Hybridisation of Electricity Grids (combining stable and variable sources)

Brid Hegarty

I'm sure some of you have heard of the concept of the 'baseload' within an electricity grid, which is the minimum amount of electricity that the grid needs. This is what it looks like in brown in the image below: 

The problem with renewables here is that if too many people are generating their own energy from solar panel, that it causes negative demand and that the new graph would look like this:

I recently came across this argument that a conspiracy theorist made about adopting renewables. it contains a large amount of truth to it... albeit most likely taken out of context. His argument is quoted below.

For anyone unfamiliar, this is the "duck curve", the main difficulty with adopting renewables. It is the net energy demand minus solar. Your supply of electricity can only be a teeny tiny bit greater or less than demand, otherwise electric grid components, e.g. transmission start to break. You can see quite clearly how California generates so much solar that it is digging a "hole" in the energy demand. It has only worsened since that graph in 2020.

Unless we make absolutely, completely monstrous industrial scale batteries that don't degrade over time, I don't see how solar can even be adopted. Sure it's cool that you can get a panel that just soaks in the sun and you power things with it, but the Congo is already basically enslaved and we don't have a tenth as much battery material as we'd need to spread out the demand.

The only system we have that can really deal with that 13,000 mW ramp is natural gas. So the more we add solar to the grid, ironically the more we incentivize natural gas. I think most environmentalists are well-meaning, they just haven't had people explain these problems in a clear way. That, or they just have their heads buried too deep in their woke religion to hear, "trade-offs exist"

Thank you

Capt'n Midnight

In practice minimum demand on Sunday night here was 3,125 MW and 75% of that could have been supplied by renewables so our "baseload"of guaranteed demand is 11% of the maximum demand of 7,031 MW. https://www.smartgriddashboard.com/#all/demand ( The 292MW of Turlough hill could have allowed another 876MW of renewables on the grid , leaving "baseload" at just 6% )

The 2030 target is to reduce emissions by 80%. So the overall amount of gas that will be burnt will be less. It's that simple.

Our grid can handle up to 75% non-synchronous generation. One way to look at it is that for every Watt of thermal or hydro electricity we can adsorb 3 Watts of renewables. And at times we've been able to export that 25% over the interconnectors.

The zero emissions target date is 2050 so gas can continue to be used until then. But that gas will have more hydrogen and bio-methane over time.

NB The Single Energy Market operational constraints are here https://www.sem-o.com/publications/general-publications/

Until there's a lot of synchronous compensators rolled out our grid will need geographically dispersed high inertial generators on load at all times for System Stability. So there's a certain amount of power that needs to be generated by hydro and thermal generators until then.

Thanks to better computers and weather satellites wind forecasts are getting better. This is last month. The operational constraints already have running gas turbines at reduced power so they can ramp up in seconds. Turlough Hill can respond in about 10 seconds if the turbines are already spinning in air. Batteries are way, way faster. Interconnectors are slow to respond but they are another option.

josip

Renewables accounted for more than 50% of our electricity generation in December. Does anyone know the percentage for the whole of 2023? I'm expecting it to be less but hoping it's more than the 37% in 2022, maybe even more than the 40% during 2020-Covid.