Dr Holger Wolfschmidt from Siemens Energy explains why without the right quantity and energy storage mix in place, we won’t be able to stabilise the grid, decarbonise power generation, secure energy supply and make sector coupling possible.
Today, major organisations demand a massive rapid rollout of energy storage solutions, including setting clear targets for energy storage.
For instance, the European Association for Storage of Energy (EASE) states that energy storage targets “are a necessary complement to existing EU climate targets and will allow Europe to foster a local, sustainable green energy system independent of external energy imports. The EU urgently needs to adopt an Energy Storage Target and strategy to accelerate the necessary storage deployment today.”
Simply put: When it comes to our energy future, nothing will work without energy storage.
However, such statements from EASE and other organisations concerning energy storage still don’t get the public attention they deserve.
Today, increasing the share of renewables, mainly solar and wind, seems to be on everybody’s mind, along with the urgency of phasing out fossil fuels to reduce CO2 emissions and secure energy supply.
However, without energy storage to balance energy supply and demand, further expanding the share of renewables would not be possible, thus ultimately putting energy supply at risk.
This article is part of the ‘Future Energy Perspectives’ series, in which experts from Siemens Energy share their insights into how we can move towards a decarbonised energy system.
Aiming for 600GW energy storage capacity by 2050 in the EU
Also, power generation is becoming more and more decentralised while energy demand rises – and that also requires flexible energy storage.
Finally, sector coupling – transferring energy to other economic sectors – depends on expanding energy storage. All that explains why this topic deserves greater public attention.
Currently, we have around 60GW in energy storage capacity within the EU, mainly in the form of pumped hydro storage.
According to EASE’s estimates, at least 187GW by 2030 and 600GW by 2050 would be needed to enable electrification of various economic sectors while securing energy supply.
Moreover, it will ensure grid stability with the removal of inertia from the grid during fossil power phase-out.
No major technological hurdles
This means that the EU faces a formidable challenge: instead of 0.8GW installed in battery storage in 2020, 14GW of storage needs to be installed each year throughout 2030.
Without this, it’s possible that EU countries will have to curtail renewable energy generation and further rely on fossil power for dispatchable energy supply.
While these targets may seem to be a tall order, the good news is that the political will is there for creating a flexible decarbonised energy system on transmission as well as a distribution level.
And while R&D for various storage technologies will continue well into the future, there are currently no major technological hurdles standing in the way of implementing realistic measures now and reaching these goals sooner rather than later.
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Energy storage solutions as varied as their applications
In fact, all the different energy storage solutions available can be seen as a kind of Swiss Army knife, offering a great variety of solutions for different applications.
Some, such as supercapacitors, store electric charges with high-power density, and can thus deliver high energy within milliseconds, which greatly helps with grid fluctuations.
By comparison, batteries support grid stability as well as deliver dispatchable energy by discharging energy from milliseconds to hours to days.
Then there are mid-term mechanical solutions, such as compressed air storage that store energy for days or weeks, which can help balance the grid.
Finally, we have seasonal and even longer-term solutions, such as hydrogen, which enable shifting energy from the energy sectors to other parts of the economy, such as industry or mobility.
Batteries: flexible, mature, and multi-purpose
Let’s take a closer look at the classic solution for short-term energy storage: batteries, particularly lithium-ion batteries. As a flexible and mature solution, they serve a wide range of purposes.
Most importantly, they provide grid services, such as frequency regulation, serve in capacity markets, and can counter the volatility of renewable energy sources by storing energy whenever abundantly available, and provide it during shortages.
That’s particularly important for solar-dominated systems that require daily flexibility due to the day/night cycle.
Batteries have two additional benefits.
First, they help power producers or grid operators prevent a mostly involuntary reduction of energy output, also known as ‘curtailment’.
Second, they make energy arbitrage feasible. This means that producers can store energy when it’s cheap and sell it when prices are high.
When combined with renewables, such as wind farms, battery storage also helps manage power depending on current needs. They’re also well suited for black-start capabilities or as backup solutions.
