In recent years, the rural energy consumption in China keeps increasing because
of the economic and social development. In 2009, 366.5 Mtoe of energy were consumed
in rural China (Zhu, 2011), which contributed 25.6%
of national energy consumption and 4.41% of global energy consumption (NBSC,
Constrained by the economic level, the rural residential energy consumption
is mainly for basic need in China. In building thermal design zoning, almost
the whole northern China is in cold zone and severe cold zone. Residents there
need to heat their room in winter. Cooking and heating are the essential energy-using
activities for the living in northern China and contributes most of the energy
consumed in northern rural households.
Both cooking and heating use heat that released by burning fuels. Because of
the efficiencies of energy-using appliances, the amount of heat received by
the consumers is always less than the total energy amount contained in the energy
resources. There are various patterns of cooking and heating in rural area,
but the thermal efficiencies are lower than that in urban area. In order to
improve the energy efficiency and relieve the pressure of fossil energy supplement,
it is urgent to develop rural energy planning based on renewable energy technologies.
Both the data of consumed energy resources and received energy amount are requested
for rural energy planning, in order to determine the system scale and feasibility.
As the main energy-using activities of rural households in northern China, cooking
and heating should be paid great attention and studied in both terms of supply
Most of the existing research on rural energy issues in northern China took
cooking and heating as an integrated part of residential energy-using. By focused
on not only the consumed energy resources but also the distribution of energy
resources in cooking and heating, a few researchers obtained detailed results
on energy structures of some rural areas in northern China. Ning
et al. (2012) investigated and analyzed the framework of energy consumption
in rural households throughout northeastern China. They found that straw and
firewood, which together accounted for 68.8~78.3% of all energy consumption,
were energetic categories that most largely used in residences, besides, cooking
and heating accounted for 64.0~95.4% of all residential energy consumption.
Zhou et al. (2007) analyzed the evolvement of
rural household energy consumption structure in a typical comparatively well-off
countryside in a County of Shandong province. They concluded that coal consumption
increased and dominated in all energy sources and energy consumption of cooking
and heating became nearly equivalent while cooking energy consumption dominated
in the past. Li (2007) defined the energy-ecology-economy
system and took rural household in loess hilly region in Gansu province
as the study area. He deeply analyzed the potential of energy resource development,
such as household energy structure, impact on local environment, economic cost
of energy consumption, etc. Finally he pointed out the way of optimizing the
energy-ecology-economy system in that region. Though the achievements above
have made some progress while other studies were solely on the amount of energy
consumption, they paid no attention to the effective heat of cooking and heating
demand. Besides, the scales of them are limited in some particular areas.
In this study, based on the data from surveys and statistics, the supply and
demand of cooking and heating energy of rural households in northern China are
studied through the calculation of annual indices such as consumed energy, effective
heat, integrated efficiency, etc. The conclusion provides reference information
for rational planning and utilization of rural energy.
MATERIALS AND METHODS
Rural energy data of different regions in northern China are collected from
surveys and statistics. The units of fuels are converted to a unit of energy.
Then the amounts of effective heat received by users are calculated according
to energy efficiencies of appliances. Finally a series of rural energy indices
in northern China can be derived, some of which are compared to those of urban
Calculating methods of energy supply and demand: This study takes consumed
energy as the main index for energy supply and effective heat for energy demand.
The consumed energy is defined as the total amount of energy contained in the
consumed resources. The effective heat is defined as the amount of heat received
by consumers, which equals to the amount of heat delivered to consumers by appliances.
Supposing that the consumption amount of a type of energy resource is M [t],
v is the corresponding calorific value [GJ/t], thus the consumed energy (E)
Taking into account the thermal efficiency of the appliance corresponding to
this type of energy (η), then the effective heat (H) is [GJ]:
Supposing n types of energy resources are consumed, the integrated efficiency
(ηn) is defined as the ratio of total effective heat to total
consumed energy of the n types of energy resources. ηn is calculated
Basic data: For cooking and heating in rural areas in northern China,
most residents combust fuels in their own houses and use the released heat.
The energy-using appliances and energy resources that most commonly used for
cooking and heating by rural households in northern China are selected in the
The calorific values of energy resources and thermal efficiencies of energy-using
appliances are listed in Table 1 and 2.
Currently, the consumptions of firewood and crop residue are not included in
national statistics of China. 2012 Annual Report on China Building Energy Efficiency,
written by (Building Energy Research Center of Tsinghua University,
2012) contains surveys on rural residential energy consumption in all 15
provincial administrative of northern China. The detailed data from the surveys,
as an example shown in Table 3, are taken as the basic energy
consumption data for the calculation of energy indices of rural cooking and
heating. Other basic data for the study are taken from related statistical yearbooks.
||Calorific values of energy resources for rural cooking and
heating in Northern China (NBSC, 2012)
||Thermal efficiencies of energy-using appliances for rural
cooking and heating in Northern China
||Annual energy consumption data in cooking and heating of rural
households in Beijing [104t]
RESULTS AND DISCUSSION
General annual characteristics: In northern China, the annual consumed
energy of rural cooking and heating is larger than urban residential consumed
energy, regardless of the total or per capita amount Table 4.
Since the residential consumed energy includes not only cooking and heating
but also lighting, entertainment, etc., which attribute significant proportions,
the consumed energy of cooking and heating of urban households is significantly
less than that of rural households. The total and per capita consumed energy
of rural cooking and heating contributed by fossil energy are also shown in
Table 4. The total fossil consumed energy of rural cooking
and heating is 1.65 times of the urban residential consumed energy (3.40/2.06
= 1.65), but the ratio of per capita amount drops to 1.11 because of the larger
rural population (9.12/8.21 = 1.11). That means in northern China, residential
consumption in rural area contributes higher pressure on regional supply of
fossil energy than that in urban area.
