An innovation idea for energy transition towards sustainable and resilient societies: Global energy interconnection

Along with global economy burst and gradual transition of its development pattern, the incompatibility between natural environment and energy consumption rises sharply.In September 26th, 2015, president Xi Jinping put forward the proposal about exploring the establishment of Global Energy Interconnection (hereafter GEI) and promoting the satisfaction of global electricity demands in a green and clean manner, which intends to cope with global climate change and realize energy sustainable development by improving the cleanness and performing transition of energy structure [1,2].

In such context, the establishment of Global Energy Interconnection Development and Cooperation Organization (hereafter GEIDCO) officially realized in March 29th, 2016, and became the first international organization initiated by China in energy field. Since its establishment, the innovative idea of GEI proposed by GEIDCO based on the inspiration of global view of energy and internet thinking has been widely praised and fully recognized [3,4].

However, there are also doubts and even misunderstandings against the idea due to the differences of standpoints and views of energy development, and one of the mainstream viewpoints simply regards GEI as a link of worldwide power grids.

In fact, other than grid linking, it contains a series of development ideas sand methodology innovations, which remarkably differ from conventional ideas and modes of energy industrial system, and brew profound thinking about clean and green development and even greater commercial opportunities.

It is the objective of this article to summarize and clarify the essence of such innovations, and relevant discussion is performed as well.

1 Methodology Innovation of the Idea

Transition from conventional fossil energy to renewable clean energy and the use of electricity as the main carrier of final energy consumption have basically become a consensus.

Brand new development patterns require brand new ideas as well. Its core standpoint of global view of energy is to study and solve energy issues from global, historical and open perspectives.

The conception and idea of GEI are based on such a view and internet think, which could be generalized as platformed, nonlinear, decentralized or multi-centralized connectivity. Methodology innovation of the idea of GEI can be summarized as following.

1.1 Green & Clean

It is the original intention and fundamental meaning for the establishment of GEI to realize clean and lowcarbon energy utilization, which also involves energy development, transportation, distribution and so on.

Supply was the top priority back in time of energy shortage. Its quality, security and negative environmental affects was overlooked for a long while. In association with extensive utilization of energy, severe environmental issues exposed in many emerging economies, including China,which is obviously against current background of energy transition and upgrading.

Rightfully presented as a better alternative to coal, gasfired generation loses some of its attractiveness when the fuel supply chain is fully taken into account, with upstream flares and pipelines leaks. Moreover, one should remind that even without any emissions, possible using of CCS,electricity generated by fire – the burning of fossil fuels –still adds a substantial amount of heat to the planet’s natural cycle: the conversion of low grade energy such as heat in higher grade like electric power is inherently limited in efficiency. Hence a growing consensus in favor of “nonfire” generated electricity is made, as well as development of electricity-based alternatives wherever it is possible –such as EVs now, and possibly many other energy usages in near future, in transportation or industry sectors.

According to IEA reports, global demand of renewable to total primary energy has increased from 12% in 2000-2010 to 32% in 2010-2016. Complying with such irreversible trend, GEI aimed at laying the foundation platform for clean energy development, allocation and utilization in large-scale, which guarantees the power source clean and low-carbon.

Unlike fossil fuels, the main primary sources of renewable energy – sunshine and wind – resist any notion of ownership: nobody owns them, though the place where they can be harvested often – but not always – belongs to at least a country, if not a person – juristic entity or simple population. In addition to this “property defiant”characteristic, these main primary sources also differ from fossil fuels in that they are neither “transport-able” nor“trade-able” as such, unless they are first converted into electricity.

But In comparison with transportation mode of conventional energy, such as shipping, railway and even pipeline, power grid has its obvious advantages in either energy consumption, land occupation, efficiency and cleanness. At last, as clean energy itself, utilizing electricity would not cause any second pollution.

Finally, if sun and wind based generation will undeniably present some challenges of post-decommission recycling, these will be less pervasive than CO2 emissions or excess heat generation, and still leave some time to prepare and get ready for them – developing different solutions along different business models.

In a manner of speaking, energy interconnection is born for clean and low-carbon energy. It guarantees large-scale development and utilization of clean energy by interconnecting them through electricity, while such development and utilization would also promote the improvement and realization of GEI.

1.2 Balanced & Reciprocal

Reconsideration of energy network from a balanced and reciprocal perspective is the most distinctive innovation towards clean energy development of GEI compared with conventional power grid. In the time that with unfit transportation facilities, most produced energy could only be consumed nearby or transported on limited level.

China for instance, rich regions of energy resources are mostly located in less-developed areas, while southeast areas as the main consumers are relatively poor in energy resources, which causes regional segmentation of energy production and consumption. The ‘west-east natural gas transmission’ and ‘west-east power transmission’ projects implemented afterwards are exactly regional practices of such idea.

