Distributed energy resource (DER) projects provide an exciting emerging opportunity for drinking water and wastewater utilities. DER energy sources available to utilities can include biogas, hydropower, thermal heat, gas to electricity, solar, and wind. Drawing on all these forms of energy the water sector can potentially generate far more energy than their systems require.

Increasing energy demand for water systems, increasing energy costs, advancement towards green energy and greenhouse gas emissions mitigation goals, and the impacts of climate change are all driving DER. Self-generation of energy may reduce costs, improve system resilience and reliability, and reduce emissions.

As utilities can store energy (e.g., as gas or water at elevation), and can often shift their own energy demands through time, they are an important potential element of a more renewables-based future energy grid. However, DER implementation challenges can be significant and overall costs versus benefits depend on site-specific factors, technology, policies, and regulations.