In rural area of northern China, the consumed energy of heating is 1.74 times
of that of cooking (Table 5, 3.04/1.75 = 1.74) but the ratio
of effective heat rises to 7.26 because of the higher integrated efficiency
of heating (1.67/0.23 = 7.26). Therefore, a conclusion can be drawn that heating
is the primary energy demand of rural households in northern China.
Fossil energy accounts for about 71% of total consumed energy and more than
93% of total effective heat of rural cooking and heating in northern China (Table
6, 3.40/4.79 = 70.98%, 1.77/1.90 = 93.16%). The two ratios show the great
dependence on fossil energy of northern rural households. However, the integrated
efficiency of renewable energy is significantly low while the integrated efficiency
of fossil energy needs to be improved as well.
Annual per capita characteristics by region: The annual per capita consumed
energy of rural cooking and heating in Beijing, Heilongjiang, Shanxi, Xinjiang
and Liaoning are larger than that in other northern regions (Fig.
1a). Henan has the minimum annual per capita consumed energy both of rural
heating and total and its the
only region in which the annual per capita consumed energy of rural heating
is less than that of rural cooking. In every region except for Henan, the ratio
of annual per capita consumed energy of rural heating in total is about 60~70%
Comparing to the study by Ning et al. (2012),
in the northeastern region (Liaoning, Jilin and Heilongjiang), the total rural
annual per capita consumed energy in this study doesnt have considerable
difference, but the amounts of cooking in 3 provinces are all relatively low
while those of heating are all relatively high (Table 7).
||Consumed energy of rural cooking and heating and urban residential
consumed energy in Northern China [GJ/a]
|| Energy-using of rural cooking and heating in Northern China
||Fossil/Renewable energy-using of rural cooking and heating
in Northern China
||Comparison of rural annual per capita consumed energy in Northeastern
|L: Liaoning, J: Jilin, H: Heilongjiang
||Annual per capita consumed energy and effective heat of rural
cooking and heating, (a) Consumed energy and (b) Effective heat
This may be caused by different classification of the consumed energy for winter
cooking: in order to save heating cost, if not extremely cold, some households
use the heat from cooking energy for space heating.
In Beijing, Shanxi and Xinjiang, the annual per capita effective heat of whether
rural heating or total is significantly larger than that in other northern regions
while these two indices in Henan are both the least (Fig. 1b).
Beijing, Shanxi, Liaoning, Heilongjiang and Xinjiang have significantly larger
annual per capita effective heat of rural cooking. In every northern region,
80~95% of the rural annual per capita effective heat is of heating (Fig.
2b), thus indicating that rural households in all northern regions always
demand much more heat yearly for heating than for cooking.
In Beijing, Shanxi and Xinjiang, the fossil annual per capita consumed energy
of both rural cooking and heating are significantly larger than those in other
northern regions. In Liaoning, Jilin and Tianjin, the fossil annual per capita
consumed energy of rural cooking are significantly less than that in others
(Fig. 3). In every region except Henan, 60~90% of the rural
fossil annual per capita consumed energy is for heating (Fig.
||Distribution ratio of cooking and heating in rural annual
per capita consumed energy and effective heat, (a) Consumed energy and (b)
Considering that all fossil energies in rural area are commercial energies,
it can be inferred that for most rural households in northern China, energy
costs are mostly spent on heating.
Among the northern regions, the ratios of rural fossil annual per capita consumed
energy in cooking vary more greatly than that in heating (Fig.
5). In northeastern regions (Liaoning, Jilin and Heilongjiang), both the
two ratios are less than that in others, thus indicating that renewable energy
(mainly crop residue) still plays an important role in rural residential energy-using
in northeastern China. This finding can be supported by the previous study by
Ning et al. (2012), described in BRIEF introduction
of this study. At the other side, both the two ratios in Xinjiang, Beijing and
Shanxi are at higher levels.
The integrated efficiencies of both fossil and total energy in every northern
region are illustrated in Fig. 6. It can be seen that the
northeastern regions (Liaoning, Jilin and Heilongjiang) have higher fossil energy
integrated efficiencies but lower total energy integrated efficiencies.
||Fossil annual per capita consumed energy of rural cooking
||Distribution ratio of cooking and heating in rural fossil
annual per capita consumed energy
||Distribution ratio of fossil and renewable energies in rural
cooking and heating annual per capita consumed energy, (a) Cooking and (b)
||Integrated efficiencies of both fossil and total energy
Related to the thermal efficiencies in Table 1, it can be
inferred that in northeastern rural households, biomass stoves are commonly
used for cooking while coal stoves are commonly used for heating.
Comparing to the study before, this study takes all the 15 northern regions
of China as the study area and paid attention to the effective heat of cooking
and heating demand. Through the calculation and analysis of consumed energy,
effective heat and integrated efficiency of rural cooking and heating, some
conclusions about rural energy supply and demand in northern China can be drawn
||Northern rural households depend greatly on fossil energy
in cooking and heating. Residential consumption in northern rural area contributes
higher pressure on regional supply of fossil energy than that in northern
||Northern rural households always demand much more heat yearly for heating
than for cooking and energy costs in most rural households are spent on
||The efficiencies of both renewable and fossil energy need to be improved
||For many indices, Beijing, Xinjiang and Shanxi are at the highest level
than other northern regions. These indices include annual per capita consumed
energy, effective heat, fossil consumed energy and ratio of fossil consumed
||For rural households in northeastern regions (Liaoning, Jilin and Heilongjiang),
renewable energy (mainly crop residue) plays an important role in energy-using
and is mostly consumed for cooking, while coal is mostly for heating