Renewables won’t drive up cost of electricity from fossil fuel plants

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Renewable energy has achieved a major milestone: in many cases, it's the cheapest source of electrons you can put on the grid. But the intermittency that comes with renewable energy also poses challenges for the grid, as it has to be able to respond to sudden changes in supply. That creates an economic challenge as well, as we may need to provide incentives for other sources of electricity (including storage) to make up for the sudden changes. These costs are the subject of a new paper that finds that in Germany, costs won't be all that bad.

On the most basic level, the variable output of renewables means that existing fossil fuel plants may need to be switched on and off at short notice. This process has a cost, since it isn't like throwing a light switch; it takes time and fuel in order to get the plants up to speed. Earlier studies have shown that there's a cost from the strain on the equipment involved in cycling on and off, but the cost is dwarfed by the money saved on fuel when the plant isn't run.

Still, cycling doesn't only involve fuel savings. There's also some wasted fuel, as the plants can take time to begin effectively producing energy. The simplest way to think of this is in terms of a steam boiler. You need to burn a fair bit of fuel to get the water to boil before you can start generating electricity, and that fuel costs money. How much money? That's precisely what the new study tried to determine.