My counterpoint would be that efficiency isn't always the most important variable in an energy supply chain, especially when your energy supply is renewable, an

My counterpoint would be that efficiency isn't always the most important variable in an energy supply chain, especially when your energy supply is renewable, and thus non-polluting, and as the marginal cost for generation of renewable energy continues to drop. There are many situations where it would be much less expensive and simpler to replace a coal- or oil-fired boiler with one that runs off of iron filings, while still maintaining all of the rest of the equipment as-is. These locations could be off the grid, or in locations where it's not feasible to get a connection capable of supplying the megawatts of electricity it might take to produce enough steam.