Navitron Renewable Energy and Sustainability Forum

Announcements & News => Media Watch => Topic started by: Stig on September 02, 2019, 02:47:33 PM



Title: Draining Every Hydropower Dam in The US For Solar Panels
Post by: Stig on September 02, 2019, 02:47:33 PM
An interesting, if simplistic, thought experiment:

https://www.sciencealert.com/scientists-are-tantalised-by-the-idea-of-replacing-hydropower-dams-with-solar-panels (https://www.sciencealert.com/scientists-are-tantalised-by-the-idea-of-replacing-hydropower-dams-with-solar-panels)

Seems to miss a couple of important points though:
1.  You'd lose all the energy storage - hydro's big advantage.
2.  You could install floating PV on existing reservoirs anyway.


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: Nickel2 on September 02, 2019, 03:27:45 PM
Ok, how about another one of my 'brilliant' ideas:
Put a solar "raft" on every dam-held lake/reservoir, then use the solar power to back-pump the reservoir when the sun shines.
That way you get to store umpteen megawatt-hours of electricity in the form of pumped hydro, at zero cost to the grid. It then becomes a dedicate storage battery with reduced infrastructure costs.
Don't forget, you heard it here first on the Navitron forum!
PS, I'm only the ideas-man ;D


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: JohnS on September 02, 2019, 04:01:45 PM
Ok, how about another one of my 'brilliant' ideas:
Put a solar "raft" on every dam-held lake/reservoir, then use the solar power to back-pump the reservoir when the sun shines.
That way you get to store umpteen megawatt-hours of electricity in the form of pumped hydro, at zero cost to the grid. It then becomes a dedicate storage battery with reduced infrastructure costs.
Don't forget, you heard it here first on the Navitron forum!
PS, I'm only the ideas-man ;D


But
PV power is produced during the day when demand is higher and pumped storage is recharged at night when prices are low.  Your idea will use high lost opportunity cost electricity to produce surplus electricity when the grid is awash with it.

Will only work for reservoirs feeding hydro plants.  Most reservoirs in England are for water supply storage.

Will only work when there is a lower reservoir to catch the water to be used to back-pump.

Back to the drawing board me thinks.   wackoold


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: M on September 02, 2019, 05:34:21 PM
Ok, how about another one of my 'brilliant' ideas:
Put a solar "raft" on every dam-held lake/reservoir, then use the solar power to back-pump the reservoir when the sun shines.
That way you get to store umpteen megawatt-hours of electricity in the form of pumped hydro, at zero cost to the grid. It then becomes a dedicate storage battery with reduced infrastructure costs.
Don't forget, you heard it here first on the Navitron forum!
PS, I'm only the ideas-man ;D


Sounds good, lots of potential. The downside is there will be times when the PV is pumping and hydro is discharging, but having the PV as a dedicated storage feed is certainly an idea, and it might get a better contracted price for the leccy as it becomes less peaks and troughs, and more flat. I'm sure similar has been touted for wind, where some WT's would actually just be wind pumps, reducing the leccy side costs, and allowing for a smaller number of dedicated turbines from the hydro facility instead, but presumably the wind pumps would have to be close to the reservoir/catchment lagoon. Or perhaps coastal with gravity fed pipes to a central store, from a number of wind pumps?

Back to the PV, the potential would probably be with regard to predictability of supply, and the size of the leccy distribution network - rather than size it for peak PV, it could be sized for a smaller figure, but consistent thanks to the hydro storage.

And of course every size mix in-between, such as say half the PV for distribution, and half for water pumping, with the hydro used to top up generation when needed to provide consistency.


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: Nickel2 on September 02, 2019, 05:36:15 PM
(Modified after post-at-the-same-time by M). Ah yes, think of it this way; A hydro-reservoir need not be full all of the time. If it does not have the reserve to supply night-time electricity as well as day-time, the extra capacity will serve the night customers.
Another way to think of it;  during the day, the grid gets most of it's power from the PV raft, allowing the dam to fill back up from natural resources. The hydro is maintained at synchronous speed, but is not supplying a large current to the grid, so doesn't use a lot of water.
It keeps rotating, and as the sun goes down the PV drops and the load is taken up by the hydro. That way you would not need back-pumping, just good load-management.
Non-hydro schemes, ie irrigation/city use could still supply electricity to the grid/system from their own rafts, further reducing the load on the hydro.
John S - England is not the only country with dams!  ;D


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: pdf27 on September 02, 2019, 08:00:59 PM
Ok, how about another one of my 'brilliant' ideas:
Put a solar "raft" on every dam-held lake/reservoir, then use the solar power to back-pump the reservoir when the sun shines.
That way you get to store umpteen megawatt-hours of electricity in the form of pumped hydro, at zero cost to the grid. It then becomes a dedicate storage battery with reduced infrastructure costs.
Don't forget, you heard it here first on the Navitron forum!
PS, I'm only the ideas-man ;D

It's worth noting that by definition dams tend not to be built anywhere the land is flat. If you want industrial-scale PV systems, you need flat land in practice. So how about filling up the dams with some really cheap self-levelling compound, perhaps a liquid? Makes it much easier to install PV...


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: Nickel2 on September 02, 2019, 08:18:06 PM
Perhaps the PV 'raft' could be made from recycled plastics.


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: Tigger on September 03, 2019, 09:21:46 AM
And the PV raft would help to reduce evaporation too so an extra bonus  ;D


Title: Re: Draining Every Hydropower Dam in The US For Solar Panels
Post by: sam_cat on September 03, 2019, 10:16:54 AM
And the PV raft would help to reduce evaporation too so an extra bonus  ;D

And the evaporation that does occur helps to keep the panels cool, helping keep them on a nice point on the temperature curve. :)