1,836 research outputs found
The Global Grid
This paper puts forward the vision that a natural future stage of the
electricity network could be a grid spanning the whole planet and connecting
most of the large power plants in the world: this is the "Global Grid". The
main driving force behind the Global Grid will be the harvesting of remote
renewable sources, and its key infrastructure element will be the high capacity
long transmission lines. Wind farms and solar power plants will supply load
centers with green power over long distances.
This paper focuses on the introduction of the concept, showing that a
globally interconnected network can be technologically feasible and
economically competitive. We further highlight the multiple opportunities
emerging from a global electricity network such as smoothing the renewable
energy supply and electricity demand, reducing the need for bulk storage, and
reducing the volatility of the energy prices. We also discuss possible
investment mechanisms and operating schemes. Among others, we envision in such
a system a global power market and the establishment of two new coordinating
bodies, the "Global Regulator" and the "Global System Operator".Comment: Manuscrip
Recommended from our members
The role of smart sensor networks for voltage monitoring in smart grids
The large-scale deployment of the Smart Grid paradigm will support the evolution of conventional electrical power systems toward active, flexible and self-healing web energy networks composed of distributed and cooperative energy resources. In a Smart Grid platform, distributed voltage monitoring is one of the main issues to address. In this field, the application of traditional hierarchical monitoring paradigms has some disadvantages that could hinder their application in Smart Grids where the constant growth of grid complexity and the need for massive pervasion of Distribution Generation Systems (DGS) require more scalable, more flexible control and regulation paradigms. To try to overcome these challenges, this paper proposes the concept of a decentralized non-hierarchal voltage monitoring architecture based on intelligent and cooperative smart entities. These devices employ traditional sensors to acquire local bus variables and mutually coupled oscillators to assess the main variables describing the global grid state
Scalability tests of R-GMA-based grid job monitoring system for CMS Monte Carlo data production
Copyright @ 2004 IEEEHigh-energy physics experiments, such as the compact muon solenoid (CMS) at the large hadron collider (LHC), have large-scale data processing computing requirements. The grid has been chosen as the solution. One important challenge when using the grid for large-scale data processing is the ability to monitor the large numbers of jobs that are being executed simultaneously at multiple remote sites. The relational grid monitoring architecture (R-GMA) is a monitoring and information management service for distributed resources based on the GMA of the Global Grid Forum. We report on the first measurements of R-GMA as part of a monitoring architecture to be used for batch submission of multiple Monte Carlo simulation jobs running on a CMS-specific LHC computing grid test bed. Monitoring information was transferred in real time from remote execution nodes back to the submitting host and stored in a database. In scalability tests, the job submission rates supported by successive releases of R-GMA improved significantly, approaching that expected in full-scale production
Monte Carlo radiative transfer in SPH density fields
We combine a Monte Carlo radiative transfer code with an SPH code, so that --
assuming thermal equilibrium -- we can calculate dust-temperature fields,
spectral energy distributions, and isophotal maps, for the individual
time-frames generated by an SPH simulation. On large scales, the radiative
transfer cells (RT cells) are borrowed from the tree structure built by the SPH
code, and are chosen so that their size -- and hence the resolution of the
calculated temperature field -- is comparable with the resolution of the
density field. We refer collectively to these cubic RT cells as the 'global
grid'. The code is tested and found to treat externally illuminated dust
configurations very well. However, when there are embedded discrete sources,
i.e. stars, these produce very steep local temperature gradients which can only
be modelled properly if -- in the immediate vicinity of, and centred on, each
embedded star -- we supplement the global grid with a 'star grid' of closely
spaced concentric RT cells.Comment: Accepted by A&
Managing community membership information in a small-world grid
As the Grid matures the problem of resource discovery across communities,
where resources now include computational services, is becoming more
critical. The number of resources available on a world-wide grid is set to grow
exponentially in much the same way as the number of static web pages on
the WWW. We observe that the world-wide resource discovery problem can
be modelled as a slowly evolving very-large sparse-matrix where individual
matrix elements represent nodes’ knowledge of one another. Blocks in the
matrix arise where nodes offer more than one service. Blocking effects also
arise in the identification of sub-communities in the Grid. The linear algebra
community has long been aware of suitable representations of large, sparse
matrices. However, matrices the size of the world-wide grid potentially number
in the billions, making dense solutions completely intractable. Distributed
nodes will not necessarily have the storage capacity to store the addresses of
any significant percentage of the available resources. We discuss ways of modelling
this problem in the regime of a slowly changing service base including
phenomena such as percolating networks and small-world network effects
Global Opportunities to Increase Agricultural Independence Through Phosphorus Recycling
Food production hinges largely upon access to phosphorus (P) fertilizer. Most fertilizer P used in the global agricultural system comes from mining of nonrenewable phosphate rock deposits located within few countries. However, P contained in livestock manure or urban wastes represents a recyclable source of P. To inform development of P recycling technologies and policies, we examined subnational, national, and global spatial patterns for two intersections of land use affording high P recycling potential: (a) manure‐rich cultivated areas and (b) populous cultivated areas. In turn, we examined overlap between P recycling potential and nation‐level P fertilizer import dependency. Populous cultivated areas were less abundant globally than manure‐rich cultivated areas, reflecting greater segregation between crops and people compared to crops and livestock, especially in the Americas. Based on a global hexagonal grid (290‐km2 grid cell area), disproportionately large shares of subnational “hot spots” for P recycling potential occurred in India, China, Southeast Asia, Europe, and parts of Africa. Outside of China, most of the remaining manure‐rich or populous cultivated areas occurred within nations that had relatively high imports of P fertilizer (net P import:consumption ratios ≥0.4) or substantial increases in fertilizer demand between the 2000s (2002–2006) and 2010s (2010–2014). Manure‐rich cultivated grid cells (those above the 75th percentiles for both manure and cropland extent) represented 12% of the global grid after excluding cropless cells. Annually, the global sum of animal manure P was at least 5 times that contained in human excreta, and among cultivated cells the ratio was frequently higher (median = 8.9). The abundance of potential P recycling hot spots within nations that have depended on fertilizer imports or experienced rising fertilizer demand could prove useful for developing local P sources and maintaining agricultural independence
- …