I have very limited understanding of ecat other than it generates cheap heat. The issue for municipal scale deployment will be storing the heat energy and generating electricity.
Isentropic.com has a solution for Pumped Heat Electricity Storage.
Isentropic has designed a system that uses the Isentropic heat pump to store electricity in thermal form ("Pumped Heat"). The storage comprises two large containers of gravel, one hot (500C) and one cold (-150C). Electrical power is input to the machine, which compresses/expands air to (+500C) on the hot side and (-150C) on the cold side. The air is passed through the two piles of gravel where it gives up its heat/cold to the gravel. In order to regenerate the electricity, the cycle is simply reversed. The temperature difference is used to run the Isentropic machine as a heat engine.
The round trip efficiency is over 72% - 80%. Because gravel is such a cheap and readily available material, the cost per kWh can be kept very low - $55/kWh - and $10/kWh at scale.
Compared to Pumped Hydro
Bath County Pumped Storage, Virginia, USA. Two reservoirs covering 820 surface acres (3.32 sq.km). 30 GWh storage capacity (largest in the world). Pumped Heat Storage Plant of the same capacity would occupy 1/300th of the area.
Benefits of PHES
Low Cost
High Efficiency
Not geographically constrained
Safe and environmentally inert
Modular and scalable
Rapid response to load variation