For example, the Marsh Landing Generating Station, a gas-fired power plant close to Antioch, California, recently replaced its diesel engines for black starts with a battery solution.
Finally, microgrids for data centres and industry grids also need storage systems to enable flexible power usage.
Cancelling out battery shortcomings
As important as batteries are, they do have their shortcomings. On the one hand, rare elements are being used for their production, which raises environmental issues as well as concerns over the dependency on countries that supply them.
However, with continued research and development, rare elements could soon become less important.
Equally imperative is finding sustainable ways to either reuse or recycle batteries. We also need to develop new battery concepts.
For example, we need better solutions to help us be less dependent on and eventually replace lithium systems. One such concept is metal-free flow batteries, which may achieve longer discharge periods.
Overall, batteries are a great option, but not the only one. Other technologies can provide capacities they currently lack.
Mid- to long-term solutions for energy storage
When it comes to wind-dominated systems or those that can face ‘dunkelflaute’ (a period in which little to no energy can be generated due to insufficient wind and solar power), mid- to long-term storage solutions are vital. Capable of storing energy for days, weeks or months, they deliver energy when necessary.
Moreover, long-duration storage provides a great variety in terms of mechanical, thermal as well as thermal-mechanical solutions. One classic example of a mechanical solution is pumped hydro, which has been used for millennia and makes up over 90% of today’s global total energy storage.
By comparison, thermal energy storage adds another essential building block for any future energy system. It makes use of heat produced by renewable energy or captured from waste heat or exhaust gas, ranging in discharge duration and mid-term to long-term storage.
Various heat storage mediums are available in the form of liquids, such as molten salt and pressurised water, or solids, such as steel, concrete, or sand. These storage mediums enable the distribution of thermal energy across sectors back into various processes, including heating as well as cooling applications for buildings or industrial processes.
In short, storage solutions are indispensable for our energy future.
Long-term storage and smart controls
There’s one long-term storage technology we haven’t mentioned yet: hydrogen. It’s special in that it’s the most promising technology for enabling sector coupling.
Only by shifting renewable energy to other sectors, we’ll be able to decarbonise our economy, such as in buildings, mobility, industry, and other areas. Despite efficiency losses, hydrogen is the best long-term storage solution for renewable energy we have available today.
For sure, seamlessly integrating energy storage solutions into a future energy system won’t work without a smart control system that can integrate heterogeneous elements, such as renewables, energy storage, gas turbines and other assets, as well as projected demand and weather reports.
This means that, for instance, an optimiser can control dispatch based on weather forecasts, technical and financial measurements, and other parameters.
Defining energy storage targets
Based on energy storage assets, smart controls can also enable virtual grid expansion, storing as well as providing energy.
Moreover, they can digitally emulate the system inertia (so-called ‘grid-forming control’) required, as rotating mass leaves the grid – all of which can be controlled remotely and securely.
In short, storage solutions are indispensable for our energy future.
However, it takes much more than recognising that energy storage solutions are crucial for reaching an economy of net-zero emissions by mid-century. We must have the right political and financial measures at hand to ease the transition to a more sustainable energy system. At the same time, we need to define targets so that we know we’re on the right track.
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Complementary systems are essential
California, for example, set energy storage targets already in 2010 at 1.3GW by 2020 for the state’s investor-owned electric utilities. At present, it’s been increasing its targets with the goal of reaching 100% clean energy by 2045; today, the goal stands at 15GW.
However, that’s not enough. Recent estimates show that the state could need 55GW to reach that goal.
Such programmes are just the beginning, and we need to see more of these kinds of initiatives.
Around the world, we also need to foster close cooperation between policymakers and the private sector, as well as among companies competing for efficient and affordable energy solutions.
As the world aims to ensure a secure and decarbonised energy supply, it’s clear that a mix of complementary energy storage systems will be indispensable.
ABOUT THE AUTHOR
Dr Holger Wolfschmidt is Senior Portfolio Manager Storage at Siemens Energy.
Watch the exclusive interview with Dr Holger Wolfschmidt to learn more about his vision on the role of storage in the energy transition
