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Dr. Congxiao Shang Room No.: ENV-2A82: Low Carbon Energy Basic Economic Analysis ENV-2A82 (2011/2012): Low Carbon Energy N.Keith Tovey ( ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Room No.: TP Recipient of James Watt Gold Medal for Energy Conservation 1

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Objectives of this Session To examine methods to assess whether an energy project is economically viable. Energy is a multi-disciplinary subject and other criteria are also needed PHYSICAL TECHNICAL ECONOMIC ENVIRONMENTAL SOCIAL POLITICAL Fuel Poverty Issues UEA Heat Pump Scheme ENERGY See Webpage for details

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2.1 Introduction An energy project should consider whether to: 1) promote energy conservation, and/or energy efficiency. Is there a difference between Energy Efficiency and Energy Conservation? 2) develop low carbon energy resources, nuclear, wind, tidal, wave, solar, hydrogen, and biofuels etc carbon sequestration 3) exploit conventional and cheaper fossil fuels and keep energy bills low at the present, But what of the future? 3

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How and why do charges for fuels vary? e.g. Electricity: - Retail Costs made up of several components 1. The cost of actual generation – depends on fuel used – consequently efficiency e.g. Coal 35 – 38%, Gas 47 – 55% efficient Physically limited by Laws of Thermodynamics – not Technical Limitations fuel cost – UK is now a significant importer, volatile international markets affect prices – before 2004 UK was an exporter Carbon Permit prices – more permits needed for coal 2. A charge for High Voltage Distribution – varies significantly across UK. 3.A charge levied by each of 14 Regional Distribution Network Operators - varies depending on industrial mix in region 4. A charge by Electricity Retailer for actual units consumed 5. A charge for meter reading. Gas: tariffs vary with region 4

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Transmission Demand Charges 5 Distributed Network Ownership Scottish & Southern United Utilities CE Electric UK Western Power Iberdrola UKPower Networks ( Hong Kong Electric) ZoneEnergy Consumed (p/kWh) Current charges as of 1 st April 2011

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2.1 Introduction How is profitability of electricity generation assessed? Clean Spark Spread (CCS) – a measure of profitability of electricity generation by gas. CSS = P E - P G /E G - P CO2 * I G Where P E is wholesale price of electricity P G is wholesale price of gas E G is efficiency of gas generation ~ 50% (range 47 – 55%) P CO2 is Price of EU Emission Permits I G is Emission Intensity of gas = / E G (tCO 2 /MWh) Clean Dark Spread (CDS) – equivalent for coal generation CSS = P E - P C /E C - P CO2 * I C Where P C is wholesale price of gas E C is efficiency of gas generation ~ 38% (range 35 – 38%) I C is Emission Intensity of coal = / E C (tCO 2 /MWh) 6 * Emission Intensity values are typical from IPCC (2006) See paper by Abadie and Chamorro (2008) for more information

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2.1 Introduction Decisions as to whether an energy project is viable are often/ usually made on the basis of an economic analysis alone. However, imperfect analysis of energy issues can be flawed, and give misleading answers on decisions made. Often different researchers will come up with very different answers - WHY???? A project costs: £100 To implement Is this project viable? £20 Annual Saving 1st2nd3rd 4th 5th £20 We will explore many of the issues in this lecture 7

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2.1 Introduction Some concepts for simple cost benefit analyses. Those who have done/are doing Environmental Economics will know some statements below are somewhat simplified, but some important questions are raised in context of Energy. Should traditional ideas about cost benefit analysis – e.g. Pay back time prevail? e.g. Example at NKTs house? 8 Solar PV Solar Thermal How cost effective is Car Insurance???

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2.2 Discount Rate £100 invested in savings giving 5% will generate £105 after 1 year, i.e. 100 * 1.05 = £105 After 2 years the return will be £ i.e. 105 * 1.05 = £ This is the compound interest return on £100 It is not £100 * £100 * 1.05 = £110 which would be the simple interest Similarly after 25 years, compound interest would generate £ compared to £225 from simple interest If one has to borrow money for a project then these values also indicate the total amount to be repaid – i.e. £ and £ respectively – not £110 and £225 This aims to account or the effects of inflation when assessing the economic viability of a project. 9

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2.2 Discount Rate On the other hand what would be the value of £100 saved in 1 years time in present day terms if inflation were 5%?. £ not £95 or £100 saved in 25 years time would be worth £29.53 in todays money Here we are using the present time as a reference and the present value of money to assess future savings. This introduces the term Net Present Value (NPV) to evaluate the present value of future savings. In addition the term Discount Rate is used to deflate future costs/savings to the present day (5% in the example above). 10