Moreover, its regional, seasonal and even diel distribution imbalance and output instability are the disadvantages for renewable power generation. They challenge peak load regulation capacity and stability of most power systems existing if renewable power penetrated heavily together with user demand difference caused fluctuation.

Although pump-up power station and other power storage technologies become gradually mature, yet are still insufficient in dealing with this overall issue, which explains why even in advanced power systems with high proportion of renewable power still cannot cast off nuclear or coal power as its base load.

However, this problem seems solvable if considered from GEI balanced and reciprocal perspective. Renewable energy distribution and user demand of power are relatively stable or can be managed if standing on higher dimensions,like a continent or even the whole world.

Indeed the sun is always shining somewhere, as one could say, and it is unlikely that wind does not blow anywhere at any given time! More simply, extended renewable generation bases on a sizeable geographical perimeter could well allow for a kind of “partial selfbalancing” aggregate generation, as it starts to be seen with wind in the EU – this contribution to balancing being enabled by cross-border grid connections.

Conversely, the same connections could allow fossil fuel fired generation to contribute to grid-balancing in extended perimeters, thus offering new prospects to power plants that could otherwise find less opportunities to generate and maintain their capacity factor. Whereas considerable potential renewable generation bases, distant from load centers, could find their justification, with accesses granted to more than one national grid, whatever their sizes.

As the distinctive advantages of GEI, long distance transmission and efficient dispatching could actualize such hypothesis, while with considering its huge capacity, GEI itself can be treated as a buffer or storage in dealing with load fluctuation.

1.3 Efficient & Intelligent

It is broad and sophisticated UHV grid as the basic framework of GEI, while power dispatching and allocation in precise and rational manner is its final goal.

Unlike generation-transmission-consumption one way,linear connection in conventional power system, GEI intends to break the up-to-down pattern and build efficient,intelligent and multi-way energy networks for information and power flow and achieve real “interconnection”.

On the side of generation, it involves relatively stable sources, like nuclear, hydro-, conventional thermal power, and unstable wind, photovoltaic power, and other distributed generation. By introducing intelligent technologies and devices, such as Internet of Things,Big data and embedded information processors, it will be feasible for GEI to practice information analysis and decision-making, whether to transport or store power, or adjust operating condition of plants.

On the side of consumption, it involves intelligent factories, buildings, residences and e-vehicles, together with distributed generation, like self-use solar panels,small windworks and so on. Instead of just being takers,all of these would be able to join in the operation of power systems by deciding whether or when to connect to the grid according to their own demand and utility.

This is where the “internet style thinking” comes into play. Such global interconnections will exponentially multiply options at the level of sizeable generation sourcing and UHV transmission, whereas distributed generation and local smart grids ensure the same perspective at downstream level. The volume of information and the different levels of optimization clearly call for big data style management, with non-linear, multidirectional power flows and multi-platformed decision making steps.

In respect of that, other than optimal energy allocation,GEI would also make efforts for guiding and fostering rational patterns for energy consumption through demand responding and other feedback mechanisms. Such flexible,intelligent regional power systems and matched trading markets have emerged in west Europe and Nordic area,which proved the feasibility of GEI.

1.4 Vitality & Business opportunity

Striving to develop a brand new and dynamic business model is another innovation of GEI.

As a long-term, systematic project, it would be exanimate, unsustainable and against its original intention if its establishment only relies on government input or subsidy. According to economic views and exactly as the burst of internet industry, it is quite positive that broader boundary, fluent information communication and lower transaction cost brews vigorous market and huge business opportunities.

By analogy with establishment and evolution process of existing oil and natural gas trading hubs, it seems promising that either as real or financialized product, electricity could be vibrant trading object based on GEI platform brewed regional, even global power market.

Such development could even become “selfsustainable”, in that it may create conditions allowing renewable generation projects to find their financial justification. As such, the development of markets for grid ancillary services and the monetization of such services seem to offer some incentives to offshore –but not only – wind projects in the interconnected EU electricity market.

Moreover, such markets are now partially served by cross-border connectors – with even some sub-sea connectors in the EU being conceived as dedicated to such ancillary services (Baltic sea) or finding their financial closing thanks to “expressions of interest” gathered from the markets they will connect (English channel).Transmission and connectors projects can become investments in their own rights, not any longer mere byproducts of new generation investment decisions.

In addition, along with gradual maturity of UHV and relevant technologies, facility construction, operation and maintenance costs would decline accordingly, which makes infrastructure investment of GEI more attractive.

2 Practices in ASEAN

In ASEAN, many typical research and practical works related to the ideology of GEI have been done. In terms of power market mechanism, Ref [5] proposes an optimal congestion management approach in a deregulated electricity market using particle swarm optimization with time-varying acceleration coefficients (PSO-TVAC). The optimal congestion management minimizing redispatch cost can be expressed as

where ICg is incremental and decremental cost of generator g.∆ Pg is active power adjustment at bus g.

