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The Global Grid

Spyros Chatzivasileiadis, Damien Ernst, Göran Andersson

arXiv:1207.4096v4eess.SYcs.SYphysics.soc-ph

TL;DR

The electricity grid remains largely regional, while renewable resources increasingly lie far from load centers. The paper proposes a global transmission backbone and reports that importing renewable power can be more economical than operating some US fossil-fuel plants.

  • Problem

    Electricity-grid interconnections have largely remained regional or interregional, despite remote renewable resources and load centers spanning continents.

    Source: §1 · p. 2

  • Method

    The paper introduces a transmission-centered Global Grid concept and discusses investment options and a hierarchical market with a Global System Operator.

    Source: §4 · p. 7, §5.1 · p. 8, §7 · p. 10

  • Results

    Except for the most expensive RES generators, importing RES power from Europe would be more economical for the US than operating its own fossil-fuel power plants.

    Source: §7 · p. 10

  • Takeaways & Limitations

    Intercontinental links can mitigate renewable supply-demand mismatches by delivering power where demand is higher at that time.

    Source: §3.1 · p. 4

    New network couplings could also propagate disturbances, so preventing a rare global blackout remains a challenge to address.

    Source: §3.5 · p. 6

Abstract

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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".

1. Introduction

Earlier work examined renewable-energy targets, regional interconnections, and long-distance transmission from remote resources. This paper proposes a globally interconnected grid and frames its transmission technology, investment, and operation as the focus.

1. Introduction

  • Prior studies argued that renewable integration requires transmission reinforcement, including 1700-3600 km of additional lines in Germany and neighboring regions for a 39% RES scenario.Interconnection of 19 dispersed wind sites was associated with 33% of yearly average wind power usable at conventional-plant reliability.Source: §1 · p. 1
  • Studies also considered long-distance renewable transmission, including Congo-to-Italy hydro and Iceland-to-UK geothermal and hydro projects.Earlier work described some such proposals as feasible and economically competitive, and demonstrated profitability for Iceland-to-UK generation.Source: §1 · pp. 1–2
  • Many earlier proposals and projects targeted regional or interregional interconnections, leaving the electricity grid as a major network without worldwide links.The paper contrasts this with transportation and telecommunications networks that already span the globe.Source: §1 · p. 2
  • The Global Grid would connect remote renewable generation to load centers as renewable sites move farther from existing grids.The paper uses a Greenland wind farm equidistant from Europe and North America as an example, and reports that connecting it to both can be profitable.Source: §1 · p. 2
  • The paper introduces the Global Grid from a transmission-focused technological perspective, then considers its opportunities, investments, and possible operating schemes.Its planned discussion covers the concept, power-engineering opportunities, investment mechanisms, and market structures.Source: §1 · p. 2

2. The Global Grid: An Illustration

The Global Grid is envisioned as a meshed backbone connecting regional power systems and remote renewable plants. A Greenland wind-farm example illustrates how intercontinental links might be built and evaluated.

2.1. Generation – Extreme RES

  • “Extreme RES” means renewable plants in harder-to-install locations or using technology that is not yet mature.Examples include airborne turbines, deep-ocean installations, and Antarctic plants.Source: §2.1 · p. 2

2. The Global Grid: An Illustration

  • The proposed grid is a meshed transmission backbone linking regional power systems, allowing parties to transmit power across the network.The paper expects most links to use HVDC, which supports long-distance submarine transmission and has lower thermal losses than AC lines.Source: §2.2 · p. 3

2.2. Transmission

  • HVDC is proposed for most links because it enables long-distance submarine cables, connects asynchronous systems, and has lower thermal losses than AC lines.Some land links within synchronous systems could instead use UHVAC or short Gas-Insulated Line segments.Source: §2.2 · p. 3
  • Several required technologies are relatively mature, but multi-terminal systems, deep-sea bulk cables, breakers, protection, and control still need development.The authors anticipate two or three operating voltage levels for a global grid.Source: §2.2 · p. 3

2.3. Wind Farm in Greenland

  • A 3 GW Greenland wind farm linked to Europe and North America could be profitable under the paper’s assumed peak-price sales and trade opportunities.The analysis estimates 21%-25% higher delivered-kWh costs for dual-continent connection and 31%-33% higher revenues if off-peak prices are half peak prices; the route could transmit about 20 TWh annually versus roughly 10 TWh produced.Source: §2.3 · p. 4

3. Opportunities

The Global Grid’s opportunities arise from harvesting remote renewables through intercontinental links. The paper discusses how those links could balance supply and demand, reduce reserve and storage needs, affect prices and system security, and create wider economic benefits and challenges.

