As the anniversary of Sir David MacKay’s untimely death approaches, I think we should honour his memory by trying to update Sustainable Energy as a crowd-sourced project. I have made an initial attempt to suggest how we might develop the section on photovoltaics but others will want to suggest other rewritings to reflect today’s extraordinary pace of change in solar and other energy sources. We need Sustainable Energy as much as we ever did and we want it to be as up-to-date as possible.

This hugely influential book was published eight years ago and it still sells well today. It had been in preparation for several years. Sustainable Energy – without the hot air represents the best possible summary of what David could find out at the time. But things change and I believe we best celebrate his memory by trying to keep his work as up-to-date as possible. In the PDF attached to this page I have written some suggestions for how the 800 words that David wrote on photovoltaics might be amended to reflect changes after the book was written.

Since 2008, the fastest developments have been in solar power and in batteries although improvements in offshore and onshore wind have also been remarkably fast. Perhaps the best way of illustrating just how rapidly solar photovoltaics have moved on is to quote the figure that David used (using data from a then-recently opened solar farm in Germany) for the cost of providing each person in the UK with 50 kWh per day. The number was about €91,000 for each inhabitant. Today, that has fallen to about €18,000, or just under 20% of the cost less than a decade ago.

That number is still enormous, but it would provide each of us with about half of all the energy, not just electricity we needed. (Energy use has decreased since David completed his book). Solar photovoltaics increasingly look as though they will become the cheapest way of delivering the energy a modern society needs. This is true for the UK and doubly so for the nearly 50% of the world’s population that lives in the tropics.

But to rely on solar means we will also need to find ways of storing energy economically. Understandably, David’s book does not contain much on this most vital of modern energy concerns. Although, for example, he mentions lithium batteries, he could have no knowledge of how Elon Musk and others have pushed the cost down by a least as much as the decline in PV prices since 2008. So David’s sections on energy storage and, in addition, his writings on wind and possibly nuclear need also to be updated. And we need to work again on his useful ‘stack’ of potential different contributions to the UK energy need. We will want to include sections on the scope in a modern economy to move energy demand from one period of the day to another, a topic that had barely begun to be considered a decade ago.

Some proposals for updating David MacKay's section on solar photovoltaics

The comments above are only tentative suggestions. But I do think those of us interested in ensuring that energy policy in the UK remains science-based and relies on good, robust numbers should be working together to keep David's unmatched work as an invaluable source.