The US Environmental Protection Agency (EPA) has named the top 20 partners in its Green Power Partnership that are generating their own renewable energy on-site. Combined, the top 20 partners are generating more than 736 GWh of renewable energy on-site each year.

Leading the list are Kimberly-Clark Corporation, the Los Angeles County Sanitation Districts, the City of San Diego, the San Jose/Santa Clara Water Pollution Control Plant, and CalPortland, a cement company.

Like many paper companies, Kimberly-Clark produces electricity from biomass waste generated by the pulp manufacturing process. Cities and sanitation districts tend to generate methane at their wastewater treatment plants and can convert that methane to energy, accounting for much of the green power generated by the California cities of Los Angeles, San Diego, and San Jose, while CalPortland has its own wind power facility.

The top 20 partners also draw on other biomass energy sources, solar power, and small hydropower to meet their energy needs.