The very idea of overall energy supply from an environment up to complete self-sufficiency continues to agitate minds of socio-futurologists for creation of the future harmonious society model. However lately these ideas are implemented right in front of our eyes due to development of PV-generation technologies and storm-like penetration of RES in energy segment all over the world.
In rainy enough June, 2017 in Germany 9 days (almost one third of a month!) nuclear power plants and coal CHP-plants were muffled because of substantial overabundance of energy making on solar and wind power-stations (see fig. 1). From the second week of July Germany unplugged a part of NPPs, reducing production of energy on nuclear stations at 26,8%.
For the first 6 months of this year German energy industry 7,22 produced TW of electricity from wind and 5,83 TW of solar electricity, including domestic stations, producing energy on "green" tariff for "public sector".
Fig. 1. Statistics of electricity production in Germany. June 2017. Source: Fraunhofer Institute for Solar Energy Systems (ISE).
In this June internal province of Qinghai in China, where 5,6 million people live, was fully powered on electric energy from RES during a week, greater part of this power capacity was generated by PV-stations.
Large scale changes take place right now also behind the ocean. In the USA, for example, for the first time in history, energy from RES exceeded nuclear power plants generation almost by 20%. A report of Energy Information Administration (EIA) shows, that this tendency will make progress. In March RES share made 21,6% against 20,34% of NPP-generated, in April 2017 this correlation was equal to 22,98% / 19,19%.
Enormous part of total PV-generation is made at private small power plants (SPPs) with less than 100 kW of power and at domestic PV-stations (up to 30 kW). From data of IRENA agency, on the beginning of 2017 share of solar SPPs made near 40%. In June EIA report together with confirmed statistics for April 2017 the extrapolated data on electro-generation growth on small and domestic private solar stations are provided, as if a financial year was closed in April, see fig. 2. Exponential growth of generation on small PV-energy stations became possible not only due to substantial price-cutting on solar panels of all types, but also because of price-cutting on accumulators and invertors. This equipment allows to build a fully energy independent residential space.
Fig. 2. Extrapolated data on the growth of generation at small SES (May 2013 - April 2014, 15, 16, 17). According to: IEA Electric Power report, Release Date: June 23, 2017.
Against the backdrop of rapid prices reduction on energy storage systems of all types for PV-stations, a phenomenon developed, which was named "escape from network" (grid defection), describing desire of small producers of PV-energy to consume/purchase as little external energy as possible or even to abandon purchasing electricity from external networks completely and only to sell generation surpluses into general network. So to say, to provide some kind of "natural power economy". It is necessary to acknowledge that powerful global development of electric cars became the driver of such prices reduction, including projects on "electro-refuelling" on the base of local "mini-grid" PV-isles.
McKinsey Global Institute analytical company in June 2017 reported about the results of a special research about determination of break-even point of power supply using fully autonomous SPPs with the cost of electric power from a general network.
McKinsey Global Institute company built a generalized model for determination of break-even point for different types of accommodations and public buildings (single- and multistorey schools, office centers, hotels), equipped with PV-facilities. Using both state and private sources, McKinsey received data for six different regions, taking into account more than 1000 different profiles of power load, degrees of "connectedness" of a building to the general network, dozens of battery types (including Li - ion, leaden-acid, alkaline and other accumulators), hundreds of tariff plans and tables of prices on electric power. The model of McKinsey Global Institute also took into account other factors of solar SPPs application for an residential accommodation, such as energy deficit peaks smoothing, frequency stabilization services, change or improvement of control of generation from RES in the scale of a local network.
It turned out, that an energy self-sufficiency or maximization of solar energy use is economically not by far all building types. Only 58% of buildings with autonomous (standalone) power supply (which cover 71% of general demand on electric power) can be theoretically break-even. Thus the range of optimal work from batteries for self-sufficient buildings makes no less than 31 kW·h and up to 170 kW·h. And the more is power capacity of the storage system, the more profitable complete transition to RES will appear.
McKinsey company also forecasted, when complete or partial "escape from a network" will happen, taking into account prices reduction on storage systems. Calculations, taking into account self-weighted cost of own electro-generation and price advance on energy from a general network, showed that at present rates of prices reduction on energy storage systems, the break-even point for "100 % grid defection" (scenario of complete "escape from a network") will come already in 2030.
Fig. 3. When there is a "flight from the network" - 100% autonomy (left), self-sufficiency PV-energy by 90% (right). Source: McKinsey Global Institute, «Battery storage: The next disruptive technology in the power sector», июнь 2017.
At a scenario, when 90% of consumption is covered by own generation, and 10% is acquired from a general grid ("partial escape from a network"), the point of equilibrium will come already in 2020-22, see fig. 3.
According to analytical report of Morgan Stanley bank, published at the beginning of July 2017, energy from RES will become the cheapest type of energy yet before 2020. "Point of inflation" in electro-generation industry will happen already in 3 years: "Numerous key markets achieved the inflection point recently, where RES already became the cheapest form of new energy". "This dynamics, which we are monitoring now, spreads virtually to all countries, and it will "cover" them to 2020".
