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9 -11 May 2017 Addis A
babaW
orld Hydropow
er Congress Better hydro
9–11 May 2017Addis Ababa
Briefing materialRenewable Energy Storage
Jiang XiaobingChina Gezhouba Group Corporation
16:30, 10 May 2017
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Contribution of Development of Renewable Energy
Technology to Environmental Improvement
JIANG Xiaobing
China Gezhouba Group Corporation
Abstract
This paper analyzes current environmental conditions and governmental policies of
China, and mainly introduces contribution of the Gezhouba Group to environmental
improvement with renewable energy technology development.
1. Environmental crisis caused by unreasonable energy consumption structure
in China
1.1 Current environmental status of China
According to statistics published in the 2015 environmental report by the Chinese
Ministry of Environmental Protection, 73 of 338 cities above prefecture-level in
China were complying with national ambient air quality standards, accounting for
21.6%; and 265 cities were non-compliant, accounting for 78.4%.
The average conforming days of the 338 cities above prefecture-level account for
76.7%; the non-conforming days account for 23.3%; of which, the mild contamination
days account for 15.9%; middle level pollution days account for 4.2%; heavy
pollution days account for 2.5% and severe pollution days account for 0.7%.
Beijing-Tianjin-Hebei and its surrounding regions are where the most severe air
pollution frequently occurs in China. In 2015, 70 cities in this region recorded 1710
times of heavy or more severe pollution in total, accounting for 44.1% of the whole
country.
1.2 Cause analysis of environmental crisis in China
Irrational energy consumption structure is fundamental cause of the current
environmental crisis in China. The air pollution sources consist mainly of: industrial
pollution sources (e.g., industrial production process, industrial fuel combustion);
agricultural pollution sources (e.g., agricultural fuels, organic pesticides); domestic
pollution sources (e.g., household cooking, domestic heating, waste incineration);
traffic pollution sources (e.g., auto tail gas emission); and fugitive dust. Coal remains
the main energy source in China, however the multipurpose utilization rate of it is not
high due to low mechanization. According to statistics, 70% of smoke dust, 90% of
SO2, 67% of NOx and 70% of CO2 emission come from coal.
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2. Countermeasures of government for environmental crisis
2.1 Energy development strategy
On June 13, 2014, General Secretary Xi Jinping clearly puts forth the strategic
thinking of “4 reforms and 1 cooperation” for secure development of energy in China
in the central finance and economics leadership team 6th session: that is, to promote
reforms in energy consumption; suppress irrational energy consumption; promote
energy supply reform; establish diversified supply system; promote energy
technology reform; drive industrial upgrading; promote energy system reform; open
energy development fast lane; strengthen all-round international cooperation and
realize energy security under open conditions.
2.2 The State “13th Five-Year Plan”
In terms of hydropower, make overall planning of hydropower development and
ecological protection; give priority to ecology; scientifically develop southwest
hydropower resource by attaching importance to leading hydropower station
construction in major river basins. Keep impelling wind power and PV power
development; actively support photo-thermal power. Focus on coastal nuclear power
belt and construct independent nuclear demonstration works and projects safely.
Accelerate development of biomass energy and geothermal energy; proactively
develop coastal tidal energy resource. Perfect supportive policies for wind energy,
solar energy and biomass energy. Optimize national comprehensive energy base and
vigorously propel clean and efficient utilization of coal. Proactively develop natural
gas, CBM and shale oil (gas). Promote upgrading of oil refining industry. And issue a
series of significant documents of The 13th Five-Year Plan for Energy, The 13th
Five-Year Plan for Renewable Energies and The 13th Five-Year Plan for Coal
Industry Development successively.
3. Profile of China Gezhouba Group Corporation (CGGC)
China Gezhouba (Group) Corporation is named for constructing the first dam of
Yangtze River-Gezhouba project and has become a internationally competitive
transnational Group integrating investment, construction, environmental protection,
real estate, cement, civil explosives, equipment manufacture and finance into a whole
over 40 years of development. CGGC is one of the most competitive listed companies.
It ranks top 70th among China’ top 500 enterprises of 2016 in Fortune; and it ranks
45th and 31rd among global “250 International Contractors” and “250 Global
Contractors” in 2016 issued by ENR.
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4. Work of CGGC in renewable energy development
With unremitting efforts of Gezhouba people, it provides one-stop solutions for fuel
gas distributed energy system, compressed air storage system, fused salt thermal
storage system, CO2 power generation, and high proportion renewable energy system
with energy internet as the core and based on diversified energy demands of
customers, covering project investment and financing, design, consulting, power
generator supply, EPC project and project operation & maintenance.
