When discussing the incorporation of renewable energy into the electricity mix, critics frequently mention the intermittency of renewable energy. What are they talking about? The term intermittency refers to the fact that renewable energy sources, such as solar or wind power, produce energy only when the sun shines or the wind blows. Therefore, it is harder to guarantee a constant flow of energy, than if you use fossil fuels or nuclear power for electricity generation. Because the grid’s storage capacity is limited, we must constantly maintain a balance between electricity demand and supply to avoid a blackout. So how can we overcome this intermittency and adjust energy demand to customers’ needs? 1 In this blog post, I’d like to talk about technical solutions for intermittency in renewable energy.
Outline of the post: This post will cover energy storage solutions like batteries, pumped hydro storage, and hydrogen storage, as well as grid-integrated solutions like smart grids and grid management systems. Finally, I will discuss how artificial intelligence, machine learning, and blockchain-based energy trading can be technical solutions for intermittency in renewable energy.
Energy Storage Solutions to Tackle Intermittency
Energy storage is one option for overcoming intermittent renewable energy and avoiding blackouts. In general, various energy storage technologies are available. One possibility is to store excess electricity from peak times of energy production in lithium-ion batteries, as California-based Vistra Energy does. Because of Vistra, California is regarded as a global pioneer, when it comes to high-capacity batteries. This company has the world’s largest energy storage capacity, capable of saving 400MW an energy equivalent that can power 300 000 households. 2 3
Pumped storage hydropower is a more resource-efficient alternative to battery-based energy storage. This storage system is made up of two reservoirs at different elevations. As water flows through a turbine from the higher to lower level, the difference in elevation can generate power. During peak times, water is pumped up to a higher elevation reservoir, which acts as a giant battery. 4
In a nutshell, energy storage can help overcome intermittency in renewable energy by storing excess energy generated during periods of high production and releasing it when demand is high or production is low. This helps to balance the supply and demand of electricity and ensure a reliable and stable energy supply.
Hydrogen Storage to overcome intermittency
In addition to batteries and pumped hydro-storage, we can use hydrogen storage to overcome intermittency in renewable energy. Electrolysis is one method of producing hydrogen. In this process energy splits water into oxygen and hydrogen. 5 In the case of solar panels, this means that energy excess during the day is used for electrolysis to generate hydrogen. This hydrogen can later be re-electrified during the night or during cloudy hours, with a loss of energy efficiency.
The fact that hydrogen has a high energy density per mass makes it especially attractive in comparison to lithium-ion batteries. One kilogram of hydrogen can store 40 000 Wh, compared to 278 Wh in the best lithium battery. Unfortunately, this technology has drawbacks because it requires a lot of energy to compress or cool the hydrogen to make it suitable for transport. 6 If you want to learn more about hydrogen’s advantages/ disadvantages for energy storage and upcoming trends, I recommend watching this video.