Current prices on Li-ion batteries went down on 30% compared with 2014. European energy company Enel, using IRENA data (see fig. 4), forecasts that prices of storage-battery systems will decline yet on 30% to 2021.
Fig. 4. Estimation and forecast of prices for Li-ion batteries of different types until 2020. Source: International Renewable Energy Agency (IRENA), Battery storage report, 2015.
This confidence is based on large-scale business plans of global corporations. Тесла is by far not a solitary one company, making accumulators for domestic systems of energy storage. Such companies as BYD, Foxconn, LG Chem, Samsung and others intensively invest in the production of Li-ion batteries all over the world. Financial Times reports that yet minimum 13 factories, comparable with Tesla Gigafactory, are either already built or ready to be constructed at full speed.
Elon Musk announced just a week ago, that after Gigafactory-1 will achieve its projected power( approximately in 2020), Tesla company plans to open 2 or 3 large Gigafactory plants in the USA, where accumulators and electric cars will be produced. News appeared at the end of June, that Elon Musk’s company made an agreement on building of another batteries production facility in Shanghai, China.
To compete Tesla (and to produce 2-3 million electic cars every year), Volkswagen business concern plans to build about 40 plants on accumulators production, similar to Gigafactory-1.
Beginning of construction works on European storage-battery plants is expected in two years in Finland and Sweden. Samsung promises to build a Gigafactory in Hungary.
Rapid price decline on accumulators in Europe and China was mentioned in research of accumulator battery storage systems, conducted by McKinsey Global Institute company. On European and Chinese markets price on storage batteries fell down approximately on 80% from 2010 to 2016, from approximately 1000 $/kW*h to approximately 227 $/kW*h (see fig. 5). It is expected that to 2020 costs of accumulator battery blocks will be within 100 to 200 $/kW*h price range, and to 2030 it will drop below 100 $/kW*h..
Fig. 5. The forecast of prices of Li-ion batteries up to 2030 (according to the McKinsey Global Institute on the basis of statisticsIHS, Bloomberg New Energy Finance, JATO, National Development and Reform Commission of China).
McKinsey Global Institute named its research of pre-conditions for mass "escape from a network" as "Accumulators: next destructive technology in energy", considering that "green" revolution, starting from reduction of prices on technologies of RES generation (for example, PV-panels), will not stop thereon. Its consequences can fully prang the formed infrastructure of energy supply.
Nowadays the complete disconnecting from centralized system of power supply is economicalle unprofitable yet. However 80%-90% self-sustainment with the use of accumulators and general network access as security option for uninterruptable power supply seems to be a fully tangible prospect. At the current rates of prime price decline "escape from a network" can "make sense on some markets even before somebody expects", as McKinsey authors believe.
"Solar isolationism", especially partial, is not so inoffensive for present energy industry. Besides generation of power at the level of consumption it is necessary to retain stable frequency of current in all branches of a network. While systems of electric power production from RES can not independently provide stable power generation capacity because of inherent daily and seasonal unevenness. Wind stations and solar power plants are also very dependable on weather changes.
Operational algorithms of modern charge controllers allow to redistribute uneven (peak) generation from wind and PV-stations to own energy supply of households (see fig. 6). This, from one side, can lift up the degree of material self-sufficiency of househols on two thirds, and from other side it will decrease the unevenness of "upcast" of energy surpluses into general network.
РFig. 6. Optimized energy storage systems for the grid, working on a "green tariff", to increase the level of its own power supply. According to IRENA and Fraunhofer ISE, Battery storage report, 2015.
Optimization of PV-energy self-consumption may to take off the main contradiction which is obvious at the spontaneous increase of SPPs number, namely unevenness of energy supply into general network, all without considerable building of large accumulator battery stations and "rapid" compensative powers of national and regional scale.
Development of generation from RES requires changes and updates for power supply infrastructure. The revision of present policy of centralized power supply and electric systems structure is needed for the sake of providing conditions for distributed electro-generation from RES, especially for PV-stations. The degree of self-sufficiency and "isolationism" of nowadys consumers of retail electric power will only increase otherwise. In these conditions consumers, whose own electro-generation will be unjustified economically (and according to McKinsey calculations this share is 42%), for differents reasons will happen to be in difficult situation.
"Large" energy companies should not necessary consider local storage systems and increase of consumers’ self-sufficiency (for those who possess an SPP), as a threat to their present-day, often monopolistic, profits. Commenting on the situation, Morgan Stanley bank recommends to send costs, saved due to your own generation, for example, into communal sector, exactly on development and modernization of local energy networks infrastructure for their better co-ordination with regional networks.
It is necessary to intentionally stimulate the access of small producers of electric power to energy networks, including reduced connection payments for SPPs, working on "green" tariff. Then the law of large numbers will work: the enormous amount of small electric power producers will be able to smooth out unevennesses of both generation and consumption