4.1 Fuel gas distributed energy system
(1) Concept and characteristics
“Distributed energy” refers to high efficient combined cold, heat and power supply
system distributed and installed at the user’s end. The system may generate power at
or nearby the consumption place; the waste energy produced by power generation is
used efficiently to produce heat and power and to realize comprehensive utilization.
Characteristics: small energy loss, less pollution, flexible operation, and economically
efficient
The natural gas distributed energy takes natural gas as the fuel to realize energy
cascaded utilization and directly meet varied demands of users.
(2) Application value
It can be applied in gas engine distributed power station, gas turbine power station,
and combined cold, heat & power supply and has the following application values:
Fig. 1: Fuel Gas Distributed Energy
Fig. 2: Conventional Supply Mode
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Safe: Supply power safely and reduce dependence on centralized energy
supply.
Energy saving: save energy by 40% and reduce emission by 60% compared
with conventional sources of energy.
Efficient: realize cascaded utilization of energy and improve energy efficiency
by 30%.
Peak load shifting: realize balanced utilization of energy.
Economical: save 20% operating cost.
Fig. 3: Comparison between CHP and Conventional
4.2 Compressed air energy storage technology
(1) Concept and characteristics
Energy storage is the process of storing energy by medium or equipment and
releasing it in use. CGGC cooperates with Chinese Academy of Sciences in
developing the advanced supercritical compressed air energy storage system, which
gets rid of scientific problems of dependence of conventional compressed air energy
storage system on large air reservoir and fossil fuels, large loss and low efficiency,
and is the domestically largest and internationally advanced compressed air energy
storage system.
Characteristics: low cost, long service life, high efficiency, unlimited by geographical
conditions, e-friendly and safe.
Heat power combined supply
Conventional supply
4KWH 4KWH
Electricity electricity Market
electricity
heat heat Natural
gas 1m3
Natural gas
Distributed energy system Boiler
0.1ton hot water
0.1ton hot water 0.55m3
Cost: 1m3 natural gas=2.43yuan
cost:
4 KWH=4*0.95=3.8 yuan
0.55 m3 natural gas=1.34 yuan
total:5.14 yuan
Customer needs:4KWH, 0.1 ton hot
water
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Fig. 4: Schematic Diagram of Advanced Compressed Air Energy Storage System
(2) Application value-promote energy transformation
1. Realize large scale access of renewable energy
Realize smooth fluctuation of renewable energy, trace scheduling output and
peak/frequency regulation. Enable renewable energy power generation stable and
controllable. Meet large scale access and grid-connection demand of renewable
energy power.
2. Work as load balancing device and backup power of regional energy system
The regional power supply system has higher load fluctuation rate and fault rate;
connection of power energy storage can be used as backup power and load balancing
device.
3. Improve power generation and transmission efficiency, safety and economical
efficiency of conventional energy sources
Currently, the power generation total load coefficient of conventional coal fired power
generator units and power grid load utilization coefficient in China are low, no more
than 55%. The energy storage system can be used to improve them to be more than
80%, remarkably improving actual operating efficiency of thermal power generating
units and enhancing power transmission capacity of power grid.
Cool storage heat exchanger
Expander 1 Expander 2
temperature generator
high
Normal
low
Low temperature pump
Throttle valve
Low temperature storage tank
Waste heat
Heat storage/heat exchanger
Compressor 1
Air Air
Compressor 2
pollutant
motor
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4. Prominent energy saving and emission reduction effect
Take 50MW wind farm for example, if 10MW compressed air energy storage system
is equipped, it is predicted that 1000-1500 wind power on-grid hours can be increased
each year. This not only increase equipment utilization rate of wind power enterprises
but also is equal to reduction of 13600t carbon dust, 49800t CO2, 1500kg SO2 and
750kg NOx each year.
Fig. 5: Comprehensive Experimental Platform of 1.5MW Advanced Compressed Air
Energy Storage
Fig. 6: Bijie 10MW Demonstration Project
Wide load compressor
The high load turbine Auxiliary equipment Cold/heat storage/heat
exchanger
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4.3 Fused salt thermal storage technology
(1) Concept and characteristics
Make use of waste wind, light or off-peak power and realize all-day heating by fused
salt heat storage. It is a kind of green heat supply technology without coal or gas
firing. It can realize local consumption of waste wind/light and power peak load
shifting.
Fig. 7: Technical Principle Diagram of Fused Salt Thermal Storage
Characteristics: fused salt is molten state liquid of salt, and its operating pipe pressure
is low as a kind of high performance heat transmission and storage medium.
