The reference system design provides no mechanism for frequency or power level regulation by means of the SPS; it is assumed that the SPS will normally be operated at its maximum available power. As a consequence, the regulation burden will have to be carried by the conventional units in the system. This may be a limiting factor on SPS penetration. RELIABILITY: The use of an SPS in a utility system might either increase or decrease the reserve margin required to maintain a given reliability standard, depending on how reliable the SPS is. A much more careful and complete failure analysis of the SPS must be conducted before a confident determination of its effect on reserve margin can be made. Modes leading to complete or substantial loss of the SPS output are particularly important since they will have the greatest impact on reliability. Should it prove to have high reliability compared to conventional units, the SPS will impose a correspondingly high reliability requirement on its associated transmission network. This presumably will be accomplished by a greater than usual degree of transmission line redundancy. MAINTENANCE: Maintenance will surely be one of the major problems of the SPS. For example, there are about seven billion diodes in a rectenna and their mean time to failure is estimated to be 30 years. Assuming an exponential failure law, the expected number of failures per years is approximately 200,000. This would lead to a corresponding degradation in performance of about 3%/year unless failed diodes are regularly replaced. Locating and replacing 200,000 diodes per year would appear to be a Herculean task. RISK: There are several kinds of risk associated with SPS. A very significant risk involves the opportunity cost of the SPS. If financial and other resources are committed to the SPS, then some other opportunities must be foregone since resources are limited. Since the resources needed to develop the SPS are quite substantial, the associated risk may be significant, and should be carefully evaluated. A utility (or utilities) expecting to incorporate the SPS into its system must plan and start constructing the appropriate transmission lines and complementary generation plants several years in advance of the anticipated SPS completion date. If, for any reason, the SPS cannot be completed on time, does not operate as designed, or is cancelled, then the utility will not only face a substantial economic loss, but will also find it difficult to make up for the lost capacity. Thus, utilities will be wary of SPS until it has been demonstrated to be constructable on schedule and reliable in operation.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==