Oil and water don't mix, but maybe oil and solar power do. A marriage between the two at Chevron well in Coalinga, just down the road from my office in Fresno, started me thinking about other possible energy partnerships.

My colleague, Mike Nemeth, explored the potential relationship between solar and fuel cells in this post and here - especially how they could work in decentralizing energy.

The city of Tulare, which is about 45 minutes from Fresno, has established a showcase partnership to slash costs at the energy-hogging wastewater treatment plant. The combo includes methane digester gas, fuel cells, solar power and, soon, a 1.2 megawatt, 6-hour battery. The battery will store part of the solar energy during the day and discharge it at night for peak shaving, says Public Works Director Lew Nelson.

Nelson said he's not aware of any similar combination in use at a water treatment facility.

But there are other types of energy partnerships. For example, a Walmart distribution center in Canada opened in 2010 with wind turbines and solar panels on its roof, and vehicles powered by hydrogen fuel cells. Read more here and here.

The possibilities are almost endless. Steve Leone of RenewableEnergyWorld has some ideas Here . I'm especially intrigued by the prospects of combing solar and geothermal: a true marriage of heaven and earth.

Photo of City of Tulare fuel cell project