LA Is Putting Floating Solar and an Iron Battery on a Reservoir

So basically: Los Angeles is gonna float solar panels on a reservoir. LADWP, the city’s power and water department, approved a pilot at Encino Reservoir with a 5 megawatt floating solar array covering about 10 acres of water, plus a 5 megawatt iron flow battery to store the power.

How this got approved

LADWP filed what’s called a Notice of Determination. That’s the paperwork that wraps up the California environmental review. So this isn’t just an idea anymore, it’s cleared to move forward as a pilot.

What’s going in

• 5 MW of floating solar on about 10 acres of the reservoir
• A small 30 kilowatt solar setup on about 4,000 square feet of land next to it
• A 5 MW iron flow battery for long duration storage
• Transformers, inverters and switchgear tied into a power line that’s already there

Hooking into an existing line is a big deal. A lot of solar projects get stuck for years waiting to connect to the grid. This one skips a lot of that.

Why put solar on water

A few reasons it’s actually smart:

• No land needed. Land in LA is crazy expensive. The reservoir is already there.
• Less evaporation. Covering the water with panels means less of it evaporates in the sun. In Southern California water is a big deal.
• Panels run cooler. The water keeps the panels a bit cooler and solar panels work better when they’re not cooking.

Why an iron battery

Most big batteries are lithium. Iron flow batteries are different. They use iron, salt and water, stuff that’s cheap and doesn’t catch fire easily.

They’re bigger and heavier than lithium so you wouldn’t put one in a car. But for something sitting next to a reservoir that just needs to store power for hours and last a long time, they make a lot of sense.

So the idea is soak up sun during the day, store it, and push it out in the evening when everyone gets home and turns everything on.

The catch

It’s a pilot and it’s small. 5 MW is enough for a few thousand homes at best during peak sun. LA uses way more than that. The story didn’t give a cost or a date for when it’ll actually be running.

This is LA testing if it works before going bigger. Which is honestly the right way to do it.

Why it matters

Power demand is going up everywhere. EVs, AI data centers, heat waves with everybody running AC. Cities are gonna need power from every spot they can find.

Reservoirs are basically empty flat space that cities already own. If this works, LA has other reservoirs, and so does pretty much every big city.

Has anyone done this before

Yeah, floating solar is already a thing. China and parts of Asia have huge floating solar farms, and there are some in the US too, mostly on water treatment ponds and smaller reservoirs. A few California water districts have tried it.

What’s different here is LA pairing it with long duration iron batteries right on site, in the middle of a big city. That combo is what makes it a blueprint other cities could copy.

My take

I like this one a lot. It’s not flashy but it’s smart. Use space you already have, save some water, and store the power with a battery that won’t blow up.

It’s small, so don’t expect it to change LA’s power bill. But if the pilot works I’d bet you start seeing panels floating on reservoirs all over the Southwest.