Countries around the world are setting ambitious net zero targets for their energy systems. In parallel, many grid operators are taking steps to utilize demand-side flexibility: the ability of consumers and businesses to shift their energy usage to different times.

These two trends are related: demand-side flexibility is key to getting grids to net zero. Here are three reasons why deploying flex slashes CO₂ emissions.

Flexibility helps soak up excess renewables

Generation from renewables is uncontrollable. We don’t choose when the wind blows and the sun shines, and when they do, power production spikes. This leads to a “lumpy” supply profile, where sometimes we have more energy than we need.

We could just throw this energy away - this is called curtailment, and we actually do quite a bit of it in the UK. When this happens, the grid ends up paying people to produce less energy, which drives electricity prices negative. This is increasingly common: prices in the UK were negative for over 60 hours in April 2024, and Spain & Portugal recorded their first ever negative prices the same month.

A better idea: shift our energy consumption to match these peaks in supply. Like a squirrel stowing away acorns for winter, we can take advantage of these surges to top up our cars, fill our home batteries, and heat our water tanks. We don’t have to throw away any electrons, and the next time the wind dies we’re sitting pretty.

Flexibility can replace gas power in balancing the grid

Currently, fossil fuels play two roles in the electricity system:

• Generation: we burn coal and gas to make electricity
• Balancing: we rapidly dial gas plants up and down to match fluctuations in demand

It’s clear that renewables are displacing fossil fuels for generation. Solar and wind kWh are the cheapest in history. But you can’t use solar or wind power to balance the grid, because it’s hard to control how much energy they output.

You can exert this kind of control with flexible demand. Batteries, EV chargers, and heating systems can respond to small fluctuations in the electricity system in under 10 seconds. This delivers the one-two punch to fossil fuels: we use renewables to generate our energy, and rapid adjustments to demand to keep the grid in balance. A knockout combo.

Flexibility avoids costly infrastructure upgrades

The plummeting cost of batteries, government subsidies, and clean air programs are propelling electrification across the world. As we electrify transport, heating, and industry, we’re going to add a lot of load to the grid.

If all of these new devices draw power at the same time, peak load on the grid is going to grow substantially. Peak load determines the size of all our pylons, wires and transformers: we need to make sure nothing melts in the minute each year where demand is greatest.

Assumptions about peak load also lead to long waiting times for grid connections. Grid operators currently plan for a worst-case scenario - everything everywhere turning on all at once - and have to limit grid connections accordingly. The connection queue is currently clogging up the deployment of ~500GW of assets to the grid in the UK.

If we allow peak load to grow substantially, we’re going to need to rip out a lot of old infrastructure and deploy a lot of new copper, steel, and concrete.

That’s expensive, and it’s also really carbon intense. Making a tonne of copper metal emits ~4 tonnes of CO₂, and global cement production accounts for 7-8% of global emissions.

But peak load doesn't have to grow. We need to play energy tetris, filling in the dips in demands rather than piling new load onto the peak. By spreading out energy usage intelligently, we can limit the growth in peak load, and avoid replacing large parts of the grid.

This will be a good deal for users of the system, who won’t have to shoulder the costs of these upgrades - and it’ll save hundreds of thousands of tonnes of CO₂.

Conclusion

Flexibility and decarbonisation go hand in hand. In fact, it's impossible to boot fossil fuels from the grid without increased flexibility in how we use electricity.

Axle builds software to harness EVs, heat pumps and batteries to provide this flexibility. We already orchestrate tens of thousands of devices, automatically fulfilling grid requirements and earning revenue for their owners.

We’re also hiring. If you like moving fast, and you want to work on the biggest bottleneck to decarbonisation, join us!