Flexible Users Will Be Rewarded
Why reverse-osmosis plants suit demand response: seawater is continuous, treated water is storable, and operation needs little labor.
Time-of-day pricing passes some of the cost of peak demand to industrial and residential consumers. Demand response reduces load when electricity is most expensive to generate, and can provide contingency when wind or solar production changes suddenly.
The practical question
The challenge is finding enough energy users suitable for flexible operation. Reverse-osmosis plants have three useful characteristics: they are not labor-intensive, seawater is continuously available, and treated water can be stored.
Most RO plants, however, use very large pumps with a narrow operating range. They demand constant energy at a time when flexibility is increasingly important.
The modular response
Sisyan's proposal was to make the plant's energy demand adjustable by switching independent modules on and off. Water storage would maintain supply while electrical demand changed.
This article is drawn from page 7 of Demand Response Desalination. It describes the paper's 2015 argument rather than a current operating program or market offer.
Calculated from the proposed module
A plant adjustable in approximately 22 kW steps
The paper envisioned plants containing 5-500 independently controlled modules. Every additional module would add or remove about 22 kW of load.