PSO-TVAC is used to determine the minimum dispatch cost, of which the velocity updating equation could be expressed as

where c1i, c1f, c2i, c2f are the initial and final values of c1,c2; rand1 is the random numbers between 0 and 1, w is the inertia weight.

Ref [6] proposes a transmission pricing based on a combined postage stamp method and sensitivity indices for electricity cross-border trade in the ASEAN Power Grid (APG). The postage stamp pricing is a uniform tariff expected to recover project investments, operation and maintenance costs. The tariff can be calculated as

where UCN is a uniform tariff due to the peak export and import of the year N; is the annual revenue requirement; is the sum of the expected peak export and import amounts from each country; and n indicates the number of member countries. Each country must declare the expected revenue requirement and the forecasted peak exports of the year N from cross-border exchange.

The nodal tariff for node k is

The payments of buyer and seller are calculated as follows.

Where and are the payment of seller and buyer at bus k;and are the exported and imported amounts at bus k.

In Ref [7], a unified transmission pricing based on electricity tracing methodology of cross-border trades among the Association of South East Asian Nations(ASEAN) members is proposed. The use-of-system charges comprise a charge of the transmission capacity usage and a charge of transmission losses in the interconnection system.Loss allocation to loads can be calculated as:

Loss allocation to generators:

Losses Charge of importing/exporting country k:

(a) Payment by the producer in exporting country j:

(b) Payment by the consumer in importing country:

(c) Revenue from transmission losses of TOs:

Simulation results indicate that the proposed method could ensure a recovery of investment costs and concurrent costs of operation and maintenance in an efficient, fair and simple manner.

In terms of clean energy development, Ref [8] proposes a binary particle swarm optimization (BPSO) with timevarying acceleration coefficients (TVAC) for solving optimal placement of wind turbines within a wind farm.The objective is to extract the maximum turbine power output in a minimum investment cost within a wind farm.The problem of optimal placement of wind turbines is given as:

where N = number of wind turbines installed in a wind farm{0<N<100},Sij= position of wind turbines in a wind farm, Sij = 1 for the cell placed by a wind turbine, Sij =0 for none, fk= wind frequency distribution

The position value in each practicle represented by binary defined:

Test results indicate BPSO-TVIW (time-varying inertia weight factor), BPSO-RANDIW (random inertia weight factor) and BPSO-RTVIWAC (random time-varying inertia weight and acceleration coefficients) lead to maximum power extracted in a least investment cost manner.

Ref [9] describes the development of a simulation model for predicting the performance of a solar photovoltaic (PV) system under specified load requirements and prevailing meteoro logical conditions at the site location. This study is aimed at situations where the loads are provided by alternating current (AC) electrical devices.The output current of the PV array consisting of several PV modules can be expressed as:

Where Ip = output current, Il = light generated current per module, Io = reverse saturation current per module,M = number of module strings in parallel, N = number of modules in each series string, V = terminal voltage for module, Rs = diode series resistance per module (ohms),Rsh = diode shunt resistance per module, q = electric charge,k = the Boltzmann constant, and Tp = cell temperature.

When the light-generated current becomes equal to the short-circuit current (Il = Isc), since Rs is very small, the light is concentrated. This model expresses Isc as a function of solar irradiance and temperature.

where P1, P2, P3 = constant coefficients for Isc, Gr =reference solar irradiance, G = solar irradiance, and Tr =reference temperature.

The rate of change of Tp is suggested by

where mCpmodule= effective thermal capacity of the PV module at temperature Tp, Qin = solar energy absorbed by the module, Qrad = radiative heat loss, Qconv = convective heat loss and Qelect = electrical power produced.

The data- flow diagram of the simulation model is shown in Fig.1.

Fig.1 The data- flow diagram of the simulation model

In terms of demand side, Ref [10] selects Thailand as a case study to analyze changes in its energy sector. In the analysis, 2 different scenarios, which are the reference(business as usual) scenario and the disruptive technology scenario, are compared. The reference scenario assumes current Thailand energy plan or Thailand Integrated Energy Blueprint (TIEB) is continued, while the disruptive technology (DTECH) scenario is a projection where exponential growth of potential disruptive technologies—electric vehicle (EV), energy storage, and solar photovoltaic—are introduced to energy sector.

