When people think about going solar, they’re usually thinking about their pocketbooks, not the planet. That’s reasonable, of course, since homeowners save an average of $84 a month with solar.
And when people do think about saving the planet with their solar panels, they’re probably thinking more often about the incredible amounts of carbon pollution they’ll be avoiding by switching to clean energy.
But a lesser-known fact about solar is that it also saves lots of water, and on World Water Day — and one that’s happening in the midst of a devastating drought in the West — that’s an important fact to highlight.
The infographic below shows how our four of the most-common energy sources use water at every stage. In a nutshell, solar wins across the board.
Storage and Disposal
Coal: A typical 500-MW coal-fired power plant will create close to 200,000 tons of sludge waste per year, according to the Union of Concerned Scientists, as well as 125,000 tons of coal ash. This waste leaps into the headlines when it spills into waterways, destroying rivers and polluting drinking water, as it has at large scale in Tennessee and North Carolina in recent years.
Natural Gas: The post-generation water impacts of natural gas are negligible, although the EPA notes that “pollutants and heat build up in the water used in natural gas boilers and … is often discharged into lakes or rivers.”
Nuclear: There are no hard data, but one estimate — which may be on the low end — puts nuclear waste disposal’s water use at 3 gallons per MWh of energy generated.
Rooftop Solar: Another instance where hard data don’t exist, especially not on a per-MWh basis, but several studies have shown that both solar panel manufacturing and disposal can create toxic waste that affect water supplies, such as when lead or cadmium seep into groundwater when end-of-life panels are sent to landfills. However, the Silicon Valley Toxics Coalition, which has studied these issues extensively [PDF], notes that those wastes can be reduced and avoided through responsible recycling practices, and that state and federal laws govern proper disposal of solar panels.
When you look at it this way, taking into account the water impacts of our energy choices, not only do the hidden costs become much clearer, but it also underlines how much more of a benefit solar brings to the world.
So this World Water Day, go solar — for your pocketbook and for the planet!