Brittle Power- PARTS 1-3 (+Notes) - Natural Capitalism Solutions

Chapter Thirteen: Designing for Resilience 195autonomous—able to stand alone at need, so that it can continue to do at leastpart of its normal work without its usual interconnections. Thus a faulty componentcould be cut off from the interconnections which otherwise couldpropagate “sympathetic” failures to other components, yet after the failurewas thus isolated, the remaining components could still work.This is one reason why electric grids have power dispatchers who, if apower station malfunctions, can trip it off the grid (if automatic relays havenot already done so), isolate the fault, and call in spare capacity elsewhere totake its place. (At least that is what is supposed to happen; but as the NewYork blackout showed, a grid designed to be reliable in the face of defined,predicted kinds of technical failure can lack resilience when confronted withsome other kind. As noted in Chapter Ten, today’s power grids are brittle inmany other respects too.Such “selective coupling” is common in biology. Contrary to popularbelief, organisms in an ecosystem do not always tend to increase their interdependencewherever possible. In fact, they frequently limit it or make itoptional. They also often store up food to “buffer” against an interruption inan accustomed food source.The key principle here, then, is that modules should be interconnected in away that normally provides the benefits of cooperation, but in case of failure canbe readily decoupled. The federation of modules should be loose, not tight.Thus failures can be confined and repaired without impairing the whole system.Diversity A second important way to limit damage is to try to ensure thatdifferent components will fail in different ways, rather than being mown downen masse by a single event. This implies components of diverse (heterogeneous)types. A car’s parking brake is not simply a duplicate hydraulic brake; it iscoupled differently (mechanically) and redundantly (by a separate linkage) sothat even if the normal hydraulic brakes fail, there is a different alternativethat does not depend on brake lines, master cylinder, brake fluid, and so on.The parking brake is not designed for routine use to stop the car, but it canserve as an emergency brake at a pinch—because of its diversity of design.The human body provides numerically redundant kidneys and lungs, plusconsiderable built-in redundancy (spare capacity) in the unreplicated liver andheart. There need be, however, only one spleen—because certain structures inthe liver can gradually take over the spleen’s essential functions if needed. 61Thus the trouble of making a spare spleen is avoided.Such functional flexibility has counterparts in the energy system. The Swedishgovernment, for example, requires that new boilers be able to accept solid fuel(coal, wood, etc.) even if their normal fuel is oil or gas, and requires also that the