What does this mean? I thought all electric heaters were essentially 100% efficient, due to conservation of energy.
What is striking to me, is that roughly 50% of Texas have gas furnaces and most of the rest have electric resistance heating. Nearly everyone has an AC. There was more demand for electricity from those using electric heaters during the cold snap than in the summer from AC's when the state has an average temperature near a hundred. It would probably be worth it to subsidize a heat pump for anyone stuck with resistance heating.
Well, gas heaters are a lot more than 100% efficient in terms of heating per unit of electricity consumed, so better for the grid.
(Before anyone else points it out, yes, electric heat pumps are usually more than 100% efficient, too, but that's not relevant here because in severe cold, they are less efficient than direct heating.)
If this was about northern Canada or other such climates you would have a good point.
Mitsubishi's residential air-source ductless mini-split heat pumps that have their "Hyper-heating inverter" technology are greater than 100% down to at least -13℉ (-25℃), although their capacity starts dropping fairly linearly from 100% at 23℉ (-5℃) to 76% at -13℉ (-25℃), so unless you oversized your system a bit you might have to put up with your house being a few degrees cooler when it gets very cold outside for a long time.
Their efficiency remains above 180% down to around -5℉ (-20℃).
In most of the major cities of Texas these would have worked fine and remained around 200% or higher efficiency and around 90% capacity. Only a small number of people would have had them get down to 100% efficiency.
Fujitsu and Daikon have similarly performing heat pumps.
They look like large baseboard heaters, and inside have a bunch of ceramic bricks which can store a lot energy. During off peak periods the heaters can 'charge', i.e. heat up the bricks, then after that the heat is slowly released over time. Modern versions have a small fan to assist releasing heat, controlled by a thermostat or other smarts.
The thing is though, these can store a lot of energy. My parents had a new one installed last year which stores 24 kWh of heat:
https://www.elnur.co.uk/product/ecombi-hhr-high-heat-retenti...
Potentially these (the charging can be controlled by a smart meter) could have reduced the electricity demand during peak times.
For example, geothermal electric heat pumps typically achieve greater than 300% efficiency in terms of thermal energy delivered per electric energy consumed.