Storage Remains the Missing Link for Renewables

The 800 pound gorilla of grid scale energy storage is closed loop, off river, paired lagoon pumped storage hydroelectric systems.

Round trip energy efficiency is about 75 per cent (with a 2-5 per cent further energy penalty if the system is charged exclusively from well water). Minimum delta H is 30 meters, which, BTW, exists at at least 30 per cent of wind energy sites west of Mississippi River and with lagoons no more than 1 km apart.

Lagoon systems for water storage (mostly ag) and water treatment are a well established technology. Civil costs with local on-site non-rock soils and water retention/erosion control features of the berms runs about $10 per cubic meter of berm. For example, at wind farms in the range of 100 to 200 MW nameplate, the civil, plumbing and electrical costs plugged into the wind farm grid for the same average MWhr 24 hour day (40 per cent name plate) runs about one-half of the cost of the tower and machine portion of the wind farm.

If you have such a wind farm, let's do it.

Water is a much more precious commodity in these parts to allow its use in pumped hydro. Sorry. NIMBY. Actual advance announced just last week on the new Aluminum-graphite battery system looks like a winner - cheap materials, easy fabrication, low to no fire danger, and 1000's of recharge deep cycles, with 2-3 minute re-charge times. It is like nothing I have ever seen before this point.

Although for large projects, thermal storage is at least as good as pumped hydro, requires no elevation relief or water resource committment.

www.isentropic.uk

This company is in the business of storing renewables as heat using a compressed air heat transfer system that is unique in the industry.

For a lagoon system, in most of the High Plains the net (counting precipitation) annual evaporation is less than 1 meter. Other losses of water are recharge to the aquifer from which the water (other than surface water) may be drawn. Proper sealing reduces the recharge to the aquifer to about the same as the annual evaporation loss. Otherwise, closed loop pumped hydro is recycle - no down stream discharges.

When batteries are at 1 gm per watt of the AL-C variety for grid apps, they will begin approaching the value of pumped hydro. Want the full scope on pumped hydro, try the AHA conference in DC later this month.

Do your numbers.

I think you are being somewhat blunt about this, and a bit insulting. Heat storage is already on a par (as to efficiency) with pump hydro. I think the new Aluminum batteries will outstrip both, eventually even on capacity.

Pumped hydro is probably capable of far more capacity than either in areas with good relief, ample water availability, and lots of extra installed conventional or renewable power available to the grid.

I loath, I repeat loath the idea of pumping precious, valuable ground water (needed for city utilities, agriculture far more than electric power storage I especially hate the idea of injecting water from some fetid storage pond back into the aquifer, and it reeks of the sort of idea a total clown would think of. Would you like me to go further? You can tell that to your whole stupid conference, and then put it where sunlight is never incident.