100% Renewable EU

A 100% renewable energy system enabling the EU to become climate neutral before 2050 is outlined in a Solar Power Europe/LUT report, with nuclear phased out by 2040 in one scenario. The team’s modelling suggests that it is possible for Europe to reach 100% renewables by 2050 in a Moderate scenario, and by 2040 in a Leadership scenario, with nuclear then phased out. The cumulative social, economic and environmental costs of achieving 100% renewable energy by 2050 in the Moderate scenario are put as 6% lower than the cost of ‘inadequate action’ in the less ambitious Laggard scenario, which reaches only 62% renewables by 2050, thus missing both the targets of European climate neutrality and the Paris Agreement.

The report says ‘the 100% renewable energy system is primarily a solar story’, with solar PV reaching a massive 4.7–8.8 TW in 2050, depending on the scenario, supplying at least 48% of power in the Laggard scenario and 63% of power in the Leadership scenario. By 2050, the other power pillar of the energy transition, wind energy, will, depending on the scenario, account for 28–33% of generation shares, and 1.1–1.9 TW of capacity. The report notes that, despite its lower capacity, ‘due to its higher capacity factors, wind energy provides the highest shares of electricity generation up to 2030, however, solar’s versatility and cost-competitiveness will make it the main source of electricity generation from 2030 onwards’.

The 100% renewable transition triggers an over 60% fall in GHG emissions by 2030, and a fall down to zero in 2050-  or even 2040 in the Leadership scenario. In the least ambitious Laggard scenario, Europe reaches only 53% CO2 emission reductions in 2030.

Electrification is seen as vital: ‘A high rate of electrification is essential to achieving a 100% renewable and integrated energy system’. The drive to electrify about 85% in the 100% renewable scenarios ‘enhances sectoral integration, resulting in significant system efficiency gains, thus lowering the cost of the transition’.  Electrolysers for hydrogen production are also seen as a crucial technology for a 100% renewable energy system. From 2030 onwards, renewable hydrogen contributes to the full decarbonisation of the heat & transport sectors, becoming Europe’s second key energy carrier. In the Leadership scenario, by 2040 Europe can even become an exporter of renewable hydrogen’s product, synthetic fuels.

Given this commitment to green hydrogen, it’s a little surprising that batteries are seen as providing ‘the bulk of electricity storage in a 100% renewable energy system’. The report says ‘As the share of solar & wind increases significantly beyond 2030, electricity storage becomes crucial in providing an uninterrupted energy supply, backing up to 24% of European electricity demand. As the most cost-efficient storage technology, batteries will contribute up to 98% of electricity storage’. But it also says that the ‘the high flexibility of electrolysers enables the efficient uptake of variable electricity generation from solar PV & wind energy, which effectively reduces the demand for electricity storage’. That’s fortunate since it’s hard to see how batteries could deal with the sometimes large and long lasting shortfalls in renewable supply.  Power to gas plus hydrogen storage also helps to limit grid power curtailment. Meantime gas & thermal storage is mainly used in the heat sector, and the report says that can also help with balancing variable demand.

As the report says, ‘the level of sector coupling between the power, heat, and transport sectors depends on the adoption of different technologies. The greater the amount of Power-to-X technologies (power to heat, fuel, gas) the higher the degree of sector coupling. The rate of electrification in the heat and transport sectors depends on the adoption of heat pumps with electric heating, and a technological shift from ICE engines to electric powertrains. The adoption rate of synthetic fuels (methane, hydrogen, and FT fuels) is primarily based on electricity & thus on the electrification level’.

There is some flexible grid balancing in the moderate 100% renewables scenario, the Leadership scenario cranks the integrated mix up to the maximum, with more renewables and higher levels of flexibility from 550GW of additional electrolyser capacity for storable H2, methane and transport fuel production, together the with full use of heat pumps, providing over 60% share of heat generation by 2050.  While the report says that final heat demand will grow most compared to the other sectors, by 2050, it thinks that European heat generation capacity will be dominated by heat pumps and direct electric heating solutions. Renewable synthetic fuels (including hydrogen) contribute towards industrial process heat in the later stages of the transition. So not much P2G hydrogen for heating...

Transport is, as always, the hardest nut to crack. The report says that with only 8% share of renewables today, the transport sector has the longest way to go to reach 100% renewables, and in concludes that ‘a 100% renewable transport sector needs significant synthetic fuels for marine & aviation. Direct electrification emerges as the most efficient solution to decarbonise road transport, but the aviation & marine sectors will rely heavily on renewable synthetic fuels (hydrogen, methane & power-to-liquids)’.

Overall then, we are offered an integrated 2050 multi-sector EU energy mix which it is claimed can deliver on cost and climate targets, with about 15% of the generated electricity being traded across the interconnected regions. That means that the bulk of electricity (85%) is generated within the regions where demand originates. So this enables a highly decentralised energy system design, although coupled with an interconnected and cost-optimised European energy system. As a result, curtailed electricity is less than 5% for both the sustainable scenarios with 100% renewable energy.

Can it be done? Although it may overplay the balanceable solar PV potential, the overall renewable resource should be there, but the high reliance on batteries is a little worrying, especially given material resource issues. So more of a role could perhaps be played by hydrogen storage for long-term balancing, although there are also materials resource issues with P2G and fuel cell technology. Clearly there are plenty of issue for the EU to get stuck into if it is to get to net zero carbon by 2050.