Efficient use of energy in small size brewery
Anna Beloborodko, Liga Zogla, Marika Rosa
Institute of energy systems and environment, Riga Technical University, Azenes Str.12-1, Riga,
Latvia, LV-1048
[email protected], [email protected], [email protected]
Corresponding author: Anna Beloborodko, Riga Technical University, Azenes Str.12-1, Riga, Latvia,
LV-1048, Tel: +371 26357568, [email protected]
Abstract
Industrial production is a significant consumer of materials and energy, therefore efficient use
of energy in industrial processes is important to reach the global sustainability targets. This
study examines a small-size brewery in Latvia. As most of Latvian breweries are of small size
and generally produce for local market, they are not affected by the EU or national legislation
on energy efficiency; therefore the global trends to increase energy efficiency have weak
effect on them. Increased resource and energy efficiency could help these breweries reduce
production costs and environmental impact from beer brewing. The aim of this study is: (1) to
analyze the historical resource and energy consumption in case study brewery and compare it
to available benchmarks and (2) to determine the potential resource and energy efficiency
improvements for the case study brewery. To evaluate the efficiency of resource and energy
consumption in the brewery, two year (2011-2012) historical energy and resource
consumption data is analyzed and compared to the recommendations of the Reference
Document on Best Available Techniques in the Food, Drink and Milk Industries (BREF)1, and
other studies on energy and resource performance of medium-sized breweries. The
determined specific water consumption corresponds to the typical benchmarks given in BREF.
Specific thermal and electricity consumption exceeds the reference values. To investigate
energy consumption patterns in brew house process, the heat losses are calculated. The
results suggest significant potential for energy savings by implementing heat recovery after
wort boiling. To determine the specific electricity consumption, a monitoring system was set
up for three different types of bottling (glass packaging, plastic packaging and barrels).
Results show that specific electricity consumption (kWh/hl) for different types of packaging
varies up to 7.6 times. Also, results of the implemented monitoring system provide valuable
data for determining the correction factors for different bottling possibilities for the brewery.
Highlights
Analysis of small size brewery provides energy consumption data lacking in literature
Monitoring of electricity use shows the differences between three types of bottling
Measured data can be used for correction factors for different bottling possibilities
Keywords
Energy intensity, Resource intensity, Small size brewery, Heat loss, Electricity monitoring
1.
Introduction
Industrial production is related to large consumption of energy and materials; therefore energy
efficiency in industry is pursued through various global and European Union (EU) initiatives (e.g. EU
20-20-20 targets). To implement energy efficiency measures, current energy consumption of
companies must be analyzed and compared to benchmarks for potential improvements.
Industrial companies can be divided into two parts according to their energy consumption – energy
intensive (e.g. pulp and paper, steel, chemical production) and non-energy intensive (e.g.
manufacturing and food industries) (Sandberg and Söderström, 2003). Due to higher energy
1
European Commission, 2006. Integrated Pollution Prevention and Control, Reference Document on Best
Available Techniques in the Food, Drink and Milk Industries, 682 pp.
consumption and, therefore, larger potential for improvements, energy intensive industries have
been in the scope of numerous researches. The potential energy efficiency improvements for these
industries have been identified through the analysis of the best practice and by setting benchmarks
for potential energy savings (e.g. benchmarks for energy intensive industries have been identified
within the project ODYSEE (ODYSEE, 2014)).
Presently increasing attention is devoted to energy savings in small and medium enterprises (SME).
The EU Energy efficiency Directive encourages energy auditing and implementation of energy
efficiency measures in SME (European Parliament, 2012). But as the majority of SME are energy
non-intensive industries, and energy costs typically constitute 1-3% of their total production costs
(Sandberg and Söderström, 2003; Muller et al., 2007), they are less interested in implementing
energy efficiency. There are also few studies on energy efficiency in non-energy intensive industries
and SME in the Baltic States; and the lack of available data limits the estimation of potential
improvements and establishment of relevant energy improvement benchmarks. Therefore, general
benchmarks for large size industries are typically applied for SME analysis. To improve the
knowledge on potential energy efficiency improvements, the analysis of the actual data for nonenergy intensive industries and SME is necessary.
