Energy flexibility and its role in the future of renewables

James Murdza
4 min readNov 7, 2022


Summary: Renewable energy production follows the rhythms of the weather, not human consumption. Supply and demand must be kept in balance with a flexible energy system. An area with a lot of space for innovation is demand side flexibility — i.e. ways to consume less when prices are high.

If there is a good time to accelerate the transition to renewable energy in the UK this might be it. The dangers of climate change have finally reached widespread awareness and energy prices are going wild due to geopolitics. Of course the transition requires upgrading our methods of electricity generation, but how will that affect the system as a whole? Can we withstand the unpredictability that comes with tying our energy to the sun and wind?

Wind turbines. Credit: EDF Energy

In the past month I interviewed 40 people on the theme of energy flexibility, working along with my partner Eugenio Lupi in the Entrepreneur First startup program. It would be a waste not to share some of the things that we learned! So in two short articles I am planning to cover:

  • Part I: Why flexibility is key to the renewables transition
  • Part II: How commercial buildings can participate in flexibility markets

A typical day of energy usage

It’s a beautiful morning right now in the UK with wind farms providing a bountiful 18 gigawatts of the nation’s electricity needs. Later today as millions of people return home from work and switch on their lights, laundry and television, the total need for energy will increase. It’s nice and windy now but what if the wind dies down in the evening? More electricity will be needed, while less is available!

The chart below from the energy provider Octopus shows day-by-day patterns of total energy demand and supply of renewables. Despite a fairly regular pattern in energy usage, the renewable energy might supply anywhere from 10 to 90% of that depending on the day and time.

Illustrative example of renewable supply and energy demand. Source: Octopus Energy.

The role of flexibility

National Grid ESO is always carefully monitoring the frequency of the AC signal in the power lines to sense when things may be going out of balance. Making use of real-time data and forecasting, it can plan the ramping up and down of energy as the price varies. This ability of the grid to stay in balance is called flexibility.

Flexibility in a nutshell.

Any energy consuming or producing asset can contribute to flexibility if it responds to energy prices as the diagram above shows. Conventionally, the largest source of flexibility in our grid is gas turbine power plants. They can reliably be turned on and off, despite being inefficient and very carbon intensive. A more modern approach is to use batteries for flexibility. Batteries are also highly reliable and more sustainably, however batteries are expensive. There is no perfect solution—creativity is needed to solve the flexibility problem as a whole.

A battery pack is an example of energy flexibility. Source: Tesla

The future of flexibility

As our energy system develops, large amounts of flexibility will need to be added quickly. Need for flexible electricity storage in Great Britain alone is expected to increase from 1.6GW now to 15GW¹ in 2030 and 35GW in 2050 according to National Grid ESO². Keep in mind that each flexibility source has a power rating, total energy capacity, and ramp-up time, which means that a variety of types of flexibilities sources will be needed to make this useful.

How can the United Kingdom’s electricity market be equipped with this needed flexibility? Four general ways to make the electricity grid more flexible are:

  1. Store energy when the price is low. Return it when the price is high. This includes any electrical storage in homes or at the grid level, such as lithium-ion batteries, hydrogen, compressed air energy storage, thermal batteries, and vehicle-to-grid.
  2. Move energy to where the price is higher. This means investing in stronger transmission and distribution systems, and systems for cross-border energy trading.
  3. Provide energy when the price is high. This can be any generator that responds quickly, such as open-cycle gas turbine (OCGT) power plants.
  4. Consume less energy when the price is high. Also called demand side flexibility, this is applicable to high energy consuming processes such as non-critical factory production and HVAC systems.

In the next post, we will explore demand side flexibility further, and how commercial buildings are an untapped source of flexibility that will be needed by the end of this decade.


[1] The 15GW in 2030 figure given is only for battery storage, so the true number may be a bit higher.

[2] The numbers all come from National Gride ESO’s Future Energy Scenarios key insights and full report.