In our pursuit of a sustainable energy future, we have seen great strides being made globally to transition from fossil fuels to renewable sources. In the UK, clean power generation is front-and-centre of the country’s strategy to reach net zero by 2050, with 43 cent of our electricity coming from a mix of wind, solar, bioenergy and hydroelectric sources this year.
The integration of more renewables is essential for net zero targets to be met. But the way in which these solutions come onto the grid must improve and accelerate in order to make the most of these clean energy sources, and to ensure security of supply in the face of a more complex system.
That’s where flexibility comes in; it’s the missing link to balance the energy system, given the more volatile supply and demand patterns and the location mismatch between generation sources and consumption centres. Flexibility allows green technologies to connect to our network in a way that does not exceed the physical limits of existing network infrastructure.
Grid flexibility has emerged as a crucial factor in shaping the changing energy landscape in the UK. The ESO’s Future Energy Scenarios (FES) report 2023 highlighted the different roles flexibility will play as a critical enabler in a successful energy transition, ensuring grid stability, and a decarbonised power system by 2035.
Four scenarios, one clear message
The UK has the largest flexible energy market in the world - a title it’s earned for the fourth year running - with network companies tendering for 3.7GW of flexibility in 2021/22.  The report lays out four energy scenarios that show the paths Britain could take to net zero. System Transformation, which highlights limited consumer change, and significant changes on the supply side to reach the 2050 target; Consumer Transformation, requiring material changes in consumer behaviour to reach the 2050 target; Leading the Way, which outlines world-leading transformation, with high consumer engagement and significant system changes, hitting our target early in 2046; and Falling Short, with our progression being too slow to hit our legally-binding net zero target.
One point is clear in all the FES report’s scenarios; with electricity demand in the UK expected to double by 2050, greater energy flexibility will be needed to balance supply with demand, whilst keeping network costs low. Some sources even say that a fully flexible system could cut the cost of reaching net zero by up to £16.7bn a year by 2050. 
Smart systems mean flexible systems
With our system changing so significantly, it’s clear system operators and consumers will need to work together in order to move to a net zero grid. This means behaviour will need to change, and data will need to be harnessed to ensure citizens can both reduce and manage their energy consumption. With heat and transport systems moving to electric, there is a huge opportunity for electric vehicles and smart heating systems like heat pumps to be used to enhance flexibility, using data and digitalisation to understand when these systems need to be turned up or down to manage demand.
Reducing curtailment and constraints
A range of key strategies can be implemented to ensure grid flexibility and reduce threats to an efficient energy system, such as curtailment. Between 2021 and 2023, £1.5 billion was used to curtail over 6.5TWh of wind power, not only costing billpayers but resulting in 2.5 million tonnes of emissions. This presents a significant threat to our progress and proves that the current energy system is not well-equipped to withstand surplus energy during peak generation periods. By improving locational flexibility at the distribution level – and our market signals – we can reduce costs and ensure progress towards net zero.
This is a proven model. Through its work with Piclo, the ESO’s new Local Constraints Market in Scotland is helping to manage grid constraints and reduce wind curtailment through creating a local marketplace that diverts extra wind power into local assets – benefitting people who charge the EVs, businesses with battery storage assets and even pumped hydro stations.
The future is flexible
Achieving net zero requires collaboration and commitment from all stakeholders, including policymakers, system operators, businesses, and citizens. The FES report highlights the pivotal role that energy flexibility will play in creating a green energy system and the immediate action we must take to avoid falling short.
James Johnston is CEO and co-founder of Piclo