Results for Helsinki energy decision 2015

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Scope

What are the more accurate results for Helsinki energy decision 2015?

Answer

Scenarios examined

We examined two different sets of scenarios. The first set was a collection of suggested policies that were interesting to examine for the decision making. The second set was more technical, and it aimed to find the differences in the cost-efficieency of different power plant solutions rather than actual feasible solutions. The sets were as follows:

Suggested policies

Business as usual (BAU)
The already existing power plants are renovated to burn biofuels and will remain in use as long as possible.
Process heat
As much of the excess eat from different processes will be taken into use. The most important heat sources are the Neste oil refinery in Porvoo and the nuclear power plant possibly built in Loviisa that produces CHP.
Helen's proposition
The suggestion of Helen brought out in June 2015. New biofuelled heat plants are built and CHP is slowly given up.
Zero investment
As little new construction is carried out as possible.
Carbon neutral 2050
All fossil fuels are given up by 2050 and are replaced by biofuels and process heat.
CHP bio
Electricity and heat are co-produced in especially the new Vuosaari C -bio-CHP-plant.
Distributed and sea
Heat is produced with distributed geothermal, heat pumps and bigger heat pump plants taking heat from the sea as possible.


The technical scenario set includes all existing and suggested new power plants. They are then inspected scenario to scenario in a rough order of cost-efficiency, beginning from the best. In the next scenario then shows which remaining plants will be run to optimise cost-efficiency.

All1
All plants are in use.
Loviisa2
District heating is mainly produced in the nuclear heat plant in Loviisa. This is when the small and insignificant plants are shut down, so they're not confusing the interpretation of further analysis.
DataAndSea3
District heating is mostly produced from excess heat from data centers and with sea heat pumps. Loviisa nuclear heat is not taken into use.
NesteAndDeep4
District heating is mostly produced from excess heat from Neste, in Viosaari C power plant and with deep drilling. The data center heat and sea heat pumps are not used.
Existing5
District heating is mostly produced with the existing plants, meaning Hanasaari, Salmisaari and Vuosaari CHP plants. Vuosaari C is not built.
Backup6
Disrtict heating is mostly produced in the back-up oil and gas heat plants.
Lowcost
Only the most cost-effective plants from the previous scenarios are run. This means Loviisa nuclear plant, data centers' and Neste's excess heat, Katri Vala heat pumps and the small back-up oil heat plants.


Building stock development and other background information

The increase in the number of buildings is more or less what the zoning scheme predicts the population and building stock to be, meaning 42% from 2010 to 2050. The increase looks greater in the image, because the buildings already demolished are seen as never existed, and this makes the historical growth seem greater that it in truth is. The time period also goes on far further than 2050 and the increase is assumed to remain stable also after that.

The energy use of buildings is the single greatest user of energy in Helsinki, and this is why it is especially important to examine. The increase in building stock also increases the energy need, but according to the model the need doesn't increase or even decreases by a fifth. There are two main reasons for this. First of all, the new buildings are assumed to be very energy efficient, so the increase in the energy consumption is smaller than the increase in building stock would indicate. Also, old buildings are renovated, which increases energy efficiency and decreases the energy need of current building stock. However, the full energy efficiency policy (Energy saving total) is quite radical, so the decreased energy consumption in the model is very difficult to achieve. The only real way to do this would be to demolish the older, most inefficient building stock and built new, modern an efficient in its place. This is not something assumed in the model.

The prices of the fuels are key background information, and especially the difference in prices between the fuels often resolves, which plants the model shows should be run and what not. Forecasting the price of energy to fifty years away is very difficult if the predictions need to be accurate. We have dug up respectable estimates from the United States and the UN's International Energy Association IEA, but the uncertainties are still great. There estimates assume the price of natural gas to increase more rapidly than others. This leads to the gas plants Vuosaari A and B and smaller gas heat plants seem to have low cost-effectiveness, and thus should not be run. This should be kept in mind when interpreting the results.

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Energy production

Behind the model is the energy balance calculated for district heating. The production of district heat has to match the current consumption, whether it's heat or freezing outside. The model calculates the energy need and production for different days based of the outside temperature and finds the required plants for the situation. Every plant has a maximum capacity that can't be crossed in the model. So the most cost-effective plant runs with full power. If more energy is needed, the second most efficient plant is turned on, and so on. This daily information is summed up for the whole year, so the situation can be examined over decades. It is good to notice that very high power requirements are rare, so a big portion of the power plant capacity stays idle for long periods of time.

Electricity was examined in this assessment only as a convenient side product, but it also plays an important role. Sofia assumes that electricity can be bought and sold in the national network without limits with a fixed price. We were supposed to add a part to the model that takes into account the changes in electricity prices, but there wasn't enough time to finish it. Either way it is important to examine the different options' effect on the electricity needs in Helsinki. In previous years and currently Helsinki produces more electricity than consumes, and selling electricity is actually good business or the city. This is because of efficient CHP-production that has been the basis of district heating in Finland in the past few decades.

However, many of the new options examined are ones that might not produce any electricity and might actually consume it quite a lot. So if the current coal and gas plants are run down there will be an electricity deficit in Helsinki, that needs to be filled from the national network one way or another. Practically this means the Nordpool area that also include Sweden, Norway and Denmark.

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