A zero-carbon-emissions energy system will rely mostly on low-cost solar electricity, experts say. About 100 giant solar panel factories must be built by 2025 for the world to defossilize its energy supply by 2035.
"We know the world needs to de-fossilize its energy systems," says Christian Breyer, professor of solar economics at LUT University in Lappeenranta, Finland, whose research group models transition pathways to future zero-emissions energy systems. "We need to get to net-zero greenhouse gas emissions — as quickly, safely, and cost-effectively as possible. To do that, we need technologically feasible, cost-optimized transition pathways for every region of the world. Our calculations show how we can do that."
Breyer's cost-optimized model of 2019 shows how a global energy system with net zero carbon emissions can be achieved. In the model, solar photovoltaics (PV) — solar panels — supply 69% of total global primary energy demand for all purposes. The rest comes from wind power, biomass and waste, hydropower, and geothermal power.
His zero-emissions scenario doesn't include nuclear power because it's "simply too expensive," Breyer told DW. "PV technology is becoming cheaper year by year; the construction costs of nuclear power plants, on the other hand, are rising." Moreover, it's much easier, faster, and less risky to install and operate solar power than nuclear power plants.