Showcase Hamburg

hamburg_newsletter1The e-harbours Hamburg showcase focuses on the application of smart energy solutions in large-scale industrial, commercial and infrastructural properties in a typical harbour environment. The solutions that are taken into consideration cover a wide range: Local load shifting mechanisms, integration of local consumption and/or production devices into a virtual power plant, combined generation to cover power and heat demand, and options for energy storage in the form of electricity, heat or cold. Although technical possibilities are assessed within each case study, the economic viability of smart energy solutions lies at the centre of attention, following the question: What makes a smart grid profitable? The target is therefore not to build technically viable demonstrators, but to introduce and assess smart energy solutions in today’s market-based environment and in accordance to companies’ expectations regarding return on investment, operational security etc. Please note that due to non-disclosure agreements with all cooperating companies, no company names can be stated here, and no precise figures can be provided.

Case study 1: Chemical production plant

Project description: The company operates a medium-to-large production plant in the Hamburg Harbour, where it produces a broad range of semi-finished goods from raw materials. The plant is operating continuously, but production is organized manually in batches. Production steps vary according to the specific products. What makes the situation very interesting from a Smart Energy point of view is that the company recently installed a large CHP (combined heat and power) plant that now covers a large part of the company’s thermal and electric energy demand.

What we have done

In two extended on-site visits, the flexibility potentials of consumers were analyzed. Core power consumers are agitators and pumps for fluid or semi-fluid materials. Another large set of consumers are compressors used in a central cooling system, which is used to cool down material between production steps, and shows some interesting potential for flexible operation. However, the current system will be replaced by a more efficient and modern one in the medium future. Here, recommendations were formulated by the e-harbours team regarding a flexibility-providing design and layout of the new system, for example through the inclusion of a phase change material (PCM) storage device, which would allow the storage of cold.

Another notable and very interesting detail is the plant’s high demand for hydrogen, which is used as a production input. Hydrogen demand is stable over time, and is currently met by delivering large quantities of hydrogen by truck. It was decided to investigate the option for producing hydrogen on-site via electrolysis, which would represent a large consumer that could be flexibly operated in order to increase overall flexibility at the site.

Most attention was directed towards the newly installed CHP plant. Since the formally used gas-fired boilers are still operational, the CHP could be switched off flexibly whenever there is a surplus of energy in the grid. Potential business cases were assessed for this, focusing mainly on the provision of negative reserve capacity. A techno-economic analysis was carried out to investigate possible revenues and additional costs, based on energy market data series and the company’s demand profile and individual price components.

Due to the high heat demand of the factory, an additional option was investigated: The retrofitting with electrical heaters to allow the uptake of even more surplus power in order to stabilize the grid (this concept is called “power-to-heat” in literature, and could also be titled “power-to-saved-gas”, as it uses available surplus electricity from e.g. wind turbines to replace fossil fuels in heat generation, usually natural gas). By this, the amount of available reserve capacity could be almost tripled. Also for this option, a cost-benefit analysis was carried out.

power_to_heat_english_500

The Power-to-Heat principle

Results

Exploitable flexibility on the consumption side is quite limited: Agitators and pumps are hard to operate in a flexible way due to their rather intermittent and random operation within the production process, which is partly manually controlled. Although flexibility is available in theory, exploitation would require a major logistic and investment effort in order to control the many dispersed and autonomous consumers.

On-site hydrogen production is technically feasible, but not competitive due to the low prices the company pays for hydrogen from external sources.

The most interesting potentials lie in the flexible operation of the CHP plant in order to provide reserve capacity. At minimal investment costs, revenues can be expected that are equal to several percent of annual electricity costs. However, the CHP alone does not reach the minimum amount of 5 MW of flexible load that is the threshold for direct market entry on the reserve capacity market in Germany. In order to benefit, the company would have to rely on a reserve capacity pool operator, who would in turn charge for his services.
This is where the “power-to-heat” option comes into play: Revenues can be almost tripled, and the increased amount of flexible load allows a direct participation on the reserve capacity market. Additional investments are required, but would amortize in about two years.

Recommendations

The company was endorsed to realize a flexible CHP operation strategy and to investigate the options to implement a power-to-heat appliance. Contacts to service providers and poo operators were already facilitated by the e-harbours team.

