Even the term HPOWER captures its potency as a waste-management strategy. The plant at Campbell Industrial Park stands as a recycling success story, deriving electricity from waste that otherwise takes up a lot more space in Oahu’s limited landfill space.

But HPOWER isn’t all-powerful, and Honolulu can’t let this technology diminish the drive to refine other solutions.

The facility is run by Covanta Energy, which operates 40 such waste-to-energy plants worldwide. Nationally, 86 plants in 24 states have the capacity to process more than 97,000 tons of municipal solid waste per day, according to the Energy Recovery Council, a national trade group.

According to the council, plants like HPOWER produce carbon emissions but below the rate of coal and even of oil, which powers most electric generators in the state. Waste-to-energy produces 1,294 pounds of carbon dioxide per megawatt hour of power, compared to 2,138 pounds for coal and 1,496 for oil.

So although the plants are expensive propositions for municipalities — no new ones have been built since 1995 — this technology is unequivocally a good bargain for Honolulu. Its particular value: Oahu is a small island with severely limited landfill space.

The reduction of the waste stream becomes a paramount concern, and waste-to-energy has taken a bite out of that challenge. An ash residue still remains, bound for the landfill, but the process does eliminate some 90 percent of the volume burned.

That’s why the city expanded its capacity in 2012. And, say officials for the city Department of Environmental Services, a $10 million project to build a sewage sludge receiving unit at the HPOWER plant will be a further improvement.

The sludge is currently combined with shredded bulky items to make it more manageable at the landfill, officials said; processing it for combustion at the plan means both the sludge and much of the bulky-item waste stream can come out of the landfill.

All of this said, the most cost-effective way to winnow what’s going to the landfill does not lie merely in further expansion of HPOWER.

Curbside recycling has proven to be a net gain for Honolulu, officials said: Although the commodity market is somewhat volatile, the collection of recyclables in the blue bins has yielded more than it costs to run the program, even more than the value of the electricity that waste would have produced in incineration.

There is technology to further reduce what HPOWER leaves behind, but more study needs to be done. Plasma arc gasification — a process converting carbon-based materials in waste products to gas while inorganic materials and minerals yield a rock-like product — is one that, advocates believe, can drastically reduce the need for landfills.

But we’re not there yet. And certainly, the growing neighbor islands will have to contend with this waste-management issue as well. On all the islands, boosting the consumer recycling rate remains an imperative, as well as initiatives that would discourage the excessive use of packaging.

For example, the ordinance to ban the dispensing of shopping bags at many retail centers, due to take effect next year on Oahu, can help to foster habits that discourage excess waste. Stores are already ramping up the availability of reusable totes, and some shoppers are getting used to adapting boxes or simply carrying the items out unbagged.

As much as HPOWER has aided Oahu in its waste-management challenge — all the while producing energy at a lower cost than burning oil — it has not eliminated the need for landfills.

On this island especially, the need to devote another parcel of land to landfill use means the inevitable contentious protest from the neighbors and the loss of more acreage that could have a more productive purpose. We should strive to avoid both those outcomes.