Kris de Decker
The Flamish energy thinker Kris De Decker blogs at “Low Tech Magazine“, was guest author at “The Oil Drum” and writes for many prominent newspapers in Belgium, the Netherlands and the UK. De Decker presents a big picture view on the possibility of a 100% renewable energy society. De Decker preaches “low tech” if not “no tech”.
The author admits that there is potentially more than enough renewable energy available. In Europe 10 times, in the US even 100 times present day electricity consumption, that’s not the problem. The real issue is intermittency. How can we guarantee that our energy grids remain stable, like they have been over the past hundred year, when we switch from fossil fuel to renewable energy? They author describes the intermittency of wind and solar in more detail and we assume he has done his homework. A first positive observation is that throughout the year solar and wind intermittency somewhat compensate each other. There is more wind in the winter months and more solar in the summer.
De Decker lists five strategies to combat the negative consequences of intermittency:
- 1. Backup Power Plants. Don’t opt for 100% renewable energy supply but keep fossil fuel backup capacity alive. And since it regularly happens that no renewable energy is available at all, this would imply that all fossil fuel power generating capacity must remain in place. The only difference is with the present is that they will be (partially) idle for a long time. Essentially a hybrid system.
- 2. Oversizing Renewable Power Production. “Solution”: build so much capacity that supply always matches demand. The author admits that this would lower the energy efficiency (EROI) because the energy system would over supply which necessitates switching power generation off.
- 3. Supergrids. Another more practical way to combat intermittency is connecting large geographical areas into a single supergrid and use “statistics” to even out irregular supply. This would require a continental grid with much higher voltages and in Europe a renewed grid with twelve times more transport capacity.
- 4. Energy Storage. The author claims that in the case of Europe, 400 TWh net storage capacity is needed or 1.5 months worth of consumption. Pumped hydro can supply 80 TWh and car batteries 7.5 TWh. The rest should be batteries.
- 5. Adjusting Demand to Supply. The author (correctly) questions the necessity of “supply should always meet demand”. Why not consume energy if it is available. The Dutch of the 17th century for instance reclaimed new land by pumping it dry and sawed planks for their commercial fleet with wind power, despite its intermittency.
There is not much wrong with the article and De Decker basically supports the idea of a 100% renewable society even if he is skeptical that we can have a plug-and-play solution and instead advocates that we should learn to live with a less comfortable situation where demand will follow supply instead of the other way around.
Is he right? Eh no. He is ignoring the impact of other promising storage technologies. Take the blueprint of the 100%-renewable energy model as promoted by the renowned German Fraunhofer Institute. Note this is the overall energy picture, not just electricity. The model and numbers are for Germany, but can be scaled up for Europe, with adaptions in the numbers for the respective local situations:
[source] 100% renewable energy blueprint for Germany according to the Fraunhofer Institute
Summary in numbers:
Input: 542 GW intermittent renewable energy, mostly wind (200 GW) and solar (252 GW).
Storage: batteries 52 GWh, pumped hydro 60 GWh, power-to-gas (methane) 88 GW and other, see legenda:
Gud – “Gas und Dampf” (gas and steam).
KWK – “Kraftwärmekopplung” (co-generation. “power-heat-coupling”)
Solarthermie – thermal solar (solar collectors)
BHKW – “Blockheizkraftwerke” (co-generation. “block heat and power generation”)
Gas-Wärmepumpen – Gas-heatpumps
Pumpspeicher – Pumped storage (hydro)
Wärmespeicher – heat storage (water medium)
Wärmelast – heat load
WP – “Wärmepump” (heat pump)
Überschuss Wärme – Excess heat
Essential is the Energiesanierung (energy renovation) of buildings, which should result in a reduction of space heating energy requirement of 64.9% as compared to 2010 level.
According to the Fraunhofer Institute would the cost of this renewable energy system not be higher than our current fossil fuel based energy system.
[lowtechmagazine.com] – How (Not) to Run a Modern Society on Solar and Wind Power Alone
[krisdedecker.org] – Kris de Decker
[fraunhofer.de] – 100 % Erneuerbare Energien fuer Strom und Waerme in Deutschland
[sueddeutsche.de] – Wie Deutschland auf 100 Prozent Ökostrom umsteigen kann
[acatech.de] – Stabilität im Zeitalter der erneuerbaren Energien