Grid Integrated Solutions against Intermittency in Renewable Energy
Image Source: Stockmar, Bartz
Implementing smart grids can also be one of the technical solutions for addressing the intermittency challenge in renewable energy. By using smart meters and continuous data flow, smart grids enable the instantaneous adjustment of electricity supply to meet real-time demand. In this case, electricity does not only travel from power plants to consumers but in both directions via decentralized power grids. This means that consumers can also feed electricity into the grid, for example, through rooftop PV systems. To avoid overloading the grid, smart grids can control whether electricity must be stored in household storage units or in electric vehicles. 7
The grid is intelligent in the sense that sensors can detect small imbalances in the grid quickly. Furthermore, computers control these sensors, which can make automated changes to maximize efficiency. Nevertheless, I also want to mention one flaw of smart grids here, which is that their connection to computer networks makes them vulnerable to hacker attacks. 8
Renewable Energy Forecasting and Planning Solutions
Forecasting and planning solutions via machine learning can help us to optimize energy usage. Therefore, machine learning and data analytics are becoming increasingly important to overcome the intermittency of renewable energy sources. We can use machine learning for predictive maintenance, managing power grids, and energy demand prediction. By analyzing historical and real-time data, machine learning algorithms can predict equipment failures, balance power generation and demand, and optimize energy production. As a result, the machine learning can lead to efficient usage of energy and cost reduction. 9
Blockchain Solutions to Address Intermittency
A promising technical solution for intermittency is energy trading via blockchains, the same technology for trading bitcoin. What makes it so special in the energy market? We can use blockchain in energy trading platforms and increase the transparency and traceability of data. A blockchain records the ownership of the generator’s energy, which can then be traded in a secure manner by encrypting the data. Moreover, smart contracts can automate data collection and price settlements and therefore reduce energy transition coast. As a result, blockchains can enable decentralized coordination between energy trading participants and therefore increase energy access for many people. An example of a successful blockchain-based energy project is the Chiang Mai University P2P (Peer to Peer) system in Thailand, which allows for the trading of solar energy generated by 12 MW of rooftop solar panels on the university buildings. 10
Conclusion
Renewable energy is crucial to reduce greenhouse gas and protect ecosystems. However, the problem of intermittency, which causes fluctuations in energy supply, needs to be addressed to ensure a reliable and sustainable energy transition. In conclusion, technical solutions for intermittency in renewable energy include energy storage solutions such as lithium-ion batteries and pumped hydro-storage, hydrogen storage, smart grids, and machine learning for renewable energy forecasting and planning, and blockchain-based energy trading platforms. These technical solutions can help balance the supply and demand of electricity, ensure a reliable and stable energy supply, and lead to efficient usage of energy and cost reduction. However, it is important to note that some of these technologies have drawbacks, such as the energy requirements of hydrogen compression and cooling or the vulnerability of smart grids to hacker attacks.
If you want to learn more about actual trends and the future of renewable energy check out my latest blog post.
References:- Fares, R., n.d. Renewable Energy Intermittency Explained: Challenges, Solutions, and Opportunities. Scientific American Blog Network. URL https://blogs.scientificamerican.com/plugged-in/renewable-energy-intermittency-explained-challenges-solutions-and-opportunities/ (accessed 18.4.23).
- Vistra Corp., n.d. Vistra. URL https://vistracorp.com/ (accessed 18.4.23).
- Katz, C., 2020. In Boost for Renewables, Grid-Scale Battery Storage Is on the Rise. Yale E360. URL https://e360.yale.edu/features/in-boost-for-renewables-grid-scale-battery-storage-is-on-the-rise (accessed 18.4.23).
- Water Power Technologies Office, n.d. Pumped Storage Hydropower. Energy.gov. URL https://www.energy.gov/eere/water/pumped-storage-hydropower (accessed 18.4.23).
- Energy Storage Association, n.d. Hydrogen Energy Storage. URL https://energystorage.org/why-energy-storage/technologies/hydrogen-energy-storage/ (accessed19.4.23).
- Just Have a Think, 2020. Energy Storage in Hydrogen: Does this beat batteries? URL: https://www.youtube.com/watch?v=f6_OVfrc_5A (accessed 19.4.23).
- Sympower, n.d. Smart Grids Explained. URL https://sympower.net/smart-grid-explained/ (accessed 19.4.23).
- Scientific American, n.d. Decoded: What is a “Smart Grid” and how does it work? – YouTube. URL https://www.youtube.com/watch?v=X2eYdAR0ka4 (accessed 18.4.23).
- Daivi, 2023. 5 Modern Applications of Machine Learning in Energy Sector. URL https://www.projectpro.io/article/applications-of-machine-learning-in-energy-sector/770 (accessed 18.4.23).
- ESCSAP 75, n.d. Blockchain´s role in the energy transition: improving renewable energy adoption through distributed solutions. URL https://www.unescap.org/blog/blockchains-role-energy-transition-improving-renewable-energy-adoption-through-distributed (accessed 19.4.23).
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