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2.2 Discount Rates Supplementary Information: Mathematically, the discount rate is slightly different from the interest rate. In the example given above using 5% £100 in savings would grow to £105 – an increase of £5 in the year. However, £100 in a years time at 5% discount rate would be equivalent to £95.84 or a reduction of £4.16. It is the discount rate that is used to project future cash flows whether these are savings or maintenance costs so that it is in terms of the Net Present Value. Mathematically the discount rate (D) is related to the interest rate (I) as follows: D = I / (1 + I) 11

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2.2 Discount Rates The choice of Discount Rate significantly affects the estimated financial viability of a project. High discount rates favour fossil fuels Medium discount rates favour nuclear power Low/zero discount rates favour conservation/renewables as will be seen later. Even though one might think one is being objective in comparing different energy schemes, the simple selection of one discount rate over another may end up by biasing the result in one direction. 12 However we are jumping ahead – how do we work out the overall NPV of a project?

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2.2 Discount Rates We can assess the economic viability of a project using the discount rate to determine the Net Present Value in two different ways: The Individual discount tabular method (the sledge hammer approach) The Cumulative discount approach using cumulative discount factor tables Example: A conservation project which has a capital cost of £100 but saves £20 p.a. - assume a discount rate, r = 5%: 13

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Year Capital Outlay fuel Saving Discount actor NPV of fuel saving 0£100 1 £ £ £ £ £ £ £ £ £ £ £ £ £ £ Discount Rates: Individual Discount Rate Approach The discount factor of the year n can be computed from the formula: The NPV of a saving (or cost) = (value of saving in the year n) (the discount factor of the year): The NPV reflects the value the fuel saving would have if it was accounted at the present time rather than some years into the future. The cumulative savings over 5 years = £ £ £ £ £15.67 = £86.59 i.e. project would make a loss if equipment only lasted 5 years There would be a profit of £1.51 over 6 years: or £15.73 over 7 years. Frequently projects will also have annual operating costs/maintenance and these should be treated as future costs in a similar manner to the savings.

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Year Capital Outlay fuel Saving Cumulative Discount factor Cumulative NPV of fuel saving 0£100 1 £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ £ Discount Rates The approach shown previously is tedious: often the cumulative discount approach can be used The cumulative discount factor is the sum of the discount factors up to and including the year n. These cumulative factors are available in tables such as the ENV Data Book. The answer is the same as previously but it is much quicker in use as only the life time number of years is needed. Note how critical the choice of the life time of the project is in assessing its viability. Example with 5% discount rate

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How can one calculate cumulative discount rate if tables are not available? 2.2 Discount Rates - summary The Cumulative Discount Factor in year n is the sum of all the discount factors from year 1 to year n And this can be shown to be equal to: The Cumulative NPV to year n is then Annual saving x the Cumulative Discount Factor Remember: If annual saving varies – e.g. because maintenance costs vary, then cumulative approach cannot be used. 16

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2.3 Internal Rate of Return (IRR) For a Project to be viable it must have a positive NPV taking into account capital costs, running costs, savings etc. However, two projects may seem similar, but because of different times of expenditure, one may be preferable to another. Two cases both have capital cost of £100, –Case A has savings of £60, £60, £40, £20, £20 in years 1 – 5 –Case B has savings of £20, £20, £40, £60, £60 – i.e. Same total saving Which is more attractive? 17 Timing 5% discount factor CASE ACASE B Net Cash Flow Present Value Net Cash Flow Present Value Capital Expenditure -£ Year £60.00 £57.14 £20.00 £19.05 Year £60.00 £54.42 £20.00 £18.14 Year £40.00 £34.55 £40.00 £34.55 Year £20.00 £16.45 £60.00 £49.36 Year £20.00 £15.67 £60.00 £47.01 TOTAL £100.00£78.24£100.00£68.12

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2.3 Internal Rate of Return (IRR) The internal Rate of Return IRR is the discount rate at which the NPV becomes zero over the project lifetime. 18 If discount rate < IRR then scheme is profitable – otherwise a loss will ensue. In case A, IRR is ~ 38% In case B it is ~ 22% Thus option A is a better investment and considerably better than normal savings, against which IRR should be compared. See also

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Discount Rates: A cautionary note when assessing different energy projects Discount Rate Net Present Value +ve -ve Capital Costs coal nuclear Renewables/conservation coal nuclear Fossil fuels have relatively low capital costs, but significant fuel costs. NPV significantly affected by discount rate. Nuclear has medium capital costs but low fuel costs. NPV less affected. Renewables/ Conservation usually have high capital costs but low running costs. Little effect on NPV

