The numbers are in and the verdict is out: Much of the money that governments spend subsidizing solar energy is wasted.

So argues author and Copenhagen Consensus Center director Dr. Bjorn Lomborg in the pages of The Wall Street Journal earlier this week. He points out that Spain, for example, spent more money subsidizing its conversion to solar power than the country spent on its entire system of higher education last year, and that here in the U.S, we spent $14 billion subsidizing renewable energies in 2010 -- $16.5 billion if you count nuclear energy. That was more than four times the $4 billion spent on tax breaks for the entire, more energy-rich, fossil-fuels industry.

All of which may be true, but we're not talking about wasted tax dollars, today. Today, we're talking about waste, period.

Cash from trash

Specifically, we're talking about Waste Management (NYSE:WM), America's biggest trash hauler by revenues -- and apparently, nearly as big an energy producer as the nation's entire solar industry.

Through a variety of alternative energy projects, from burning trash in incinerators to generate electricity ("waste-to-energy"), to capturing waste "landfill gases" for refinement into clean natural gas, Waste Management generates the energy equivalent of 9.8 gigawatts, or GW, of electricity. In contrast, every solar energy company in the nation -- combined -- generates only a little more than 10 GW. One area of particular growth at Waste Management is the use of landfill gases to power trucks that run on compressed natural gas.

Today, Waste Management has the ability to produce the equivalent of 680 megawatts worth of electricity from methane and other gases produced at its dump sites. That's enough energy to power nearly half a million U.S. homes annually.

And as big as Waste Management is already, it aims to get even bigger.

Last month, Waste Management announced a plan to build a plant in Fairmont City, Ill., that will convert gases generated by its Milam Landfill into pipeline-ready natural gas that can power compressed natural-gas-fueled trucks. Waste Management estimates that this single landfill will produce enough gas daily to run 400 large CNG-fueled trucks. The project is expected to be up and running by late summer 2014.

Once it is running, it will be the third such plant that Waste Management operates for this purpose. And even those represent just a small fraction of the 130-plus projects the company has in operation around the country, using landfill gas to produce natural gas fuel, or burning gas on-site to produce electricity. Over time, the company aims to keep adding projects until, by the year 2020, it's generating enough renewable energy to power more than two million U.S. homes -- up from 1.2 million currently.

Nearly as big as solar

Let's put those numbers in context. If Waste Management succeeds in its goal, we're talking about 67% total growth in energy production over the next seven years ... for a company that's not even, strictly speaking, in the energy production business.

In contrast, thin film solar energy company First Solar (NASDAQ:FSLR) does about $3.5 billion in annual revenue today, and analysts think it may grow its business to $4.2 billion annually by 2016 (as far out as projections are available). That's only 20% growth in three years -- versus Waste Management's projection of more than three times as much growth, in only about twice as many years.

Now, are their other energy production companies that are growing their businesses faster than Waste Management? Sure there are. Analyst estimates for revenue at SunPower Corporation (NASDAQ:SPWR), for example, call for 52% growth between now and 2016. Elon Musk's much smaller SolarCity (NASDAQ:SCTY) venture for leasing rooftop solar systems is growing even faster -- tripling its revenues between now and 2016, if analyst estimates are to be believed.

Foolish takeaway

Numbers like these show that Waste Management is growing this tangential part of its waste-removal business at a respectable pace -- slower than many pure-play alternative energy companies, to be sure, but faster than others. That Waste Management is able to do even this much when it's not even technically the company's job to try and solve the world's energy problems is nothing short of remarkable.

Not to be outdone, these 3 traditional energy companies are booming