3.1. Smoothing Out Electricity Supply and Demand

  • Up to 50% of daily peak demand may fall away at night; time-zone offsets could redirect surplus renewable power and potentially allow 100% annual exploitation of RES potential.The paper estimates a 5500 km, 3 GW submarine cable at €0.0166–€0.0251 per delivered kWh, and a Halifax–Oporto-distance cable at €0.013/kWh; it argues importing RES power from Europe could be cheaper for the US than fossil generation except for the most expensive RES generators.Source: §3.1 · p. 4

3.2. Minimizing Power Reserves

  • Interconnections were reported to reduce dispatchable conventional-plant needs by two to eight times in European and potential global grids, while cross-continental reserve sharing could lower generation costs and losses.The authors argue that reserves shared across interconnected systems could limit the effect of a lost global link compared with losing a power plant in one control area.Source: §3.2 · p. 5

3.3. Alleviating the Storage Problem

  • A 6000 km HVDC line is estimated to be more efficient than pump-hydro or compressed-air storage, while links can move excess power to regions that need it.The estimated line losses are about 3% per 1000 km; even storage able to absorb all excess power would leave 65% of proposed grid reinforcements necessary, and coordinated links and reinforcements could yield savings.Source: §3.3 · p. 5

3.4. Reducing the Volatility of the Electricity Prices

  • Interconnections could mitigate extreme electricity prices by supplying shortages or moving surplus, but NorNed analyses found no significant price-level change and suggest much greater capacity may be needed.The authors speculate that mean prices may fall, while noting that price-data studies are needed to assess effects more accurately.Source: §3.4 · pp. 5–6

3.5. Enhancing Power System Security

  • The Global Grid could relieve congestion and improve resilience through additional routes and controllable HVDC support, but poor design may congest the AC grid and disturbance propagation remains a challenge.The paper identifies multiple injection points and reinforcement of weak AC-network locations as ways to manage flows; HVDC converters may also support voltage stability and transient stability.Source: §3.5 · p. 6

3.6. Additional Benefits and Challenges

  • HVDC links can overlay existing AC grids to deliver bulk power directly with fewer losses and without overloading other lines or substations; importing green power may benefit high-demand countries with high carbon footprints and limited RES potential.The paper notes that conventional fuel costs, including carbon taxes, may rise relative to RES operating costs.Source: §3.6 · p. 6
  • Global links could stimulate investment and local benefits in regions with abundant renewables, while multiple pathways could diversify supply and strengthen competition; overseas dependence, terrorism, and political unrest remain concerns.The paper points to African desert solar power serving local energy needs or desalination, and argues that multiple pathways could reduce dependence on particular countries for primary energy.Source: §3.6 · p. 6

4. Investments

The paper argues that long intercontinental links can be economically competitive, while proposing investment models suited to their scale and risk. It anticipates regulated investment for most such cables, complemented by merchant projects and subsidies, but identifies market volatility and regulation as challenges.

4. Investments

  • At 5,500 km, delivered-kWh cable revenue could exceed estimated cost by two to four times under assumptions based on NorNed revenues.NorNed generated €50 million in its first two months, about 12% of invested capital.Source: §4 · p. 7

4.1. Investment Mechanisms

  • Regulated investment is the common transmission model, while merchant investment is another option; mixed regulated and merchant capacity is also anticipated.The paper notes that NorNed and BritNed appear to follow the merchant model and that a mixed scheme is provided for in EC regulations.Source: §4.1 · p. 7

4.2. Investments in the Global Grid

  • Most long intercontinental cables are expected to use regulated investment because their capital intensity and risk may deter private consortia.The paper argues that cost-competitive renewable interconnections could increase social welfare and qualify for regulated investment.Source: §4.2 · p. 7
  • Daily spot-market arbitrage may be competitive when peak–off-peak price differences exceed €30/MWh, while long-term contracts may not be profitable under current conditions.The paper expects significant line profits to come from intra-day spot-market arbitrage as renewable intermittency increases uncertainty in delivered energy.Source: §4.2 · p. 7
  • Merchant investors could develop smaller regional links that complement an intercontinental line and enable further network expansion.Alternative routes could create competition between lines.Source: §4.2 · p. 7
  • More interconnections could reduce price volatility and discourage merchant investment, though the paper says that effect may be harder to achieve across global networks.NorNed showed no significant price effect in its first two years, and substantially greater capacity may be needed to reduce volatility.Source: §4.2 · p. 8
  • Subsidies or a mix of regulated and merchant investment are also proposed, with the NordBalt subsidy offered as an example.The EU provided €131 million toward NordBalt’s €550 million budget; the paper suggests scaled-up subsidies could be envisioned for Global Grid links.Source: §4.2 · p. 8
  • Designing regulation that permits merchant projects while addressing investment challenges remains a significant research challenge.The paper says regulation—or non-regulation—of Global Grid investments remains unresolved.Source: §4.2 · p. 8

