Eco-power to the max

Many Europeans (in particular those living north of the Alps) spent the most recent Easter weekend outdoors: riding mountain bikes, leaping into lakes or taking day trips to the coast. Temperature high ‘Katharina’ was welcomed with glee by those who had opted to stay at home as they were able to enjoy the glorious sunshine accompanied by a nice cool breeze. But there was another way in which the weather helped the continent to recharge: In Germany, for example, on Easter Monday, according to calculations by the utility E.ON, enough power was generated from renewables that it was theoretically possible to cover the nation’s entire electricity demand from renewable sources between 11am and 4pm. According to the company, the maximum electricity load of 49.5 gigawatt hours (GWh) was offset by up to 52 GWh generated from green sources.

Guido Hommelsheim, who together with his colleagues controls RWE’s power plant fleet from the trading floor of RWE Supply & Trading, has taken a closer look at the figures for Germany. “On Easter Monday at 12.45pm for example, it would not have been possible to meet demand without the additional help of conventional power stations, despite the weather conditions”, says Hommelsheim. Even though solar contributed 33 GW, wind supplied around 15 GW and biomass and hydropower added 5 GW and 3 GW respectively, lignite (4.2 GW), hard coal (1.6 GW), nuclear (3.6 GW) and gas (1.4 GW) still played their part in generating the energy mix.

Overall, the trend continued on into Easter Tuesday albeit with one considerable difference. Although renewables once again took on the lion’s share of power production, as it was a normal working day (albeit during the school holidays) consumption was notably higher, meaning conventional power plants were also needed.

Things were much the same in Great Britain, where demand was lower due to the bank holiday and the lovely weather ensured power generation from solar power systems was high. According to UK grid operater National Grid, it was not necessary to source electricity from coal-fired power stations for a period of more than 90 hours over the course of the bank holiday weekend. The fact that the island was able to completely do without coal-based power for so long was unprecedented. The previous record had been 76 hours and 10 minutes in April of the previous year. For reasons of climate protection the British government is planning on decommissioning all coal-fired plants by 2025. For now, the raw material still contributes just shy of 10 percent to national power supply.

Negative spot market prices

The good weather made for a change of pace on the electricity market; in particular on the spot market, the exchange for trading last-minute electricity reserves, where traders watched prices drop below zero. This always happens when more power is generated than can be consumed. Simply put: those purchasing energy at these times are in fact paid for the privilege. At times in the afternoon on Easter Monday, the price fell to between – 83 and – 155 euros per megawatt hour. However, it is important to note that this negative price did not apply to all electricity produced but only to the portion traded on the intraday spot market.

Market observers point to another possible reason for the significant price fluctuations, in addition to the exceptionally good weather: Apparently, before heading off into the long weekend on Holy Thursday, some power producers failed to adapt their resource planning ahead of the Easter bank holidays. “RWE’s power dispatch centre on the trading floor is manned around the clock and also implements the necessary pre-planning processes”, stresses Hommelsheim. “That’s why we’ve stayed within our expected margins in terms of power plant usage and market prices.”

Although negative prices turn things upside down, they are not necessarily damaging. “Rather, they are a sign or rather an incentive for our entire power system becoming even more flexible as a result of the energy transition”, is the Federal Ministry of Economics and Technology’s take on the matter. “Through producers and consumers reacting to power fluctuations from renewables; through reinforcing the coupling of the German power grid and markets with those of its neighbouring countries; through storing surplus power and using it at a later date.”

Gerben Hieminga, Energy Specialist at Dutch bank ING agrees entirely: “Negative prices can help expedite the development of more energy storage facilities. Imagine a fully functional storage system had been in place this weekend just past. It would have undoubtedly served as a buffer.”