What has COVID-19 taught us about decarbonized electricity grids?

This article is brought to you thanks to the collaboration of The European Sting with the World Economic Forum.

Author: Luis Badesa, Research Associate, Imperial College London & Goran Strbac, Professor of Electrical Energy Systems, Imperial College London

• In early 2020, COVID-19 lockdowns led to reduced electricity demand around the world.

• In Great Britain, the majority of the demand was covered by renewables, but this generation mix temporarily compromised the stability of the grid.
• These insights into a future of decarbonized grids highlight the challenges we face but also how we might solve them.

COVID-19 is a harsh reality that we are all still living with. But interestingly, this unprecedented situation can teach us valuable lessons about a service that has little to do with healthcare: electricity. A case of particular interest is Great Britain, an island that experienced a severe lockdown from 23 March 2020 which lasted for almost three months. The lockdown had an effect never seen before on the electricity system: zero-carbon sources were by far the main source of power.

This first lockdown – Great Britain is now coming out of its third – was a record-setting period. Great Britain saw the lowest national demand ever recorded, 13.4GW overnight on Sunday 28June 2020 (in comparison, the lowest demand in 2019 was 18GW). Also, the lowest carbon intensity ever, on 24 May 2020, when just 46gCO2/kWhwere produced on the transmission network. And the longest coal-free period since the industrial revolution, 68 consecutive days from April to June 2020.

Renewables and nuclear plants were the main sources of generation during lockdown. This was due to the drop in demand, which caused a subsequent drop in prices in the wholesale electricity market. Renewables and nuclear are somewhat indifferent to prices, as they have low or even zero fuel costs. But operating an electricity system simply relying on renewables and nuclear units is not currently feasible. This generation mix lacked flexibility.

What’s the World Economic Forum doing about the transition to clean energy?

Moving to clean energy is key to combating climate change, yet in the past five years, the energy transition has stagnated.

Energy consumption and production contribute to two-thirds of global emissions, and 81% of the global energy system is still based on fossil fuels, the same percentage as 30 years ago. Plus, improvements in the energy intensity of the global economy (the amount of energy used per unit of economic activity) are slowing. In 2018 energy intensity improved by 1.2%, the slowest rate since 2010.

Effective policies, private-sector action and public-private cooperation are needed to create a more inclusive, sustainable, affordable and secure global energy system.

Benchmarking progress is essential to a successful transition. The World Economic Forum’s Energy Transition Index, which ranks 115 economies on how well they balance energy security and access with environmental sustainability and affordability, shows that the biggest challenge facing energy transition is the lack of readiness among the world’s largest emitters, including US, China, India and Russia. The 10 countries that score the highest in terms of readiness account for only 2.6% of global annual emissions.

To future-proof the global energy system, the Forum’s Shaping the Future of Energy and Materials Platform is working on initiatives including, Systemic Efficiency, Innovation and Clean Energy and the Global Battery Alliance to encourage and enable innovative energy investments, technologies and solutions.

Additionally, the Mission Possible Platform (MPP) is working to assemble public and private partners to further the industry transition to set heavy industry and mobility sectors on the pathway towards net-zero emissions. MPP is an initiative created by the World Economic Forum and the Energy Transitions Commission.

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To obtain more flexibility, the energy system operator in Great Britain, National Grid ESO, took a number a “stability actions”. The most common stability action consists in turning on a number of gas plants, which increase the flexibility of the grid. These were plants that had not been successful in the wholesale energy market, since their cost was too high for the low levels of demand that we experienced. Therefore, National Grid had to re-adjust the generation dispatch so that it contained enough flexibility: in other words, gas plants were paid simply to make sure that Great Britain was able to always maintain the balance between demand and generation on a second-by-second basis, but not because they were needed to produce power. The total cost of these stability actions exceeded £300 million during Great Britain’s spring lockdown, a three-fold increase compared to the same months in 2019. This means that British electricity consumers had to pay a significant share of their bill for flexibility services, not for energy.

Fast devices like battery storage could solve future stability issues

But what exactly is this “flexibility” that is provided by gas plants but not by renewables? The key difference between these two types of generation is a simple concept: inertia. Inertia refers to the rotating masses in thermal generators (like gas and coal-fired power plants), which naturally store kinetic energy as they rotate to produce the power that we consume. These masses are therefore a valuable energy buffer, that spontaneously releases this energy if there is a sudden generation-demand imbalance. Renewables, on the other hand, do not naturally contribute to the inertia of the system, which is why they increase the challenge of maintaining the power balance in the grid. Inertia allows us to avoid blackouts, an ever more critical need as we become increasingly reliant on electricity.

In the future, procuring this flexibility will become even more expensive, as thermal plants will be scarce in a decarbonized system. As shown in Figure 2, stability actions could represent 15% of the total cost of operating the grid by 2030. But new devices like battery storage could provide much more effective stability support, as they are controlled by power electronics converters that can provide very fast power injections to the grid in the event of a generation-demand imbalance. Our recent studies show that a higher capacity of batteries providing support could drastically reduce the cost of stability actions, as shown in Figure 3. And not only the cost would be lower: we would avoid emissions related to stability, as turning on gas plants simply for inertia is not only expensive but it also pollutes significantly.

The COVID-19 lockdown demonstrated a clear change of paradigm in electricity grids: the future grids dominated by renewables and lacking inertia will have very fast dynamics, as compared to the past grids dominated by large thermal generators. This is both a challenge and an opportunity: changes will happen much faster, but we also have the chance to react to them much quicker. The future decarbonized grid will be fast like a Ferrari, unlike its predecessor which is more like a truck. This means we will need a fundamental change in the way we operate the grid: let’s take full advantage of our Ferrari and not drive as if it were a truck.