I have huge respect for Dr. Eddie O Connor but I think he is missing the need for Demand Response. DR is a vital requirement for deep renewable penetration as well as large super grids. I just listened to his address at ASPO-Ireland. He explained that if a wind based grid was large enough then production would be level. Even if this is true, demand is not flat.
I understand that Ireland wants to have 33% renewables by 2025. Since wind farms yield 30% of rated output this means that we will have 110% installed plant versus our average consumption. Given that currently the consumption variation from minimum to maximum is nearly 200% this means that at certain times we will be generating, from wind alone, 146% of our demand. Clearly that will result in large periods of wind farm curtailment.
As far as I know curtailment was planned to start from this summer for wind farms and we are only on 9% renewables at the moment.
If we are indeed peaking on fossil fuels then 33% renewables is not a destination. It is part of the journey. We need to get to a market of renewables plus nuclear eventually. Even if we have large interconnects from Africa to Iceland we need huge amounts of DR to make this possible.
The electrical grid system has evolved over the last 100 years as a flexible supply designed to meet inflexible but fairly predictable demand. Complicated trading systems have evolved to meet the needs of this flexible supply / inflexible demand market. DR is seen as an ‘ancillary service’. It allows for margins of error or enables peak shaving. However most users continue to use electricity on a single tariff and care little about DR. What if the grid, as we know it, didn’t exist? What if it was being developed from scratch now and the only sources of power were solar, wind, hydro, tidal and wave? This would be described as inflexible supply and demand would have to respond to the variability in supply. In order for this grid to be stable there would have to be huge demand response capability built in. You cannot have inflexible supply and inflexible demand.
To my way of thinking the solution is to have realtime pricing on electricity. It may be necessary to let the price of electricity go near zero or even negative at some times to stimulate new markets such as resistive heating and H2 production. Resistive heating as a way of replacing fossil fuel consuption is far better from a carbon perspective than curtailing the wind farms. An obvious market would be municipal swimming pools and public buildings.
Variable pricing will create new markets for low cost electricity and will create both new generation at high cost times (ie CHP or embedded diesel generation) as well as devices that can load shift (ie HVAC and refrigeration).
It is therefore my thesis that DR based on real time pricing is the enabling technology required to move us to a renewables future.