The total energy demand of vehicle stock in transportation sector in a given calendar year can be calculated:

The total stock of each vehicle type and fuel type can be determined as shown in (3):

The vehicle sales estimation models were calculated:

Where ED(t) is total energy demand in year t,Vs tock, i, j (t)is the total stock of vehicle type I, using fuel type j, in year t,VKTs tock, i, j (t) is the stock’s average annual mileage of vehicle type I, using fuel type j, in year t, andFE stock, i, j (t)is the stock’s average fuel economy of vehicle type I, using fuel type j, in year t.Vs ale,i (t) is the number of new vehicle type that sold in year t.ϕi( k ) is the survival rate of vehicle type i with age k,ψi, j(v) is the percentage share of fuel type j within the sales of vehicle type i in year v.Gc ap (t)is the per capita GDP in year t,D econ (t) is the dummy variable for the economic crisis in year t.

The results of this study show that the high penetration of disruptive technologies in DTECH scenario will decrease the greenhouse gas (GHG) emission by 8.9% compared with the TIEB scenario. And if a real-time pricing concept is introduced, it could encourage consumer to charge EVs during an off-peak period. The impact of peak load can be controlled, and it will reduce the need of future power supply.

In terms of policy, Ref [11] assesses all the programmes and projects proposed in the ASEAN Economic Community (AEC) Blueprint and the ASEAN Plan of Action of Energy Cooperation (APAEC) 2010–2015. This paper also creates a scorecard to quantitatively assess the progress.The score for each programme is the average of the scores of its key strategies:

The sector score is aggregated by the programme’s scores:

Where n is the number of strategies under each programme and ϕiis the weight of the ith strategy. The results are shown in Table 1.

Table 1 Scores of Programmes under APAEC 2010-2015

No Programme name Programme weight Score 1 ASEAN Power grid(APG)Physical Infrastructure 0.25 1.38 2 2 Trans-ASEAN Gas Pipeline(TAGP)Physical Infrastructure 0.25 1.81 3 3 Coal and Clean Coal Technology(CCT) 0.1 1.00 4 Energy Efficiency and conservation(EEC) 0.2 1.86 5 Renewable Energy(RE) 0.15 1.53 6 Civilian Nuclear Energy(CNE) 0.05 0.80 7 REPP — —Overall 1 1.59

This study finds that there are significant challenges in energy sector to meet the targets of the AEC in 2015.Progress, in terms of cooperation, being referred to as ’soft infrastructure’ in this paper, has been slower than that of the physical infrastructure. ASEAN energy cooperation is also challenged by factors such as financial constraints, the lack of fiscal arrangements, and the technical and regulatory differences between countries.

From the above analysis, GEI has been put into practice partly, but need to be practiced in an innovative way, to promote the energy transition towards sustainable and resilient societies.

3 Conclusion and Discussion

Given the above, it could be summarized that the core idea of GEI is to establish a Green, Reliable, Intelligent and Dynamic energy GRID globally.

Such a deep holistic transformation of the electric energy system is very far reaching. It calls for a substantial change in the ways of its conception and planning. Energy security, a legitimate concern, too often fringes on Energy Sovereignty – as far as electric power is concerned.Possibly, favoring market style developments will smooth out the uneasiness grown out of a “loss of control” feeling.Market rules and grid operation procedures will need take this into account.

Renewable energy policies remain specifically national because they still in many cases involve subsidies born by taxpayers. Jumping over borders will however allow a much faster and efficient transformation of our world’s electric power systems. It will help avoid the repeat of such geopolitical plays that happened around oil and gas resources: in other words, enabling electric power to reach the same international status as that of more traditional primary energy sources such as fossil fuels.

Stretching the imagination a bit, such global interconnections will enable the necessary infrastructure to one day agreement and call upon primary renewable resources in international areas – distant offshore wind,or wave power for example. Or even, stretching the imagination further, to solar electricity generated in space –someday.

For now, what is worthy to be emphasized is that although the objective is based on power transportation and distribution as elementary mediums, yet the essence of GEI is definitely not as simple as series connection of power grids.

The term ‘global’ indicates the extent of the subject,which is worldwide.

‘Energy’ means that it is not exclusive to electricity only.

Instead of that, fossil and other non-renewable energies are and will be crucially significant to the whole energy system for a very long period. Natural gas and nuclear power, for instance, are even in the rising stage of development. Synergy and complementation among different energy forms, realization of energy clean and electrified transition and substitution would be the core missions for GEI in long term.

At last, ‘interconnection’ indicates that rather than conventional producing-to-consuming linear connection,it intends to achieve interflows and interactions on multiple dimensions within the whole energy system for worldwide optimal allocation through intelligent monitoring,information feedback and market price mechanism.

Furthermore, the innovations mentioned above are interdependent and synergistic logically. To achieve clean and low-carbon energy development is the core mission of GEI, and all characteristics as being capable for long distance transportation, effective dispatching and intelligent interconnection are all designed to serve this objective by offsetting instable output of renewable energy and realizing optimal allocation. Moreover, complete power market with robust trading became possible after all such conditions are satisfied.