Denis Bonnelle

Biography

Denis Bonnelle is a physicist (former teacher in maths speciale and technical high schools) and economist (enarque). Over the past 20 years, he has written several books, in French and English, on climate change and renewable energies. His current research focuses on the conditions under which solar and wind power can make a major contribution to climate change in just a few decades, without destabilizing the economy. In his view, this means scaling them up, taking seriously objections to their intermittency and to the stability of electricity grids if their market share were to become dominant, and developing the use of electricity in other sectors, all with a highly industrial approach. He was a member of a National Research Agency working group on geoengineering, and is treasurer of the Observ’ER association, which publishes the magazines Le journal du photovoltaïque, Le journal de l’éolien and Le journal des énergies renouvelables.

Conference: Will the climate emergency be over by 2050?

As far back as 1896, Svante Arrhenius calculated that unrestricted exploitation of fossil fuels could warm the climate by 5° C. As the New York Times recently reminded us, in the 1980s, key decision-makers came very close to seriously tackling climate change. And now we need to completely change our energy system, among other things, before 2050. The solutions are there: photovoltaics, wind power, etc., are perfectly mature technologies. And their economics are very favorable when financed over the long term and at low interest rates, i.e. when we think in terms of a long time horizon, which is relevant when we are motivated by the fate of future generations. What remains to be done is to manage their variability over time, i.e. to make progress on electricity storage, whether for daily, inter-seasonal or intermediate regulation… The most suitable solution uses lakes or dams at altitude, which are filled from below by pumping. This is different from conventional hydropower, so it’s not true to say that all the potential is already 100% exploited. But working on this issue in the form of backward planning is undoubtedly the greatest urgency today.