21,400 research outputs found

    Financing schemes for residential, grid-connected PV solar systems in BCS, Mexico

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    This article presents two proposals to spur the extensive adoption of grid-connected, residential, solar photovoltaic systems in the Mexican state of Baja California Sur. To this aim, electricity generation costs and subsidies were estimated first, together with time-of-generation avoided costs that could result from the implementation of such solar systems. An overview of financing mechanisms for solar and other renewable energies around the world is also presented followed by current mechanisms available in Mexico. The first proposal is centered around the operation of a solar energy service company that would receive the avoided cost of generation as compensation in return for sourcing, installing, and maintaining solar PV systems on residential users’ roofs. This would free up the residential user from any future electricity payments. The second proposal consists in the implementation of a feed-in tariff (FiT), currently unavailable in Mexico for residential users. The FiT could be funded from the avoided generation cost in conventional plants plus the corresponding savings from self-generation of electricity. Alternatively, the option of funding the FiT from small increases in electricity prices to all customers was also explored. Present value analyses suggest that both proposals are worthwhile pursuing in Baja California Sur

    Alternating Hamiltonian cycles in 22-edge-colored multigraphs

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    A path (cycle) in a 22-edge-colored multigraph is alternating if no two consecutive edges have the same color. The problem of determining the existence of alternating Hamiltonian paths and cycles in 22-edge-colored multigraphs is an NP\mathcal{NP}-complete problem and it has been studied by several authors. In Bang-Jensen and Gutin's book "Digraphs: Theory, Algorithms and Applications", it is devoted one chapter to survey the last results on this topic. Most results on the existence of alternating Hamiltonian paths and cycles concern on complete and bipartite complete multigraphs and a few ones on multigraphs with high monochromatic degrees or regular monochromatic subgraphs. In this work, we use a different approach imposing local conditions on the multigraphs and it is worthwhile to notice that the class of multigraphs we deal with is much larger than, and includes, complete multigraphs, and we provide a full characterization of this class. Given a 22-edge-colored multigraph GG, we say that GG is 22-M\mathcal{M}-closed (resp. 22-NM\mathcal{NM}-closed)} if for every monochromatic (resp. non-monochromatic) 22-path P=(x1,x2,x3)P=(x_1, x_2, x_3), there exists an edge between x1x_1 and x3x_3. In this work we provide the following characterization: A 22-M\mathcal{M}-closed multigraph has an alternating Hamiltonian cycle if and only if it is color-connected and it has an alternating cycle factor. Furthermore, we construct an infinite family of 22-NM\mathcal{NM}-closed graphs, color-connected, with an alternating cycle factor, and with no alternating Hamiltonian cycle.Comment: 15 pages, 20 figure
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