The first short presentation was about the combination of the Demand Side Management (DSM) with another way of storing cold energy.

 

Please open the file on the left.

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I started with the situation in India:

1. There is a fast development of Renewable Energy, mostly of the two volatile types Solar and Wind.

2. With the weak grid (in comparison with present and future demand) and in various regions even absent, it is a good moment to decide between heavy investment in a grid that just follows the demand or more flexible approaches.

3. Much of the electricity is used for cooling.

4. India seems focused on electrification of the energy mix, fuels seem to go into the background, the last years.

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How this situation asks for DSM:

1. DSM is a flexible solution for a weak grid. It is when not only the supplier adapts the power to the demand, but also the consumer adapts the time of consumption to the market. In the figure on slide 2 one sees that in order to avoid a critical level, the consumer can shift the time of operation of some installation. If that is not possible, a storage can do this time shift.

2. Everybody is aware that DSM is a needed solution to avoid more black-outs. ​

3. Less aware is the consumer about the opportunities:

   • Protecting the own enterprise;​

   • Saving on the bill.

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Slide 3 is on the technology of storage.

Everybody is talking about storing energy in batteries, but when we see from the first slide that much electric energy (> 40%?) is eventually converted in an electric chiller, then the storage can be done directly in a cold storage, e.g. an ice storage.

The advantages are clearly stated on slide 3. About the investment: it was difficult to get prices per kWh, like they are available in statistics for Li-Ion batteries. I assume 180$/kWh of capacity and between 12 and 20% of that for ice storage, which depends much on the size. The last one "Big power without big chiller" refers to the need of a chiller that must be dimensioned on the peak demand of cold, even if that is only few hours per year. That is a bottleneck.

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Slide 4 shows a 1-day spreadsheet simulation of a consumer with a chiller and a cold storage. The chiller has max. 150 kW cold power and the consumer demands 200 kW in the afternoon. This simulation shows the opportunities of DSM mentioned above:

• Protection: the ice storage will continue to give 200 kW even with a black out:

• Saving on the bill: the diagram shows how energy is stored during the cheap tariff period. It appears to me that the evening hours are expensive in India. The chiller is switched off in those hours. 

 

The subscriber to ​the Newsletter can download the spreadsheet file on the left and make simulations of the own situation. There are also prices per kWh of ice storage, which the user can change. These prices are calculated as a function of the size of the storage. This can also be changed by the user.

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Slide 5 shows how to make the situation with the DSM and ice storage even better, by using dynamic tariffs of electrical energy (to negotiate with the own or another energy supplier) and by using an innovative technology, which I didn't see around but discussed with an important Indian chiller company.

• Dynamic pricing allows to exploit still more the extreme tariffs on the spot and day-ahead market for electricity. The extreme low tariffs can be used to put the chiller and storage at maximal regime. This flexibility should improve still more the profitability of the ice storage and is also better for the community, because you are more incentivised to adapt with more precision to the exact moments of extreme stress and calmness on the grid.

• The technological proposal is to put an Internal Combustion Engine (ICE) on the chiller, instead of driving it with an electric motor. This will relieve the grid and supply cold during a black out. The heat will be led into an absorption chiller so that the fuel is nearly completely used. The combustion gases can increase the temperature of the water from the motor, which is not really high enough for a good efficiency of the chiller. A modest generator on the same axis can even give some electricity for pumps, fans and other emergency users during the blackout, or to charge electrical batteries. Together with an ice storage, the ICE will not have to start/stop often, which will increase efficiency and lifetime. I am sorry that the ICE can be confused with the ice (in the storage) but if you touch it, you will feel the difference!

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Slide 6 proposes experiments in India with the 3 presented innovations:

1. Storing energy in ice banks instead of in batteries;

2. Using Dynamic Tariffs;

3. Using an ICE driven chiller.

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The best way to start is to look for users, where the Security of Cold Supply is essential. The simulation spreadsheet on the left doesn't show a very attractive ratio between yearly savings and the investment. Even if the Net Present Value is very interesting (and I like the NPV much better than the Payback Time), it is better to start with users, that are anxious about black outs. Hotels, hospitals and food distribution will suffer severely if they cannot have continuous cooling. It suffices to imagine if tons of food will have to be discarded. Also some industries like food or pharma will make good candidates. 

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It was interesting to hear during the Question Round of the webinar how the infrastructure problem for the Dynamic Pricing could be solved. I responded by proposing an initial experiment with a cooperation between an industry and a supplier. The best is to look first to: 

         https://www.next-kraftwerke.com/company/philosophy

and see if something similar is offered in the region. This German website is in English and explains how even retail users can have 96 different tariffs per day instead of only 3, and with much deeper "discounts" for who purchases energy at the right moment.

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Back to our experiments: if they are promising for a couple of projects (it would be good to diversify the consumers between several sectors, like above), then more of the same consumers can be invited to copy the experience. Obviously it is important to make a Measurement and Verification Plan for the experimental projects, because there is much to tell about after this experiment and realistic data must be presented to the market.

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It is to be expected these 3 components or also only 2 of them fit so well to each other, that nice pilot projects can be started. Moreover, in case of success, there are many consumers where the concept can be cloned. There are many consumers, where cold production is essential.