OneWedge

Most RE critics point out that the current state of electric grids is such that we risk their breakdown: a good excuse to further delay the transition, calling for “the grid first”.

As an engineer, I cannot ignore the obvious challenges posed by the progressive electrification of primary energy consumption: while today the world consumes about two thirds of its primary energy in forms other-than-electric (chemical, heat, etc) and therefore use other means of transportation (primarily pipelines, ships, trucks and trains), it’s enough to imagine a simple reversal of that fraction to understand that we do not have enough cables in place to take energy from where it’s generated to where it’s consumed, so let me join the chorus:

“Invest in the grid”

However, that’s where my agreement stops, because I think that distributed generation is actually LESS stressful on the grid than the traditional one: you see an extreme case in the PV system on your roof, where there is ZERO grid impact.

Size matters

Of course I know that utility scale solar or wind farms (esp. offshore) also need to be connected, but each farm is significantly smaller than, say, a modern Nuclear Power Plant.

The average wind turbine has a 3MW nameplate capacity and while colossi such as the 20GW Gansu Wind Farm exist, statistics tell us that the in the U.S. there are 72,000 utility scale wind farms with a collective nameplate capacity of 142GW generating about 425TWh of energy – that means that the average farm generates 6GWh.

[EDIT 10/3: I added two columns with the nameplate capacity, because the grid connection needs to support the peak power from a plant – conclusions unchanged]

(All data are referred to U.S., 2022)

Generation technology	# of plants	Energy generated (TWh/y)	Energy per plant (GWh)	Nameplate power (GW)	Power per plant (MW)
Wind farms	72,000	425	6	142	2
Solar farms	2,500	165 (*)	50 (est.)	72	29
Dams + pumped hydro	1,490	240	161	103	69
Coal-fired	217	675	321	198	912
Natural gas-fired	987	1,802	547	497	503
Nuclear	54	775	14,350	95	1,759

In other words, adding generation assets in Renewables creates a grid problem hundreds if not thousands times smaller than adding the same capacitu in non-renewables. BTW this does not happen by chance, as all fossil + nuclear generation facilities are essentially made by an heat stage (something which heats water) and a vapor stage (where high-pressure vapor turns a turbine which generates electricity) and decades of engineering have decided that the vapor stage sweet area (not really a “spot”) ranges from 500 to 2.000 MW , so that’s the size range thermal power plants are targeting to optimize capex.

No vapor stage either in wind or solar, which are therefore much more flexible and, being built of “Lego-brick” small individual units, can range in size much more widely.

My conclusion

Once you accept the need to transition away from fossil fuels, distributed generation (i.e. solar and wind) is actually hundreds of times less stressful on the grid, simply because each new generation asset creates an orders of magnitude smaller problem to transport the energy from where it’s created to where it’s used.