Hopefully, you will not pass over this letter because you are fed up or bored with the innumerable words that have already been written about the global climate conference in Paris. The world’s leaders have voiced their concerns and talked about the real need for reductions in greenhouse gas emissions. Leading magazines have dedicated many pages to the issue. You might have read about a possible carbon tax, about a cap-and-trade mechanism to go for the most economic reduction measures, and maybe about a carbon-added tax to replace VAT. Greenpeace has stated that a price of some €80 per tonne of CO2 is needed before serious reductions will take place. Yet no real information was given about the technical and economic challenges involved.

In 2015, almost 35 billion tonnes of CO2 were emitted into the atmosphere. When Maria van der Hoeven retired this summer as the boss of the International Energy Agency, she said that if global emissions continue at this level, the point of no return will be reached between 2035 and 2040. However, if the trend in fossil fuel use of the past decades continues, the world will emit some 70 billion tonnes of greenhouse gases in the year 2040. Therefore, unimaginably large steps are needed for reductions. To increase the current, meagre 1.5% of energy supply from such resources as wind turbines and solar panels to a significant level, not only the connected capital investments are a factor. It is especially the intermittency of these resources that creates a challenge.

Accommodating a small fraction of energy supply from wind and solar radiation poses no problems. The challenges rise exponentially, however, with increasing proportions of such renewables. The best wind turbines have a capacity factor of 30%. If one wants to generate 60% of electricity demand with such wind turbines, one has to install a wind-power portfolio of 200% of the average demand. That means that the output of these wind turbines often exceeds demand by more than a factor of two if no curtailment is applied. Such output peaks would disturb the whole power network. Moreover, there will always be prolonged timespans without any wind. Solar panels in moderate climates are much worse, since they have a capacity factor of only 10% and never produce anything during the night. And electricity is responsible for only 15% to 20% of final energy use in the developed world.

Just waiting for solutions that will entirely exclude the use of fossil fuels in supplying the world with energy is the worst possible decision. Huge steps can already be made by integrating heat and electricity use with distributed cogeneration systems in combination with heat pumps. You will find an article in this magazine about a sophisticated low-cost approach in Hamburg, Germany. The local utility uses a combination of multiple cogeneration units as a virtual power plant that provides unsurpassable reliability and flexibility for backing up renewables. German policymakers are convinced that such cogeneration units, in combination with renewables, are the preferred solution to reduce fossil energy use and combat greenhouse gas emissions. As a result, an additional 10 GW of agile cogeneration capacity must be installed in Germany before the year 2020. That is super-good news for the Decentralized Energy sector. Many other countries should follow this example from Germany.

Hopefully, at least some of the 20,000 people involved in the Paris meeting mentioned our already-available, practical and economical solution. Unfortunately, Decentralized Energy was not invited to give a keynote speech in Paris. It would therefore be great if you, our readers and stakeholders, could help in actively spreading the good news about our realistic solution.

Dr Jacob Klimstra, Managing Editor www.decentralized-energy.com