In the seventies of the past century, thinking started about how we use energy. It was the time of the first Oil Crisis and the first Report to the Club of Rome. Now, forty years later, we know a lot more about what energy is used for, and how that develops over time. Nevertheless, our knowledge is still fragmented. We still know little about what we do exactly with all that energy, and even less about how efficient this is.

Street Light Evolution, by Industrial Design students @TUDelft, Photo by Koen Fraijman

An example. We know within a few percent accuracy how much money is invested in renewable energy every year. In contrast, the estimates of how much is invested globally in energy efficiency vary from 130 to 365 billion US$ per year [i]. There is a well-known saying: “what gets measured, gets done”. If you start measuring something, things start moving. The fact that we do not monitor our energy use and our energy efficiency well enough hinders us in effectively managing our energy use.

The pathway that I would like to explore is to substantially increase the use of new data sources that will become available anyway: via smart meters, smart thermostats, building management systems, and eventually via the internet-of-things. If all appliances are connected to the internet in the future, it will be much easier to gather detailed information about energy applications and energy efficiency.

Getting a better understanding of our energy use with help of advanced ICT is just the first – but important – step. The follow-up is that ICT will help us to use energy in a much more efficient way.

Factor 5

Current LED lamps are a thousand times more efficient than candles or traditional oil lamps. Current double glazing transmits only one third of the heat compared to the first generation of double glazing forty years ago. And that was already a factor two better than single glazing. The amount of energy needed for the production of 1 tonne of iron, has been reduced by a factor of 20 in the past two centuries. So, we have already made enormous progress in energy efficiency.

Detailed studies show that there still are enormous possibilities to limit our energy use [ii]. A very successful approach is to set minimum energy performance standards for products. Due to the European CO2 performance standards for passenger cars, new cars in 2021 will only use half the amount of fuel compared to new cars in the beginning of this century. This has also worked well for other energy equipment with limited lifetimes, like household appliances and lamps.

The energy consumption of buildings and industrial installations – which have a much longer life – can also be strongly reduced, but for that large investments are necessary. These investments generally can be earned back, but the initial investments can be a hurdle. Overcoming this can be facilitated with help of adequate financing arrangements.

I would like to formulate a joint challenge. A few years ago, I showed that it is plausible that new products can be made 5% more efficient from year to year [iii]. After three decades this is a factor 5. The technological challenge thus would be: let us work towards improving energy efficiency with a factor of 5 over thirty years.

Health and other benefits of energy efficiency

But is all this hassle necessary? No doubt the answer is yes. The International Energy Agency published a report last year about the multiple benefits of energy efficiency [iv]. I pick three of them.

First of all, there are benefits for health and climate change. It is unimaginable to tackle the climate problem without energy efficiency improvement. But let us also consider other health issues. Transport is an important source of particulate matter, probably the most undervalued environmental issue. Even in Europe particulate matter is an important health threat, but in countries like India and China the situation is a lot worse. Efficient transport – including the transition to electric transport – is an important means to reduce the emissions of fine particles.

A second category of benefits from energy efficiency improvement has an economic character. Higher efficiency makes it possible – given the amount of energy – to produce more light, travel longer distances, in short: do more. That is pleasant for Europe, but of critical importance for countries in development. There, higher economic growth is crucial for good food, good education, good health care and well-being in general.

Third, a seriously undervalued problem is security of energy supply. Lower energy use makes us less dependent on import of energy from risky areas. Energy demand related action can also help with reacting quickly to temporary shortages of energy.


Is this not a sign of technology optimism? Should we aspire to more and more, even if it is with less energy? In 2015, Pope Francis published the encyclical Laudato Si’ [v]. The bishop of Rome provides an extensive overview of the bad shape in which mankind has brought creation. The pope calls on everyone to protect ‘our common home’. The encyclical puts a lot of emphasis on other values than just economic values, like moderation, rest and enjoyment of the good things we have received.

These are indeed important values. Nevertheless, I believe that efficient and renewable technologies also play an important role. As I have shown, there still is a great potential, part of which we already know of, and who knows what else we may discover. Creation is probably a lot richer than we realise today.

Our challenge is – as the Brundtland Commission formulated it in 1987 – a “development that meets the needs of the present generations without compromising the ability of future generations to meet their own needs”. To achieve this, energy efficient technology is an important lever.

This is a summary of my inauguration lecture at Delft University of Technology, held on 16 September 2015. The full recording of the lecture can be found here (in Dutch). Thanks to Willem van Klinken of the Reformatorisch Dagblad who made this summary in the Dutch version.

[i] World Energy Outlook Investment Outlook 2014, International Energy Agency, Paris, France, 2014.

Sizing energy efficiency investment, HSBC/Ecofys, Londen, 2014.

[ii] E.g. K. Blok, P. Hofheinz en J. Kerkhoven: The 2015 Energy Productivity and Economic Prosperity Index, The Lisbon Council, Brussel, 2015.

[iii] K. Blok, Improving Energy Efficiency by Five Percent and More per Year?, Journal of Industrial Ecology, 8(2005)87-99.

[iv] Capturing the Multiple Benefits of Energy Efficiency, International Energy Agency, Parijs, 2014.

[v] Encyclical Letter Laudato Si’ of the Holy Father Francis on Care for Our Common Home, Vatican Press, Rome, 2015.