how to calculate the feasibility of a solar district ... mokymai/sdh workshop... · how to...

How to calculate the feasibility of a solar district heating project

Workshop on Solar District Heating

Lithuanian Energy Institute in Kaunas

November 4th 2014

Daniel Trier

dt@planenergi,dk

www,planenergi,dk +45 2517 0400

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Overview

• District heating in LT and DK

• Case studies: Raseiniai & Radviliškis

• How to make rough estimation of feasibility for other plants

• Conclusions

SDH workshop in Kaunas, Lithuania, November 4th 2014

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Lithuania & Denmark

• Solar irradiation: Approximately the same.

Other circumstances determine the potential for SDH (such as political decitions, ownership of district heating companies…)

• The future: • Lithuania: More biomass based district heating in the future

• Denmark: More biomass based district heating (CHP/boilers)

• But how much? – What to do in the future?

DK government: Will not “put all eggs in one basket”, i.e. avoid being dependent on biomass only. Therefore the future energy supply should be a mix of several solutions: Wind + heat pumps + biomass + biogas + solar heating + PV …


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Lithuania & Denmark


• Lithuania: More and more biomass for (district) heating.

• Europe: More and more biomass for CHP / (district) heating.

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Lithuania & Denmark


• Lithuania: More and more biomass for (district) heating.

• Europe: More and more biomass for CHP / (district) heating.

Lithuiania is not the only country looking at biomass as RE source.

Demand will increase in the future.

Price of biomass will …?

• Even if there is plenty of biomass, the price will be determined by the international demand.

• No supplier can cut the supply of solar heat.

Solar heat makes you more independent and less vulnerable!

Increase! (How much?)

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Lithuania & Denmark


• Denmark: Long tradition for the municipalities to make energy plans. (Estimating ressources, evaluating different options for the future.)

• District heating is a long term decision. – Not only ”here and now”. (When you plan a new DH network you also look at long time periods.)

SDH requires a look at the long term perspectives.

• Feasibility does not just mean ”how short is the payback time?”

Compare the economic situation for the district heating company in two scenarios: With SDH and without SDH. If the overall costs per year is lower with SDH then why not?!

• Investment in SDH will not replace investment in boilers, but fuel.

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Other benefits


• A solar heating system can make it possible to shut off boilers in summer.

Longer lifetime of boilers.

Possibility of maintenance without using more expensive backup fuels.

Less CO2, SO2, NOx.

Less traffic for supplying biomass for the DH plant.

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Case studies

• Raseiniai & Radviliškis was investigated.

Best results for Radviliškis.

If biomass prices are assumed fixed, then most systems are too expensive (but one gives approx. the same heat cost).

If an annual increase in biomass prices of 1 % per year is assumed, then a SDH system result in savings.

• Radviliškis results are presented in the following slides.


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Case studies

Assumptions:

• Collector price depending on area (200-300 €/m2 for 2,500-27,500 m2).

• ~1 €/MWh for solar heat (mainly electricity for pumps)

• Annuity loan with a real interest rate of 3 % (~5 % interest rate with ~2 % inflation) amortized over 30 years.

Questions:

• What is the total costs for supplying the heat with the present system (reference scenario)?

• What is the total costs for supplying the heat if a solar heating system was installed.

Can the saved operating costs match the payments for a loan?


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Case study: Radviliškis

• Solar heat production from the collectors and solar fraction:


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• Reference scenario: Average heat price of approx. 25 €/MWh without increased biomass price (27-28 €/MWh with increased biomass price).

• Most feasible size: Approx. 22,500 m2 of collectors and 5,600 m3 tank.

• Savings in operation & maintenance (O&M) costs: ~288,000 €/year.

• Investment: 5.3 M€.

Capital costs: 272,000 €/year. (Net savings: 15,000-16,000 €/year.)

Average heat price for the solar heat:

272,000 €/year .

22,500 m2 x 500 kWh/m2/year

= 24 €/MWh + 1 €/MWh (for O&M) = 25 €/MWh for solar heat.


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• If an annual increase in biomass prices of 1 % per year is assumed:

• Similar result if 10 % lower investment costs is assumed.


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Results:

• Since the biomass price is expected to increase in the future a solar heating system will most likely be profitable for the Radviliškis district heating plant already now.

• The average heat production price is lower than the reference in the scenarios with solar collector areas of 15,000 m2 or more.

• An optimum solar collector area along with a tank storage is found at around 22,500 m2, but other sizes could also be feasible.

• The SDH system is still feasible even if only an annual increase in biomass prices of about ½ % per year is assumed.


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Guidelines

• List of fact sheets available at www,solar-district-heating,eu/factsheets


• 1,1 Overview of SDH implementation steps

• 2,1 Solar heat combined with other fuels

• 2,2 Where to place the solar collectors

• 2,3 Feasibility study

• 2,4 Questionnaire for SDH site assessment

• 2,5 Ownership and financing

• 2,6 Calculation tools and methods

• 3,1 Permissions from authorities

• 3,2 Tendering and contracts

• 3,3 Performance guarantees

• 4,1 Supervision of construction

• and commissioning

• 4,2 Monitoring

• 6,1 Interaction between SDH plant and DH network

• 6,2 Decentralized integration of ST in DH networks

• 6,3 Control strategies

• 7,1 Solar collectors

• 7,2 Storage

• 7,3 Pipes, pumps and pressure ratings

• 7,4 Heat exchanger

• 8,1 Temperature variations

• 8,2 Safety equipment

• 9,1 Nomenclature

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Guidelines

• List of fact sheets available at www,solar-district-heating,eu/factsheets


• 1,1 Overview of SDH implementation steps

• 2,1 Solar heat combined with other fuels

• 2,2 Where to place the solar collectors

• 2,3 Feasibility study

• 2,4 Questionnaire for SDH site assessment

• 2,5 Ownership and financing

• 2,6 Calculation tools and methods

• 3,1 Permissions from authorities

• 3,2 Tendering and contracts

• 3,3 Performance guarantees

• 4,1 Supervision of construction

• and commissioning

• 4,2 Monitoring

• 6,1 Interaction between SDH plant and DH network

• 6,2 Decentralized integration of ST in DH networks

• 6,3 Control strategies

• 7,1 Solar collectors

• 7,2 Storage

• 7,3 Pipes, pumps and pressure ratings

• 7,4 Heat exchanger

• 8,1 Temperature variations

• 8,2 Safety equipment

• 9,1 Nomenclature

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Guidelines

• Include the following subjects: • Introduction to SDH • Preliminary investigations • Permissions, tendering contracts and guarantees • Implementation • System • Components • Precautions

• A list of fact sheets are available for download on www,solar-district-heating,eu/factsheets

• If you have questions regarding these fact sheets do not hesitate to contact me.


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Conclusions

• Solar heating makes you less dependent on fuel supply and fuel costs, extends the lifetime of the boilers and reduces GHG emissions.

• Solar district heating can be produced at heat prices in the same range as biomass heat.

• Feasibility is not necessarily the same as short payback time.

• Make the comparison of the total heat costs with and without a solar heating system. If the costs are lower then SDH is feasible.

• If not now, then at least keep it in mind for when the biomass prices goes up….


Jægerspris, DK – 2013

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Thank you for your attention

+45 2517 0400

dt@planenergi,dk

www,planenergi,eu


how to calculate the feasibility of a solar district ... mokymai/sdh workshop... · how to...

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