Food and beverage production is one of the most important local industries in Latvia (Rosa and
Beloborodko, in press). Beer brewing has long traditions in Latvia; many breweries are famous for
their specific taste and the non-filtered („live”) beer. There are more than 20 breweries in Latvia,
most of which are small and medium size breweries. As these breweries generally produce for local
market, they are not affected by the EU or national legislation on energy efficiency; therefore the
global trends to increase energy efficiency have weak effect on them. To identify the potential
energy efficiency improvements and gather data for future benchmarking, a small size Latvian
brewery is chosen as a case study. The aim of this study is: (1) to analyze the historical resource
and energy consumption in case study brewery and compare it to available benchmarks and (2) to
determine the potential resource and energy efficiency improvements for the case study brewery.
The article is organized as follows: chapter 2 summarizes the applied methodology, chapter 3
presents the case study brewery, chapter 4 provides the results and discussion, and finally
conclusions are presented.
2.
Material and methods
2.1. Analysis of the historical resource and energy consumption
Company’s production performance can be described by specific resource or energy consumption
indicators (European Commission, 2006). The performance of case study brewery is determined by
analysis of production data for a two year period (2011 and 2012). The specific consumption of
thermal and electrical energy, water, malt and hops is calculated from monthly or annually
consumption data and normalized by the amount of produced beer. The thermal energy
consumption is calculated based on natural gas consumption records. Because of on-site heat
production and distribution through a single system, company’s records declare only the total gas
consumption, without distinction for process heat and space heating. The data for total electricity
and water consumption is gathered from on-site meters. Malt and hops are delivered in batches and
there is no daily accounting for their use. The specific malt and hop consumption is analyzed for
annual data.
To analyze the current resource and energy consumption and identify potential improvements, the
identified specific consumption indicators must be compared with benchmarks. Due to the absence
of a reporting system for companies to declare their production performance results, there is an
absence of statistical data for comparison of case study brewery with other breweries in the region;
the literature regarding specific energy consumption in small-size breweries is scarce as well.
Therefore case study results for a small scale brewery are compared with the benchmarks for
medium size brewery in the United Kingdom (UK) (Sturm et al. 2013) and BAT recommendations
based on data about modern large scale breweries in Germany (European Commission, 2006).
2.2. Analysis of brew house heat losses and monitored electricity consumption in
the bottling department
As historical consumption of thermal and electrical energy was identified to be significantly higher
than given by relevant benchmarks, the potential sources of inefficiency were investigated through
determination of heat losses at the brew house and monitoring and analysis of electricity
consumption in the bottling department.
The heat losses at the brew house are calculated to determine the energy efficiency of the brewing
process. Transmission heat losses are calculated for each considered process stage, while
evaporation losses are evaluated only for wort boiling, as in this stage steam is emitted into
atmosphere. Brew house heat losses are determined according to the method presented by Sturm
et al. (2013) for a case study of process-wise similar medium size brewery in the UK.
Three different types of packaging are used in the analyzed brewery - bottling in plastic (PET)
bottles, glass bottles and metal barrels. To determine the electricity consumption for each bottling
station, monitoring was performed from October to December 2013. Measuring points were set up
at five power inputs (2 at a glass bottling station, 2 at a PET bottling station, 1 at a metal barrel filling
station). Split core AC current sensors (CTV-A, CTV-B, CTV-C, CTV-D) and four-channel data
loggers (U12 U12-006) were installed. The sample recording time for all loggers was set to 5
minutes. The amount of bottled beer was recorded simultaneously with electricity consumption.
Eq. 1. was applied to convert from measured data to electricity consumption.
P = √3 ∙ I𝑣𝑖𝑑 ∙ 𝑈𝑣𝑖𝑑 ∙ cosφ
where:
P - power, W,
Ivid - average-current, A,
Uvid - average voltage at input, V,
cosφ-power factor.
