Biomass.

It’s a word we may be hearing more in Mississippi because it’s the only renewable energy source to score an “A” in an assessment by a private group mapping the state’s energy future.

Flip a switch in any home in the state and the juice may come from any number of sources — hydro or coal-, natural gas-, oil- or nuclear-fired generating plants — or a blend of two or more.

In the years to come, the grid of commercial suppliers may have more sources — and some of us will supply all or part of the energy we consume.

Charlie Mitchell is executive editor of The Vicksburg Post. Write to him at Box 821668, Vicksburg, MS 39182, or e-mail.

The recipe for electricity is pretty simple. The only trick is to make a generator spin. That can be accomplished lots of ways. One is to place a wheel of some sort in a stream of flowing water and let the water spin the generator. More common in Mississippi is to use a fossil fuel as a heat source — coal, natural gas or oil — or use a controlled nuclear reaction to boil water into steam and use the resulting expanding vapor to do the spinning.

Biomass is a different fuel.

It can be wood chips, wood pellets, crop waste or even gas-generating animal waste.

Biomass differs from other fuels because the supply can be replenished and, as we all know, that’s not true for coal, natural gas, oil or even nuclear materials.

Advance Mississippi is a nonprofit coalition of community, business and academic leaders that wants to make Mississippians “energy-aware,” and, perhaps more importantly, guide planning and government policies to help residents and the economy. A reliable energy supply at a reasonable price is, quite simply, essential to keeping and adding jobs in the state.

The group formed last spring and is led by Glenn McCullough, who served as mayor of Tupelo and, perhaps more significantly, chairman of the Tennessee Valley Authority, the nation’s largest public power provider, from 2001 until 2005.

Advance Mississippi scored Mississippi’s potential under the five categories identified as renewable energy sources in the House-passed American Clean Energy and Security Act. After the “A” for biomass, geothermal and hydropower each came in with a “B.” Solar and wind each got a “D.”

In its report, leadership in biomass research at Mississippi State University formed a substantial part of the score. So did an existing wood pellet plant in Stone County, which already sells its product for fuel and the fact that three facilities in the state — in Columbus, Monticello and Richton — already burn biomass fuel to generate heat and make electricity.

Liquid products for vehicles are part of the biomass picture and the report cited biodiesel plants in Natchez and Greenville and the Bunge-Ergon ethanol plant in Vicksburg.

A third form of biomass is collecting methane as a byproduct of waste. The state doesn’t have any sites capturing the gas and using it to fire boilers and make electricity, but Advance Mississippi has identified 12 potential sites.

Geothermal energy in Mississippi wouldn’t involve harnessing the heat of volcanoes, as it does in Hawaii. Instead, new construction would have underground piping through which fluid would be circulated. The ground temperature is constant, so with a transfer mechanism in place, the workload of conventional heating and cooling systems could be reduced.

Pending are proposals by three companies to put turbines in the Mississippi River for hydropower.

Solar and wind mechanisms scored low because, while Mississippi has sunshine and wind, the supply is not as abundant as elsewhere.

Especially in the field of energy, start-up costs, operating costs, output capacity and reliability matter a great deal. None of the technologies can come close to the wattage put out by Grand Gulf Nuclear Station, so what Advance Mississippi foresees is a greater mix. A small Delta town might get all its juice from the river. A small town in the Piney Woods might get power from burning pellets made from compressed bark and sawdust. Systems for larger communities will be more complex and interconnected. A big factor — perhaps the biggest — is how for-profit utilities will change, adapt and figure into the picture.

Some changes will come sooner than others, but the supply of fossil fuels began getting smaller when the first coal was burned in ancient times and has done nothing but grow smaller since the internal combustion engine was fired up in 1889.

It’s reassuring to know that groups such as Advance Mississippi are out there, working with state scholars and thinking long-range. The “winners” in years to come will be those who start the incremental changes first — who don’t wait until tomorrow to do what can be done today.