It's a long, winding road for the clump of coal that wants to become a bundle of electrons to power your light bulb.
First, it's at the power plant, where most of the energy inside of it gets cooked off as heat to make steam. That turns a generator and the resulting electricity has to zip through miles of transmission wires, transformers and other gadgets, losing some of its power with every transfer.
Part of this puzzle can be solved by an existing technology, one that can make electricity generation twice as efficient: combined heat and power.
Also known as CHP or cogeneration, this technology can snag the waste heat drifting off a burning fossil fuel and turn it into useful energy -- by heating water or making more electricity, for example. It can do the same with waste heat from other sources, such as factories.
And unlike new low-carbon technologies, it's been done around the country for around a century. Major universities in California and Texas, for example, use cogeneration at their on-campus power plants. The steaming grates of New York City connect to an underground piping network that imports waste steam from local sources to heat homes.
Why, then, are advocates still wondering when CHP will get its due as an efficiency solution that, if scaled up, could take a bite out of the nation's carbon footprint?
"We've been around for 100 years, but not that many people know that much about us," Rob Thornton, the president of the International District Energy Association, explained at a Capitol Hill briefing yesterday.
Generating about 85,000 megawatts of power each year, CHP accounts for roughly 8 percent of the country's power. But when $1 billion of CHP funding made it into a draft of the recent appropriations bill, advocates said, Hill staffers lopped it off.
Now, as climate legislation advances on the Hill, CHP backers are making another push.
They're arguing that cogeneration would flatten the demand spikes for electricity that have driven utilities to build extra power plants that sit idle for all but the coldest and hottest times of year.
Slashing Princeton's electricity bills
Advocates call the approach "district heating and cooling." If a power plant is close to where people live and work, a device can capture the plant's wasted heat, channeling it to an underground piping system that ships it to the buildings where people are using their thermostats.
That would get much more power out of the fuels burned in power plants, which currently lose two-thirds or more of the energy in fuel to heat. CHP advocates say the technology can double a plant's efficiency, so that 60 percent of the energy in fuel becomes usable.
It's long proved a useful strategy for some universities, which own many buildings for long periods of time and can therefore reap the cash savings of the up-front investment.
At Princeton University, where the campus's 150 buildings include research labs, professors' offices, sporting complexes and dorms, CHP has helped slash energy use.
In 2005, the campus's peak energy need was 27 megawatts. But a year later, with CHP and a handful of other energy strategies, its peak demand fell to just 2 MW, freeing up the remaining 25 MW for other parts of the grid.
Writ large, advocates say, CHP could dramatically reduce energy needs -- and emissions -- both here and abroad.
Denmark has been the pacesetter, using targeted policies to get more than half of its electricity from CHP. According to a report released by the International Energy Agency yesterday, frigid Finland and Russia check in at roughly 40 percent and 30 percent, respectively.
According to the report, the United States has installed more CHP than any other country. But its enormous energy appetite -- second only to China's -- means this CHP outlay supplies less than 10 percent of its electricity needs.
The report says there is room for scaling up, especially in the United States, China and India. With their massive heating and cooling demand, these countries could pay off the equipment and pipes for CHP quickly. The report projects that the United States could double its CHP levels by 2030, and that China could multiply its levels tenfold.
In the United States, the Energy Independence and Security Act of 2007 authorized $3.75 billion for grants and loans to help communities install the equipment and piping for CHP.
But even with these incentives, the battered economy has made investors skittish about paying the up-front costs for a system that will take years to pay off.
So CHP advocates have turned their attention to a bigger fish: an emissions cap-and-trade bill. The International District Energy Association is asking Congress to allocate extra credits to polluters that use CHP.