(A)
3. Description of the case study beer brewery
The case study is a small size brewery producing 5 types of beer with annual production amounts
approximately 15 000 hl. The technological process of beer production includes milling of malt,
mashing, preparing and boiling of wort, beer fermentation, conditioning, filtration and pasteurization
and bottling. Beer production requires materials (malt, hops and water) and energy (electricity and
thermal). Electricity is provided from power grid, but process heat is generated in on-site natural gas
boiler house. During the beer brewing process a solid fraction – brewers spent grain - is separated
from mash. In the case study brewery, the brewers spent grain, which is high in protein, is collected
and supplied to farmers to be used as animal feed.
Due to the small size of the brewery, raw resource costs constitute the largest share of total
production costs, which is the most important concern, and constitute more than 50% of production
costs annually (Lursoft, 2013). Breweries representatives do not consider the costs of energy to be
of high concern. Electricity costs constitute only 3% of total production costs, but the combined
share of heat and electricity costs in 2012 was 9% of total production costs (Lursoft, 2013). Due to
an increasing energy price trend, brewery is interested to determine and identify potential efficiency
improvements.
4. Results and discussion
4.1. Analysis of historical data for energy consumption
The specific consumption of thermal and electrical energy is calculated from monthly data provided
by brewery. Average annual specific thermal energy consumption in 2011 was 245 MJ/hl and in
2012 – 231 MJ/hl. Average annual specific electricity consumption was 92 MJ/hl in 2011 and 82
MJ/hl in 2012. The relation between monthly beer production and specific thermal energy and
electricity consumption is depicted in Fig.3.
Specific energy
consumption, MJ/hl
Specific thermal energy consumption
400
Specific electricity consumption
300
R² = 0,7761
200
100
R² = 0,8462
0
0
500
1000
1500
2000
2500
Produced beer, hl
Fig.1. Specific energy consumption according to amount of produced beer
To evaluate potential energy savings, the specific energy consumption indicators for case study
brewery were compared with the recommendations of BREF (providing benchmarks for breweries
with capacity over 1 million hl of beer per year) (European Commission, 2006) and specific energy
consumption in medium size brewery in UK (Sturm et al., 2013) (see Table 1).
Table 1
Comparison of specific energy consumption
BREF recommendations (large size)
UK case study (medium size)
Case study (small size)
Specific thermal
consumption, MJ/hl
85 - 120
160 – 180
231 – 245
Specific electrical
consumption, MJ/hl
37.8 – 43.2
45–60
82 – 92
The specific energy and electricity consumption exceeds the best practice reference values in large
and medium size breweries. This could be due to better technologies, larger amounts of beer
produced and continuity of processes, as well as production of other alcoholic and non-alcoholic
products. Respectively, the cause of higher specific energy consumption should be investigated and
potential improvements should be suggested for small size breweries.
4.2. Analysis of historical data for resource consumption
The specific consumption for malt and hops is calculated from annual data and for water from
monthly data provided by brewery representatives. Both high and low specific water consumption is
seen per unit of beer produced. This is due to at least two week time shift between the consumption
of water and other resources (malt and hops) and the delivery of the beer. Therefore the annual
specific water consumption is compared to BREF and UK case study (see Table 2). In Latvian case
study specific water consumption is from 0.78m3/hl (2012) to 1.0m3/hl (2011), suggesting that water
consumption in this brewery correspond to recommendations for modern breweries.
Specific consumption of malt was 28.0 kg/hl in 2011 and 31.6kg/hl in 2012. Specific consumption of
hops was 0.073 kg/hl in 2011 and 0.074kg/hl in 2012. Annual differences of raw material
consumption can related to changing proportions of light and dark beer. The reported malt
consumption for large breweries is 1.4 times lower than for case study brewery, but for a small size
brewery the current consumption is relevant, taking into account large proportion of dark beer being
produced.