5. Operation

The paper sketches a global electricity-market structure, including coordinating bodies and alternative market designs, while identifying unresolved operational, market, and security questions. It envisages a shift from decentralized coordination toward more centralized trade coordination as the grid becomes meshed.

5.1. Organization of a Global Market Environment

  • A Global Regulator is proposed to coordinate regional regulators, organize communication, coordinate investments, and help ensure competitive markets.The Global System Operator could assume responsibilities similar to those of existing Independent System Operators.Source: §5.1 · p. 8
  • As the grid becomes meshed, trade coordination could centralize; early interconnections could instead use explicit auctions or implicit market coupling.The paper presents both decentralized and centralized operation as possible stages or schemes.Source: §5.1 · p. 8
  • The proposed global market could use either a hierarchical model that clears DC-grid trade before regional AC markets, or a simpler global exchange that does not account for induced flows.The hierarchical model preserves regional market structures, whereas the horizontal exchange keeps market-clearing complexity low.Source: §5.1 · p. 8
  • Global-grid users could bid active or reactive power in regional ancillary-services markets, and a global ancillary-services market is also envisioned.The paper notes that HVDC lines might buy control power from another control market as a form of arbitrage.Source: §5.1 · p. 8

5.2. Challenges in Operation

  • Operational design questions include allocating capacity across parallel HVDC links, coupling or harmonizing regional markets, and preventing market power by producers or link owners.The paper also asks how prices should be set at multi-terminal nodes.Source: §5.2 · pp. 8–9
  • More renewable generation may shift price patterns toward renewable availability and residual demand, while regional residual-demand differences could benefit from global interconnections.The paper calls for more detailed study of price fluctuations under increased renewable integration.Source: §5.2 · p. 9
  • Security work should examine adapting control mechanisms to the HVDC overlay, the need for HVDC control power, and global-blackout risks and prevention.The paper identifies these as issues for further study rather than settled operational outcomes.Source: §5.2 · p. 9

6. Discussion

The discussion frames the Global Grid as one possible response to a future with more renewable generation, especially by connecting remote resources to load centers. It argues that this option may complement regional renewable development, while requiring further evaluation against alternatives.

6. Discussion

  • The paper considers increasing renewable penetration plausible amid environmental concerns, oil-supply concerns, and rising prices, and presents the Global Grid as one likely alternative.It does not treat the grid as the only option for future global energy supply.Source: §6 · p. 9
  • Remote renewable resources could become competitive with new installations near load centers if technology-cost reductions flatten or resource quality declines.The paper cites a possible future break-even point between remote resource harvesting and nearby renewable installations.Source: §6 · p. 9
  • Gas pipelines and hydrogen are alternatives for transporting energy, with gas offering longer-term storage and hydrogen conversion described as relatively inefficient.The paper reports an approximately 32% round-trip efficiency for producing hydrogen from electricity and converting it back to electricity.Source: §6 · p. 9
  • The authors argue that regional grid reinforcements should be planned with possible global-grid synergies in mind as HVDC networks expand.They say regional systems should explore opportunities from a meshed global HVDC grid as larger regions become connected.Source: §6 · p. 9

7. Conclusions

The conclusion presents the Global Grid as a backbone for delivering remote renewable electricity to load centers and reports an economic comparison for a Europe–North America cable. It calls for further technical, economic, societal, and regional feasibility studies, including quantification of project risks.

