve issues stemming from severe weather conditions, where grids may shut off and insufficient energy is generated during supply and demand shocks.

Long Duration Energy Storage (LDES) could be the solution to these limitations of renewable energy.

LDES systems integrate with renewable generation sites and can store energy for over 10 hours. e-Zinc’s battery is one example of a 12–100-hour duration solution, with capabilities including recapturing curtailed energy for time shifting, providing resilience when the grid goes down and addressing extended periods of peak demand to replace traditional peaking power plants and transmission and distribution infrastructure.

To understand how LDES can transform energy grids, it’s important to understand what the problem of energy storage looks like in practice.

Curtailment creates waste today, but is also a significant opportunity if we can conserve that energy for when we need it. The New York Independent System Operator, which monitors the reliability of the state’s power system and coordinates the daily operations to distribute electricity supply, saw 64 GWh of wind generated energy curtailed, wasted, in 2021. This is equivalent to powering 12,000 homes for an entire year. Meanwhile in California, the issue is magnitudes larger — 1.9 TWh of solar generated energy was curtailed in 2022; the equivalent of powering 200,000 homes for an entire year. The Southwest Power Pool, a considerably smaller market for renewable buildout, curtailed 7% of all wind generated energy (9 GWh) in 2022.

An LDES solution would have captured the excess energy generated during these otherwise curtailed periods, and shifted it to times of greater need — periods of intermittency, grid shut offs or periods of peak demand, for example to replace peaking power plants and transmission and distribution infrastructure.

Due to climate change, seven of California’s 10 most destructive wildfires have occurred in the past decade. In 2014-2019 alone, 7,900 wildfires resulted in an annual average of $590 million worth of damage, burning 1.2 million acres and destroying 1,300 structures. One method of reducing these wildfires is through a Public Safety Power Shutoff (PSPS), where grids turn off power during severe weather to prevent equipment damage that may otherwise ignite a wildfire. In 2021, 38 PSPS events lasted longer than 2 days, with the longest lasting nearly 8 days. Data from 2022 is still being finalized, but the longest recorded lasted 31 hours.

During winter storm Uri in February 2021, Texas electricity prices spiked to $9,000/MWh. Prices remained at around $6,500/MWh for 80 hours because of the failure to bring additional supply to the grid. This contributed to the 700 deaths and $38 billion in excess energy costs for ratepayers. In a less extreme case, in July 2022, a record heat wave caused the Electric Reliability Council of Texas North prices to spike to an average of $182/MWh compared to the $50-$100/MWh average throughout the rest of the year.

In California and Texas, customers with high reliability needs — data centres, hospitals, telecoms companies, for example — require multiple days of resiliency and thus rely on diesel generation for backup power during severe weather events, which furthers the issues of climate change. LDES solutions would have been able to provide backup power during these grid shut-offs and extreme price spikes, preventing the reliance on diesel generators and ensuring accessible and affordable energy.

An analysis conducted by the LDES Council and McKinsey & Company found that once a grid hits 60-70% renewables, LDES becomes mandatory for an efficient grid. Grids in parts of California, New York, Texas, Germany and the UK are on track to hit this threshold by the late 2020s or early 2030s. Even in regions such as the Electric Reliability Council of Texas, where there are no renewable mandates and targets, renewables already supply 34% of its electricity with no signs of slowing down.

Major utilities have caught on to the importance of LDES systems when considering their investment in renewables. This year, Xcel Energy has launched a request for proposals for solar and battery storage projects to replace retiring coal plants. PNM is replacing an 847 MW coal plant with 650 MW solar power paired with 300 MW/1,200 MWh of energy storage. Vistra and NRG are replacing coal plants in Illinois with solar generation and storage solutions. These power plants run around the clock in many cases and thus cannot be replaced with incumbent energy storage solutions, which at best can provide 4-6 hours of storage. Investment in LDES solutions will ensure that these utilities provide affordable and reliable, consistent energy with a clean grid.

The international community is making significant progress toward hitting its ambitious climate targets, particularly when it comes to investment in renewable energy. To take this progress a step further, LDES development and integration is essential. Unlocking a more sustainable and healthy future for communities, and providing reliable and affordable energy, is the ultimate goal — LDES is the key.