World may have crossed solar power 'tipping point', says study

The world may have crossed a "tipping point" that will inevitably make solar power the main source of energy, suggests new research.

The study, published in the journal Nature Communications, finds that solar photovoltaics (PV) is likely to become the dominant power source before 2050 – even without support from more ambitious climate policies. This is based on a data-driven model of technology and economics.

The study was led by the University of Exeter in the UK and University College London (UCL).

Solar energy is the most widely available energy resource, and its economic attractiveness is improving fast in a cycle of increasing investment, says the study. “We find that, due to technological trajectories set in motion by past policy, a global irreversible solar tipping point may have passed where solar energy gradually comes to dominate global electricity markets, without any further climate policies,” the researchers said.

Uncertainties arise, however, over grid stability in a renewables-dominated power system, the availability of sufficient finance in underdeveloped economies, the capacity of supply chains and political resistance from regions that lose employment. Policies resolving these barriers may be more effective than price instruments – such as a carbon tax – to accelerate the transition to clean energy.

"The recent progress of renewables means that fossil fuel-dominated projections are no longer realistic," said Dr Femke Nijsse, from Exeter's Global Systems Institute.

"In other words, we have avoided the 'business as usual' scenario for the power sector," she said.

"However, older projections often rely on models that see innovation as something happening outside of the economy. In reality, there is a virtuous cycle between technologies being deployed and companies learning to do so more cheaply. When you include this cycle in projections, you can represent the rapid growth of solar in the past decade and into the future. Traditional models also tend to assume the 'end of learning' at some point in the near future – when in fact we are still seeing very rapid innovation in solar technology."

"Using three models that track positive feedbacks, we project that solar PV will dominate the global energy mix by the middle of this century."

However, the researchers warn that solar-dominated electricity systems could become "locked into configurations that are neither resilient nor sustainable, with a reliance on fossil fuel for dispatchable power".

Instead of trying to bring about the solar transition in itself, governments should focus policies on overcoming the four key barriers.

For grid resilience, this means investing in other renewables such as wind, transmission cables linking different regions, extensive electricity storage and policy to manage demand (such as incentives to charge electric cars at non-peak times). Government subsidies and funding for R&D are important in the early stages of creating a resilient grid, she added.

Access to finance is highly concentrated in high-income countries. Even international funding largely favours middle-income countries, leaving lower-income countries –particularly those in Africa – deficient in solar finance despite the enormous investment potential.

A solar-dominated future is likely to be metal and mineral-intensive. Future demand for critical minerals will increase, said the researchers.

As for political opposition, regional economic and industrial development policies can resolve inequity and can mitigate risks posed by resistance from declining industries.

Commenting on the financial barrier, Dr Nadia Ameli from UCL said: "There is a growing belief that, with the dramatic decline in the global average cost of renewables, it will be much easier for the developing world to decarbonise. Our study reveals persistent hurdles, especially considering the challenges these nations face in accessing capital under equitable conditions. Appropriate finance remains imperative to expedite the global decarbonisation agenda," she concluded.