On a policy level, there are several recommendations to facilitate implementation in a case like this:
Access barriers to the reserve capacity markets should be reduced, and the market role og pool operators or “Demand Response Aggregators” should be properly reflected in the energy market design in order to encourage and facilitate the exploitation also of smaller flexible potentials. For more information, see reports on WP 3.5 and 3.7.

Reports and more information

[See below]

 

Case study 2: Container Terminal

Project description: Second case study within the Hamburg showcase is a container terminal in the port of Hamburg. It is the most modern of several terminals in Hamburg. With a yearly cargo capacity of 2-3 mio TEUs, it is also a rather large terminal. The terminal’s loading infrastructure (container and storage bridges) are completely electrified, and are largely controlled automatically, i.e. without a human operator steering the crane. The terminal operator is traditionally very engaged in increasing efficiency and reducing ecologic impacts of its facilities. Also, the company is considering several options for on-site production of electricity. Concerning grid infrastructure, none of the terminals in Hamburg is facing physical load constraints. However, peak-load related costs for grid utilization are quite substantial. In addition, the German grid code foresees further reductions in grid utilization costs if the load curve of a consumer is largely stable over the year. Together, this makes quite a strong case for load shifting operations. Another aspect that is also relevant in the case of some container terminals is a peak/off-peak tariff, where off-peak prices per kWh are slightly lower than during peak times.

What we have done

Regarding the loads caused by different consumers on the terminal, only rough estimations were available, since they are not currently measured and logged for single parts of the terminal or even separate consumers. Therefore, it was decided to install measurement equipment at the terminal.

Data was collected on 30 measurement points: Measurements of refrigerated containers started in October 2013 with a time-resolution of one minute. Measurements of main power supply connection and supply of separate consumer groups like gantry and container cranes were carried out over one and a half months starting in December 2013. Using a time-resolution of one second enables to analyze short-term load peaks caused by container bridges. It resulted that one of the largest single consumers are the container bridges which load and unload the container ships with a share of nearly 25 % of the total electricity consumption. Depending on the container weight, they take up to several MW during the lifting sequence. When lowering containers, the winch motors act as brakes and feed a large share of the energy that was consumed beforehand back into the grid. Due to their individual and not aligned operation mode, load peaks can add up drastically if, by coincidence, all bridges are lifting simultaneously. Conversely, in other moments loads caused by lifting and power outputs caused by lowering may level out themselves, or even cause a net feedback into the grid. This becomes apparent when analysing the overall load profile on a per-second scale: Here, very large and short termed load variations occur. Load peaks can reach well over 15 MW for a couple of seconds, with load minima as low as 1 MW.

Refrigerated containers make up another very large group of consumers with a share of nearly 35 % of the total electricity consumption. Refrigerated containers are used in the global transport chain for storing chilled or frozen food. Each of these so-called “reefers” has an electrical on-board cooling unit. While on a ship, they are connected to the ship’s energy supply. At the terminal, they are plugged into the electrical grid. The investigated terminal has connection points for 2000 reefers. Depending on the amount and type of reefers connected, the load caused by reefers typically ranges from several hundred kW to around 2 MW.

Since own consumption of local electricity production is getting increasingly more important, apart from flexibility provision based on measurement data impacts on load profile by integration a wind turbine or a combined heat and power plant for onsite electricity generation was analyzed. For this calculations were conducted for a wind power plant with a capacity of 3 MWel and a CHP plant with a capacity of 2 MWel. Therefore, electricity generation by wind turbines was calculated on basis of local wind velocity values.

 

Findings

Actively controlling the operation of container bridges in order to reduce load peaks was not desired by the project partner. Even though technically possible, the highly optimized and time-sensitive automatic unloading process is too complex and critical. An option would be the installation of a very short term storage buffer. Measurement results show that indeed most of the extreme load deviations even out over the average of 15 minutes. The highest measured load peak on a per-second basis is almost twice as high as the highest load peak on a 15-min. basis. This means that the extreme load deviations are not nearly as strongly reflected in the company’s billed load profile. As a result, there is currently no business case for evening out load variations with short term buffers.

