The world is on a narrowing path to achieving net-zero emissions by 2050.
The power sector is pivotal in global decarbonisation efforts, demanding rapid, large-scale transformation. Decisive action is needed now to ensure we choose the optimal way forward.
We compared two pathways from today to 2050 with the aim to reduce greenhouse gas emissions and limit global warming.
What might surprise you, is that net zero can’t be achieved with renewables alone.
Balancing power plants are key in scaling up renewable energy and crucial to reach net zero.
Compared to a renewables pathway, the deployment of balancing power plants reduces the total cost of future power systems by as much as 42%, approximately EUR 65 trillion.
Adding balancing power can reduce the total accumulated power sector CO₂ emissions by 21% by 2050 compared to the renewables path.
The use of balancing power allows for enhanced power system optimisation, resulting in 88% less wasted energy due to renewable curtailment by 2050.
Adding balancing power plants can halve the required renewable capacity and significantly reduce the land needed for infrastructure, which would otherwise cover an area the size of Europe.
Two potential pathways to net zero
We created a global power system model to evaluate the impact of two widely discussed decarbonisation pathways between today and 2050.
Can net zero be reached by adding only renewables and energy storage?
Let’s compare the findings.
This pathway relies solely on the expansion of variable renewable energy, namely solar and wind, and energy storage systems.
This pathway incorporates balancing power plants, e.g. flexible engine power plants, alongside renewable energy and energy storage systems.
The findings show that the Balanced pathway achieves net zero more cost-effectively, with projected savings of over EUR 65 trillion from 2025 to 2050 compared to the Renewables and storage pathway - equivalent to more than 60% of global GDP today.
This significant cost reduction is largely due to minimised curtailment and reduced renewable energy overcapacity enabled by the use of balancing power plants.
The Balanced pathway sees a rapid decline in emissions as inflexible assets are phased out and replaced by renewables supported by energy storage and balancing power plants. Consequently, this pathway achieves a near 21% (19 Gt) reduction in cumulative emissions by 2050 compared to the Renewables and storage pathway.
In the Renewables and storage pathway, the rate of decline is more gradual, due to the lack of long duration flexible capacity necessary to completely eliminate the need for legacy inflexible power plants.
Both pathways rely heavily on the addition of renewables, but the overbuild of renewables can also result in curtailment. Excessive curtailment, which can indicate system constraints and result in wasted energy, can be a significant issue.
In the Renewables and storage pathway, curtailment rises sharply, reaching 55% by 2050, compared to only 5% in the Balanced pathway. The cumulative curtailed energy in the Renewables and storage pathway from 2025 to 2050 could meet the entire 2023 global power demand for over 15 years.
In the Renewables and storage pathway, the land needed for wind and solar infrastructure alone would cover an area comparable to the size of continental Europe, over 10 million km².
By adding a small amount of balancing power plants in the Balanced pathway, we can halve the total required renewable capacity and the land needed to build wind and solar infrastructure.
In evaluating the different pathways to achieve net zero, the modelling results are compelling: the inclusion of balancing power plants is crucial for cost-effective system optimisation. Renewable energy sits at the core of decarbonisation, but system reliability hinges on flexibility.
Flexibility comes in various forms, each playing a vital role. Energy storage is essential for near-instantaneous flexibility and short-duration energy shifting, while balancing power, available during extended breaks in renewable generation, provides flexibility over sustained periods.
Ultimately, deploying balancing power alongside energy storage is the optimal technology mix to support renewables.
With the optimal pathway clear, decisive actions from the entire power sector are crucial to achieve a low-cost and low-emission energy transition in line with the 2050 Paris Agreement. Instead of only focusing on the acceleration of renewable build up, a holistic system-level thinking must be in place when investing in and planning power systems.
Anders Lindberg, President, Wärtsilä Energy and EVP, Wärtsilä Corporation, shares Wärtsilä's 5 steps towards net zero energy.
Malin Östman, Vice President, Strategy and Business Development, discusses the crucial role of the power sector in cutting emissions.
Michael Ball, Director, Business Development, explains what curtailment is and how it can affect the energy transition.
Our new global power system analysis evaluates the viability and optimality of two widely discussed decarbonisation pathways.
Wärtsilä helps its customers to accelerate their decarbonisation journeys through market-leading technologies and power system expertise.
Using PLEXOS® software, Wärtsilä has completed more than 200 country and power system analyses globally, identifying the optimal power system designs to support the integration of renewables and reduce system operational costs and emissions.
