Balancing GHG mitigation and land-use conflicts: Alternative Northern European energy system scenarios.

• Near-optimal low-carbon energy systems with the least spatial conflict are modeled. • Required land for energy infrastructure is quadruple in 2040 at the cost optimum. • Raising 10% costs from the optimum reduces 58% required land area. • Costs of averted land per unit are high compared to land market prices. • Role of nuclear power in lowering area impact depends on flexibility from hydrogen. Long-term power market outlooks suggest a rapid increase in renewable energy deployment as a main solution to greenhouse gas mitigation in the Northern European energy system. However, the consequential area requirement is a non-techno-economic aspect that currently is omitted by many energy system optimization models. This study applies modeling to generate alternatives (MGA) technique to the Balmorel energy system model to address spatial conflicts related to increased renewable energy deployment. The approach searches for alternative solutions that minimize land-use conflicts while meeting the low-carbon target, by allowing a 1% to 15% increase in system costs compared to the least-cost solution. Two alternative objectives are defined to reflect various aspects of spatial impact. The results show that the least-cost solution requires 1.2%–3.6% of the land in the modeled countries in 2040 for onshore wind and solar PV installations. A 10% increase in costs can reduce the required land area by 58% by relying more on offshore wind. Nuclear energy may also be an option if both onshore and offshore areas are to be reduced, or in a less flexible system. Both offshore wind and nuclear energy technologies are associated with higher risks and pose uncertainties in terms of reaching the climate targets in time. The changes in costs and required land areas imply significantly higher annual costs ranging from 200 to 750 kEUR/km2 to avoid land use for energy infrastructure. Overall, this study confirms that the energy transition strategies prioritizing land savings from energy infrastructure are feasible, but high risks and costs of averted land are involved. [ABSTRACT FROM AUTHOR]