7. Conclusions

  • The proposed global transmission backbone would connect remote renewable generation, including North Sea and African desert resources, to load centers.The paper describes its contribution as a technological introduction to the concept and a brief discussion of investment and market operation.Source: §7 · pp. 9–10
  • A submarine cable connecting Europe and North America would make importing renewable power more economical for the US than operating its fossil-fuel plants, except for the most expensive renewable generators.The paper presents this as the result of its studied cable scenario.Source: §7 · p. 10
  • The authors call for working groups and more detailed technical, economic, societal, and regional feasibility studies that quantify project risks.They also propose research to develop methods and tools addressing emerging Global Grid problems.Source: §7 · p. 10

Appendix A. Cost of a Long-Distance Submarine Cable

Appendix A estimates long-distance submarine HVDC transmission costs using assumptions on cable costs, losses, availability, and utilization. Its scenario estimates are compared with costs from existing and planned projects.

Appendix A. Cost of a Long-Distance Submarine Cable

  • Each terminal converter is assumed to cost €300 million, reflecting the line’s higher voltage and large capacity.The cited cost references include submarine cable estimates up to €2,500 million per 1,000 km and converter estimates of €250–350 million.Source: Appendix A · p. 10
  • The cost projections in are slightly overestimated but align with calculated costs for existing projects.The passage also says assumptions in [12] are consistent with NorNed and compares projections in with Table A.1.Source: Appendix A · p. 10, Table A.1 · p. 11
  • Calculations assume 3% line losses per 1,000 km, 0.6% terminal losses, 99% availability, a 40-year lifetime, and a 3% discount rate.They also assume four hours per day at half capacity during flow reversals, yielding about 83% utilization; the ramping constraint is necessary for CSC-HVDC, not VSC-HVDC.Source: Appendix A · p. 11
  • €0.0166/kWh in the low-cost scenario and €0.0251/kWh in the high-cost scenario; for 4,400 km, the estimate falls to €0.013/kWh.The scenarios assume a 3,000 MW, ±800 kV cable over 5,500 km, with line costs of €1.15 million/km and €1.8 million/km, respectively.Source: Appendix A · pp. 10–11

Appendix B. Transmission Costs for a Wind Farm in Greenland

Appendix B estimates transmission costs for a 3 GW Greenland wind farm connected to North UK and, optionally, North America. It examines whether the additional intercontinental link’s costs could be offset by time-zone price differences and electricity trading.

Appendix B. Transmission Costs for a Wind Farm in Greenland

  • The analysis assumes a feasible 3 GW wind farm on Greenland’s eastern shore, routed through Iceland and the Faroe Islands to North UK, with an additional line assessed to North America.The overhead-line cost assumption is €600 million per 1,000 km; cables and overhead lines are assumed to have 3,000 MW capacity, with a 40% offshore-wind capacity factor.Source: Appendix B · pp. 11–12
  • Adding a North America transmission path raises delivery costs from €0.014–€0.019/kWh to €0.029–€0.038/kWh, while the assumed time-zone price advantage could increase revenues by 33%.The 33% estimate assumes wind output is uncorrelated with time of day and off-peak prices are half of peak prices; the case study’s revenue increase is 31% after accounting for higher losses.Source: Appendix B · p. 12
  • Using spare interconnector capacity for electricity trade could deliver 19,554 GWh/year at transmission costs of €0.014–€0.0185/kWh.The line can accommodate an additional 10,095 GWh/year beyond the 4,822 GWh/year delivered to the UK and 4,637 GWh/year to North America as wind power.Source: Appendix B · p. 12
  • The authors characterize both cost assessments as rough estimates requiring more detailed analysis of costs, electricity-price projections and volatility, and landscape and seabed terrain.Source: Appendix B · p. 12

Appendix C. Maps

Appendix C presents maps of wind potential, Earth elevation, and solar potential used to inform renewable-energy siting. The text highlights offshore wind regions and tropical and desert solar potential, while noting that site-level energy output needs more detailed analysis.

Appendix C. Maps

  • Offshore areas generally have higher average wind speeds than land, with the North Atlantic, Pacific, and a belt off Antarctica showing the highest average speeds.The map depicts wind speed 50 m above the Earth’s surface.Source: Appendix C · p. 12, Figure C.2 · p. 12
  • The Earth elevation map can be compared with the wind map to identify regions where sea depths might permit offshore wind farms.Source: Appendix C · p. 12, Figure C.3 · p. 12
  • Tropical areas have the highest solar irradiation, and deserts including the Sahara, Mojave, and Thar show potential for concentrated solar thermal or large-scale solar PV.The text says more detailed analysis is needed to quantify actual electricity output at individual sites, including turbine rated speed for wind sites.Source: Appendix C · p. 12, Figure C.4 · p. 13
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