Reefer containers, on the other hand, can deliver flexibility over a larger timespan. They are very well insulated, as they have to maintain their temperature level for several hours even if not connected to the grid, for example during road transport or loading/unloading at the terminal. Especially reefers for deep-freezing allow a rather broad temperature range between e.g. -18°C and -22°C. Therefore, depending on their current temperature, the cooling devices of reefers could be switched off for a certain amount of time (several minutes to several hours) if a local smart grid has the necessity to reduce load. Conversely, they can be cooled down on purpose at times of high availability of electricity.

Technical aspects do not obstruct the use of reefers for load shifting purposes – although a considerable research and development effort will be necessary to connect reefer control infrastructure and software to logistical and energy management systems at the terminal.

The most interesting application in the Hamburg terminal would be to even out the load curve of the entire terminal in order to reach reductions in grid utilization costs. Also, a reefer-based load management system can be used to profit from a peak/off-peak tariff. Possible savings would amount to several percent of the terminal’s total electricity costs, which is a significant amount in absolute terms. Necessary investments would amortize after far less than a year. However, realization of this business case is subject to two conditions: Firstly, the shiftable load represented by reefers must be large enough to even out the load profile for the whole year. Measurement results show that load level caused by reefers exceeds load level of occurring load peaks in the total load profile at all times during the considered period. However, it has also to be taken into consideration if actually connected reefers are able to provide required energy amount. Since the energy consumption of each reefer is dependent from many factors reliable statements about required time scale of flexibility and number of reefers is not possible with present measurement data.

Secondly, the business case itself is questionable: The grid fee exemptions are under revision by the EU to clarify whether they are coherent with EU market regulations. A decision by the EU is expected for late 2013, and should bring clarity to this issue.

A solid application for a reefer-based load management system would be the optimized use of local renewable energy production, e.g. by a wind turbine. However, space constraints at the investigated terminal make this option unlikely in the medium future.

Apart from mentioned flexibility options results from simulating an onsite power generation show that on site generation leads to reduction of electricity consumption provided by public power grid over the considered timespan amounting 18 % in case of installation a wind turbine and 27 % in case of CHP operation.

This reduction has influence on total energy bill of the container terminal. Scaling-up the energy yield for a whole year providing by a wind turbine (considering seasonal variations in the wind scenario) and CHP annual cost savings amount about approximately 10 % in the wind turbine scenario and about 13 % in the CHP scenario. In the second scenario additional costs for fuels and levies are taken into account.

Recommendations

Regarding the reefer-based load management system, a research& development partnership should be initiated between manufacturers of reefer control interfaces and terminal control systems on one side and terminal operators and shipping lines on the other hand: Scaling-up potential is significant and in other countries, a larger number of business cases could be available. Also, on-ship applications are imaginable.

On the organizational side, it should be cleared whether contractual obligations allow the use of reefer containers (which are not the property of the terminal) for load management purposes.

Regarding legislation, it would be advised to create dependable and stable regulations for grid fee calculation and exemptions, which can serve as a solid basis for smart energy business cases. For further information, see WP 3.5 and 3.7 reports.

 

Reports and more information

[See below]

Case study 3: Cold storage warehoses

Project description: Refrigerated warehouses for storing frozen or cooled food are found at most commercial harbours around the world. In most cases, they are cooled by vapor-compression refrigeration using electric compressors. Temperature within the warehouse is set according to the products stored, and controlled automatically by thermostats. Compressors also run automatically depending on the demand for coolant in the refrigeration system. If cold storage warehouses are used for load shifting operations, the refrigeration system and thus the power consumption could be controlled in order to reach a certain increase or decrease in total load. Due to the good insulation of cold storage warehouses and the large mass of cargo stored, temperatures within the warehouse will only rise slowly if compressor operation is interrupted.

What we have done

As mentioned above, three cold storage warehouses were analyzed in depth for e-harbours. Analysis was conducted by external consultants who have vast experiences in the sector of cold storage. The scope of work included a field visit to each of the three warehouses and discussions with the operating staff in order to get first-hand data and information.

Within a cold storage warehouse, compressors represent the largest electric consumers, even though ventilators, lighting etc. also have a certain share. Total installed power in the analyzed warehouses was in the magnitude of 300-800 kW each.