Table 2
Comparison of specific water consumption
Specific water
consumption, m3/hl
BREF recommendations
0.4 - 1.0
(large size)
UK case study (medium
0.64 – 0.72
size)
Case study (small size)
0.78 – 1.0
Specific malt
consumption, kg/hl
Specific malt
consumption, MJ/hl
20
–
–
–
28.0 – 31.6
0.073 – 0.074
4.3. Investigation of energy losses in brew house
Though the case study brewery is quite new (it is in operation only since 2002) the performance
analysis identifies that the specific thermal energy consumption exceeds the recommendations.
This could be because the installed equipment is not new but has been bought from older breweries
and its thermal efficiency may not the same as for new equipment. To determine heat loss in the
brew house, data was collected and calculations were made for a single brew batch of case study
brewery’s most popular beer – light lager. To identify the cause of the large energy consumption,
energy losses for each stage of brewing were calculated according to the method presented by
Sturm et al. (2013). To calculate heat losses all vessel dimensions are measured (vessels are
approximated to be cylindrically shaped), fluid filling height is calculated according to the amount of
ingredients filled in tanks, temperature regimes for each process are provided by brewery
representative. There is a shortage of information on heat loss for small size breweries in literature.
To analyze the obtained results a process-wise similar but higher capacity (250 000 hl beer per
year) brewery in UK was used as reference (Sturm et al., 2013) (see Table 3).
Table 3
Comparison of heat losses in cases study and reference brewery
Heat loss, MJ/hl
Mashing tank Mash filtration
Transmission heat Case study
0.047
0.59
loss Reference
0.06
Evaporation heat loss Case study
Reference
Heat lost due to spent Case study
0,80
grains discharging Reference
1.68
Overall heat loss Case study
0.85
0.59
during process Reference
1.74
Wort boiling
0.12
0.17
20.54
6.67
Whirlpool
0.12
0.04
20.66
6.84
0.12
0.04
The total heat loss in brew house is 22.22MJ/hl of witch 93% is heat loss due to evaporation of
water during wort boiling. In the reference case study total heat loss (taking into account losses at
fermentation department) is half lower - 9.68MJ/hl, mostly due to difference in evaporation heat
loss. Transmission heat losses are similar in both cases studies. Though Latvian brewery is smaller
and has higher specific thermal energy consumption, the specific brew house energy loses are
similar in both cases, which is a good indicator for a small brewery. As shown by Sturm et al. (2013)
the reduction of evaporation heat loss could noticeably contribute to reducing overall energy
consumption in the brewery. The recovered energy could be used to heat the water in the
accumulation tank. The evaporation heat recovery would reduce overall thermal energy
consumption, costs and fuel demand.
4.4. Monitoring of electricity consumption in the bottling department
The specific electricity consumption of different bottling stations can be determined by attributing the
electricity consumption to the volume of bottled beer. When the specific electricity consumption for
all three different bottling stations is normalized by production units, it can be compared.
Specific electricity consumption,
MJ/hl
The equipment for filling of 30 l metal barrels (KEG) has one power input for all its sections - barrel
rinsing, disinfecting and filling. Monitoring data for barrel filling station is available for a period from
10.03.2013. to 10.28.2013. taking into account 9 days of barrel filling. The statistical analysis shows
weak correlation between the amount of filled beer and specific electricity consumption (see Fig. 2).
This means that KEG filling line power consumption significantly influenced by factors other than
beer filling KEG barrels, that should be investigated in-depth to provide specific improvements.
At the glass bottle filling station beer is bottled in 0.33l, 0.5l glass packaging. The bottling station
consists of a bottle washing and rinsing, bottle filling, corking, and labeling conveyors. There are two
power inputs for glass bottling line - one for the labeling equipment and a lighting appliance
(hereinafter - glass bottle labeling equipment), and second for other sections (glass bottling
equipment). Monitoring data for glass bottling equipment is available for the period from 10.03.2013.
till 12.17.2013. (7 days of bottling). Due to monitoring equipment misstep, measurements for glass
bottle labeling equipment are available only for four bottling days. The trend lines (see Fig. 2)
indicate that the specific electricity consumption of the glass bottle labelling and bottling equipment
decreases with increasing amounts of daily bottled beer, which demonstrates higher efficiency at
larger capacity.
