This is a copy of the letter from Dr Robert Gross and Dr Phil Heptonstall of the Centre for Environmental Policy and the UK Energy Research Centre printed in the 24 August 2017 issue of The Financial Times. It is a response to Jonathan Ford’s piece from 21 August, The hidden costs of renewable power.

Sir, Hidden costs are not revealed through oversimplification.

The UK Energy Research Centre is not a pro-renewables group, it is a publicly funded, independent academic research consortium. Integrating wind and solar into power grids is a complex topic that requires a focus on credible sources using power system models. Yet Jonathan Ford (“Reforms needed to balance hidden costs of renewable power”, Inside Business, August 21) implies equivalence between our peer-reviewed, systematic review of the engineering and economic literature and an unpublished paper that attempts its own assessments.

The range of cost estimates associated with integrating renewables is wide. It will depend on climatic and demand-side conditions, system size and flexibility — factors largely outside the control of renewables generators, one reason renewables are offered fixed-price contracts in most countries. It may be appropriate to rethink market design for systems with a large amount of renewables. It is important to ensure the system is flexible. But requiring renewable generators to self-balance in the way that Mr Ford suggests would create unnecessary costs and indicates a fundamental lack of understanding of both the physics and the economics of the electricity market.

Energy policy needs to draw on independent and evidence-based analysis that attempts to present the facts clearly and explain where legitimate sources of controversy or uncertainty arise. It would be desirable if reporting on the topic did so too.