Warehouse operators provide 15-min. load profiles of the years 2010 and 2011. This information was complemented with data on thermal behavior of cold storage warehouses derived from literature. This data input was used to calculate the available flexibility. In order to facilitate calculations, it was assumed that the cold demand was rather constant throughout the day. Thus, assuming that cold demand was linear to the power consumption, the average load over a 24h period was calculated in order to determine the baseline power demand.

Possible revenues were then calculated for different business cases. For this, the contracted consultancy used a simulation tool for virtual power plants that optimizes flexible consumers based on different business case scenarios. The business cases that were assessed include several of the universal business cases listed in the e-harbours “Report on Strategies and Business Cases for Smart Energy Networks” (see download section).

Findings

It resulted that the warehouse operators could save around 7% on total energy costs using the business case of contract optimization, equivalent to a low 5-figure sum in the analyzed cases. Savings are mainly realized through reductions in grid fees that are available to customers that consume most energy during off-grid times. It has to be noted, however, that one of the assessed warehouses already made use of this business case in the assessed period using a basic timer mechanism – in this case, additional savings through an optimized control are much smaller.

Another attractive business case is to source energy directly from the spot market. In order to save energy costs, it is attempted to shift a large part of the energy consumption to times with low prices. Due to the relatively small spread between peak and off-peak prices in recent times, revenues are not as large as expected and range between 5 and 7% of annual energy costs.

To enable flexible operation of cold storage houses, several investments for a central controlling system are necessary, with the amount depending on the previous automatization level of the warehouse. It resulted that for the investigated cold storage houses, potential savings did not justify additional investments in the view of the respective owners. However, one company did include a smart control system in a newly constructed warehouse outside of Hamburg.

Recommendations

In order to minimize investments, smart energy initiatives targeting cold storage houses or similar consumers should focus on properties that are being built or retrofitted. Also, new warehouses usually have better insulation, resulting in larger overall flexibility over time.

A strong argument for flexible operation could be if renewable energy capacity is already present or could be installed at the cold storage site – in such a case, own consumption of renewable energy could be optimized, leading to lower total energy costs, while improving the greenhouse gas emission profile of the respective warehouse.
This interactive simulation visualises the influence on the own consumption level if cold storage warehouses are used to store renewable energy during peak times.

On an organizational level, it has to be ensured that flexible operations does not affect product quality – even if temperature boundaries are adhered to, too many temperature variations may lead to accelerated product ageing. This topic may require further investigation. For further information, see WP 3.5 and 3.7 reports.

 

Reports and more information [for all case studies]

Reports

Articles

  • Roundtable event “Intelligent energy solutions for the Hamburg Harbour”
    As part of the energy transition, the flexible adjustment of production and consumption is becoming increasingly important – and profitable. The e-harbours Hamburg team is organizing a roundtable event to inform and bring together all relevant stakeholders. Read more »
  • Numerous research projects on Smart Energy Systems were implemented in the last few years. Experts and the Federal Government of Germany both agree
    that the transformation of the energy supply system towards renewables is not possible without intelligent and decentralized energy solutions: Demand Side Management for large consumers, smart operation of CHP plants and intelligent storage options. Read more in Newsletter #4 »
  • The e-harbours expert group on Smart Energy Networks has produced an extensive analysis of the business cases that can make a Smart Grid profitable. Read more in Newsletter #3 November 2012 »
  • What makes a Smart Grid profitable? Shifting energy consumption is one of the most important goals of the Smart Grid. As the share of renewables in the energy mix is rising, we have to adapt our power consumption. Read more in Newsletter #2 May 2012 »
  • Leaflet: Overview of INTERREG projects at HAW Hamburg

Links

Videos

  • Presentation of e-harbours (English)
  • Presentation of e-harbours (German)
  • Presentation of the Center for Demand Side Integration at HAW Hamburg (German)

Media exposure

Contact

  • Project leader: Hans Schäfers hans.schaefers (at.) haw-hamburg.de, Hamburg University of Applied Sciences (HAW Hamburg)

  • Project coordination & communication: Philipp Wellbrock eco.wellbrock(at.) googlemail.com, Hamburg University of Applied Sciences (HAW Hamburg)

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