The beer is filled 1l and 2l plastic (polyethylene terephthalate, PET) bottles. Only clean and preinflated bottles are used, so there is no need for bottle rinsing. The bottling line consists of filling,
corking, labelling and multi-pack packing equipment. Monitoring equipment was installed separately
at two power inputs - one for multi-pack packaging equipment (PET packaging equipment), and
another for other sections (PET bottling equipment). The monitoring data for both inputs are
available for the period from 10.03.2013. to 12.17.2013 (6 days of bottling). The specific electricity
consumption for PET packaging equipment and PET bottling equipment varies greatly, former being
even 20 times larger than the latter (see Fig. 2). The trend lines for specific electricity consumption
for packaging and bottling of PET bottles show a statistically significant relationship (R2=0.9587 and
R2=0.912 accordingly).
7,0
Glass bottle labeling
R² = 0,9628
R² = 0,9587
6,0
Metal barrel filling
5,0
PET bottling
4,0
Glass bottling
R² = 0,6579
3,0
PET packaging
2,0
Glass bottling
station- Total
PET bottling stationTotal
R² = 0,5106
1,0
R² = 0,7128
R² = 0,912
R² = 0,1966
0,0
0
20
40
60
80
100
120
140
160
180
200
Bottled beer, hl
Fig.2. Specific electricity consumption at different power inputs
Fig. 2.also presents the summary of the specific electricity consumption for the entire bottling
stations in case study brewery. PET bottling station has the highest specific electricity consumption
in the analyzed brewery, glass bottling station – the second largest, metal barrel bottling station the lowest. The average specific electricity consumption of PET bottling station is 7.6 times higher
than that of metal barrel filling station. Even though in summary the PET bottling station has the
highest total specific electricity consumption, the PET bottling equipment has the lowest specific
electricity consumption of all equipment in brewery’s bottling department. Analysis of consumption
patterns for each power input shows that the most crucial sections for implementation of energy
efficiency measures in case study brewery are PET packaging and KEG filling equipment.
A significant energy consumption was also identified during production off-time was determined in
bottling department, potential savings could be provided by improved equipment management and
production planning. These indicative monitoring results different bottling stations in case study
brewery can be used to determine correction factors for benchmarking and for further analysis.
5.
Conclusions
Though beer brewing is not considered as an energy intensive industry, significant differences of
the specific energy consumption are observed for small, medium and large size breweries. The
identification of potential energy efficiency improvements and benchmarks relies on availability of
precise data. Currently such analysis for energy efficiency in non-energy intensive industries and
SME in Latvia is restricted due to small number of detailed studies. To overcome the existing lack of
data, within this research the specific energy and material consumption in small size Latvian
brewery is analyzed. In addition, this is one of few researches within Baltic States providing results
of electricity monitoring in industry.
The results of historical data analysis show that specific water and material consumption in case
study brewery corresponds to results reported in other studies, but the specific energy consumption
is significantly higher. To identify the cause of high specific energy consumption, the brew house
heat losses and electricity consumption for bottling was analyzed. The results suggest that the
highest heat losses in brew house result from water evaporation during wort boiling and energy
efficiency could be improved by recovering energy from steam. The electricity monitoring results
show that specific electricity consumption (kWh/hl) for different types of packaging varies up to 7.6
times. As well significant energy consumption during off-time is determined and important savings
could be provided by improved equipment management.
As determined, the specific electricity consumption for different equipment even in the same bottling
station can vary importantly. This also impacts the electricity savings potential for beer in different
packaging. One of possibilities to consider such differences is the use of correction factors. The
specific electricity consumption for different bottling station, which was determined in this study, can
be used for application of correction factors for particular brewery. Furthermore, the benchmarks for
identification of energy efficiency improvements in industry should be advanced so that they could
account for varying processes and potential improvements due to varying design of each
production.
Acknowledgments
Support for this work was provided by the Riga Technical University through the Scientific Research
Project Competition for Young Researchers No.ZP-2013/14.
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