In the fine tradition of mashups that have produced zombie-enhanced classic novels and cutting-edge high school music efforts, a new UCS mini-report is a stimulating amalgamation of two exciting areas of UCS research, pointing to additional bonuses from closing old coal plants. This Earth Day, you can celebrate water savings, too.
Water Dependence Risks for America’s Aging Coal Fleet highlights the economic vulnerabilities of coal plants and the water implications of our electricity choices. The mini-report builds on:
- UCS’s recently released report on the costs of electricity from coal plants. The Ripe for Retirement effort involved crunching the numbers on every coal-powered generator in the U.S., to see how each stacks up against newer, more efficient, and less-polluting sources like natural gas and wind power. It concluded that a third of all U.S. coal generators — more than 350 in more than 30 states, adding up to some 59,000 megawatts — are “old, inefficient, dirty, and no longer economically competitive.”
- UCS’s Energy and Water in a Warming World initiative, and specifically our Freshwater Use by U.S. Power Plants report. That work helped people understand why and how our energy choices make a difference when it comes to their water habits — how much water power plants pull out of lakes, rivers, and aquifers, and in what ways that water use gets us into trouble.
Coal and Water
Water Dependence Risks for America’s Aging Coal Fleet dexterously pulls those two lines of thought together. The new analysis looked at both those ripe-for-retirement generators that hadn’t yet been put out to pasture, and the whole swath of coal units that utilities and other plant owners have already announced that they’re retiring.
And it turns out that many of our country’s coal plants aren’t just old, inefficient, dirty, and expensive. They’re also thirsty. Big time.
UCS found that most of the generators in the “ripe” category have once-through cooling, which involves withdrawing large amounts of water as part of the electricity-making process. While almost all of that water ends up back in a river or lake, that technology fell out of fashion decades ago because of the harmful effects of all that water withdrawal and the much-hotter water that flows back.
Less Coal, More Water
So what would it mean in terms of water use to have all those inefficient generators stop drawing and consuming (evaporating) water? That’s exactly what Water Dependence Risks tells us:
Water savings potential from coal retirements
- If all of the coal generators already announced for retirement were replaced with natural gas combined-cycle generators using more-modern recirculating cooling systems, “annual water withdrawals would drop by 4,166 billion gallons and water consumption by 29 billion gallons.”
- If the ripe-for-retirement generators were dealt with the same way, “annual water withdrawals would drop an additional by 4,164 billion gallons and water consumption by an additional 49 billion gallons.”
- The figures get even better if all those plants were replaced with energy efficiency and renewable energy options that don’t use any water for electricity generation, like wind and solar photovoltaics. Picking that route means possible savings of some 8,400 billion gallons of water withdrawals and 150 billion gallons of water consumption.
All the water figures are for the power plant cooling water pieces, and don’t take into account water elsewhere in the process, like hydraulic fracturing for getting the natural gas. So technology options that avoid those water quantity and quality implications (see that third bullet, above) can look even better.
Water withdrawal and consumption savings by state
And, in terms of the cooling water opportunities, some states could be bigger winners than others:
- Alabama, Maryland, Michigan, and Wisconsin could each save more than 250 billion gallons of water withdrawals a year with the renewables switch-out, and
- Alabama, Florida, Georgia, and Mississippi could each save more than 5 billion gallons annually.
Sense and Sensibility and Coal Plants
Lots of old, inefficient, and uncompetitive coal generators are already shutting down, and that makes sense in a whole lot of ways. So does taking a hard look at other older coal units that aren’t likely to make the grade, economically. The water profiles of many older plants — the fact that they’re water-sucking (even if not brain-sucking) — means that closing them down can also bring real water savings across the country.
Artfully mashing together an analysis of coal economics and an understanding of power plant cooling water gives yet another fine reason for moving toward an energy future that’s cleaner, healthier, and, it turns out, a whole lot better from a water perspective.
This Earth Day, cause for a bit of extra glee.