Compared with other media, the high temperature stability is high and steam pressure
is low, featuring high safety, low viscosity and non-corrosiveness. It is less
demanding on pipes, valves, tanks and heat exchangers.
(2) Promotion and application conditions
Fused salt heat storage is the technology clearly supported and promoted by national
policies including national air pollution prevention action plan, national renewable
energy consumption, and power peak load shifting. It can be widely used in
residential parks for winter heating, industrial heat supply in industrial parks or plants
and photo-thermal power generation field.
1. Winter heating in residential areas
Green heating by fused salt energy storage represents a new reform of heat supply and
heating mode and lays a solid foundation for green development. This technology
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may reduce haze substantially, and improve power energy utilization rate. It is low
carbon and energy saving, and benefits the nation and the people.
Fig. 8: Storage Heat Application in Residential Areas
2. Industrial heat supply in industrial parks/plants
Fused salt heat storage, a heat storage system, makes use of waste wind, waste
photoelectricity or off-peak power to realize energy storage and then supply it to the
production process in the form of steam or hot water to realize peak load shifting or
consumption of waste power. It replaces the original gas boiler or electric boiler, and
can save cost remarkably. It saves energy and reduces consumption, and relieve
burden of enterprises.
Fig. 9: Storage Heat Application in Industrial Park
3. Photo-thermal/waste heat power generation
The fused salt heat and energy storage technology in photo-thermal power generation
may realize 24h uninterrupted power generation by solar energy so that solar energy
utilization may not be hindered by night time or cloudy weather. It enables solar
energy photo-thermal power generation to become a controllable high quality green
power generation mode.
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Fig.10: Heat Storage Principle Diagram of Photo-thermal Power Generation/Waste
Heat Power Generation
4.4 CO2 power generation technology
(1) Technical principles and characteristics
Supercritical CO2 taken as the working medium for power generation is an innovative
technology. The change from steam to supercritical CO2 working medium replaces
mixed circulation with decades of history and organic Rankine cycle with limited
application, and it has the following technical characteristics:
1) The modular design may realize more than one scale system from 200KW to
50MW.
2) Working temperature range of 200 to 540℃.
3) Extremely high efficiency: the efficiency of a small scale system can be up to
more than 30%.
4) Very high economical efficiency: the power generation cost is reduced by
10-25% compared with steam medium while producing the same power. At
the same cost, its power generation capacity is improved by 7-14% compared
with steam medium.
5) Small floor area and small module size
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Fig.11: CO2 power generation technology
(2) Application value
CO2 power generation technology is used in oil & gas field power generation, nuclear
power, photo-thermal power generation, thermal power, and industrial (cement, steel,
chemical, air separation) fields. The large amounts of waste heat are used for
direct-fired power generation to improve power generation efficiency; heat sources
from each field can be used effectively by waste heat power generation to reduce total
cost.
4.5 High proportion renewable energy system
To promote urban energy structure reform, CGGC launches wind, light, gas, storage
and delivery high proportion renewable energy application solutions to provide
powerful guarantee for realization of new energy cities.
CGGC cooperates with Shanxi Province to make advantage of wind and light
resources of Yangqu County in Shanxi to set up the demonstration base with its
multiple energy storage coupling technology, power station peak regulation
technology, intelligent microgrid technology as well as multi-energy
complementation cloud management technology. 50 billion RMB is invested. When
the base is completed, the annual PV power generation volume is 3.6 billion kwh; the
annual wind power generation volume is 1.7 billion kwh, featuring good social and
environmental benefits.
1. Energy production changes from the conventional single fossil energy to
multiple clean energies: construct 5 million KW large scale
wind/light/gas/storage complementary combined cold/hot/power supply
system.
2. Energy management changes from disorder to comprehensive coordinated
management: get hold of wind/light/gas/storage energy coordinated
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dispatching and economical operation management technology; construct the
first comprehensive energy management center in Shanxi, and establish the
energy coordinated dispatching and transaction mechanism.
3. The energy consumption changes from long-distance centralized energy
supply to distributed local consumption: establish 12MW distributed
renewable energy integrated utilization demonstration, realize zero energy
consumption building, PV poverty relief and PV agriculture.
4. Good environmental benefits: reduce carbon dust of 2.4604 million tons of
carbon dust, 9.0185 million tons of CO2, 0.3808 million tons of SO2 and
0.1357 million tons of NOx each year.
Fig. 12: Effect Picture of Intelligent Distributed Energy Management Platform
5. Conclusions
CGGC will keep fulfilling social responsibilities of central enterprises, increase
scientific research, improve scientific research strength, practically enhance integrated
utilization rate of renewable energy, effectively solve environmental crisis and forge
ahead on energy saving and emission reduction road unswervingly.