New Processes Electrifying Ideas — Chemicals Produced on Surplus Energy
Could “surplus” electricity be put to work in flexible chemicals production capacities that are switched on and off according to energy availability?
As the share of renewable energy grows, the volatility of the energy supply increases as well. Germany with its “Energiewende” (energy turnaround) is at the vanguard of this challenge, but other countries globally are pushing forward the installation of solar parks or wind power plants, and they will face the same issues. In the past, storage technologies have been in the focus, and they are still being developed at high pace. But recently, some other ideas have been put forward that address the demand side of the energy equation.
The chemical industry has a number of processes that can be driven either by electricity or by other means; therefore, it seems predestined to play an important role in “demand-side management”. Electrolysis ranks high among them; for example, the capacity for chlor-alkali-electrolysis in Germany alone is five million tons per year, corresponding to a connected wattage of 1,450 MW, and is already partly used to level peaks in electricity generation.
Compared to batteries or physical storage, there is an efficiency gain if the electrolysis is performed at low current density, and the chemical product has a higher energy density. But as for all large chemical plants, the primary goal is to maximize capacity utilization. If plants are made more flexible, however, they have to be dimensioned above their average sales volume, and interim storage has to be installed. Due to the current small prize spread on the energy market, this is usually not economically viable if there is no additional compensation. The same is true for the flexibilization of most continuous processes.
Usually batch processes offer more flexibility as the starting point can be chosen without changing other process parameters. This applies universally and is not restricted to electrochemical processes as electricity is used for heating and cooling, compacting and pumping as well.
The generation of steam (power-to-heat) is also an option that can be relatively easily implemented and is in use at a couple of locations in Germany.
In addition to existing plants and processes, a number of other options are currently discussed. Read more on the next page ...