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Discount Rates: A cautionary note when assessing different energy projects +ve -ve coal nuclear Fossil fuels have lowest NPC at high discount rates therefore more financially attractive Nuclear lowest NPC at medium discount rates. Renewables/ Conservation have lowest NPC at low discount rates. What about negative discount rates? Renewables/conservation Discount Rate Net Present Cost

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2.5 Example 1: An Economic Assessment of loft insulation Roof Area of average house = 49m 2, post-war house with no insulation U-value – a measure of heat loss is ~ 1.6 W o C -1 m -2 The lower the U-value the less heat is lost You will cover U-values later in the course 21 Insulation thickness (mm) U-Value (W o C -1 m -2 ) Heat Loss through 49m 2 roof (W o C -1 ) Annual Heat Loss (GJ) Saving (GJ) % % % % The annual heat loss is the Heat loss multiplied by number of second in a day (86400) multiplied by Degree days (typical average 2200). Then divide by 10 9 to get to GJ

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Price of Energy [British Gas Standard Tariffs on 12/01/2012] Gas: (break point 2680 kWh per year) Tier p/kWh Tier p/kWh [£11.21/GJ] Full Rate Electricity (break point 720 kWh per year) Tier p/kWh Tier p/kWh [£31.82/GJ] Off Peak Electricity 6.919p/kWh [£19.22/GJ] Oil BoilerJuice.Com [12/01/2012] 59.3p per litre equivalent to p per kWh* [£15.93/GJ] [* conversion factors1244 litre/tonne and 46.3 GJ/tonne ] 22 Capital Cost B & Q 12/01/2012 -£3.00 per roll of 200mm thick = £1.84 per sqm. However, cost of 100mm thick was ~ £3.60 per sqm!!! 2.5 Example 1: An Economic Assessment of loft insulation

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23 Capital Costs Case 1 No insulation Case 2 Provide 200 mm insulation – capital cost = 49 * £1.84 = £90 Case 3 Provide 300 mm insulation - capital cost = 49 * £5.44 = £266 Case 4 Existing 100mm insulation Case 5 Top up to 200mm insulation – capital cost = 49 * £3.60 = £176 Case 6 Top up to 300mm insulation – capital cost = 49 * £1.84 = £90 EfficiencyNo Insulation100mm200mm300mm Heat Lost Energy Required (GJ/annum) Electricity100% Gas Condensing90% Oil Non Condensing 70% Energy Requirements From slide 21 Energy Required = Heat Lost / Efficiency 2.5 Example 1: An Economic Assessment of loft insulation

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24 No Insulation100mm200mm300mm Electricity Full rate £474.05£97.67£53.45£35.63 Electricity Off Peak £286.37£59.00£32.29£21.53 Gas Condensing £185.66£38.23£20.96£13.90 Oil Non Condensing £339.21£69.95£38.24£25.49 Annual Energy Running costs using Tier 2 values from slide 22 Annual Savings Initial Status Upgrade to Full Rate Electricity Off Peak Electricity GasOil No insulation 200mm£421£254£165£ mm£439£265£172£ mm 200 mm£44£27£17£ mm£62£37£24£ Example 1: An Economic Assessment of loft insulation

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25 Initial Status Upgrade to Capital Cost Full Rate Electricity Off Peak Electricity GasOil No insulation 200mm£902.6 months4.3 months6.6 months3.6 months 300 mm£ months12.1 months1.5 years10.2 months 100 mm 200 mm£ years6.6 years10.2 years5.6 years 300 mm£901.5 years2.0 years3.7 years2.0 years Simple Payback time – no discounting Note: cost effectiveness is very much less if there is 100mm loft insulation, but grants favour those with no insulation Payback using 5% discount Initial Status Upgrade to Capital Cost Full Rate Electricity Off Peak Electricity GasOil No insulation 200mm£902.7 months4.5 months6.9 months3.8 months 300 mm£ months1.1 years1.7 years0.9 months 100 mm 200 mm£ years8.2 years14.6 years6.7 years 300 mm£901.5 years2.6 years4.2 years2.2 years 2.5 Example 1: An Economic Assessment of loft insulation

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Always add the most insulation possible – incremental upgrades are much less cost effective. Grants are available 50%+, but only if insulation is fitted professionally. Analysis on previous slides is DIY, for which there are usually no grants Example 1: An Economic Assessment of loft insulation 2.6 Example 2: Solar Photovoltaic What is cost of generating electricity– e.g. solar Photovoltaic??? I n is income in year n E is annual energy generated r is discount rate u is unit charge for electricity In absence of maintenance charges, income over life time of n years must >= capital cost C

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Example 2: Solar Photovoltaic Rearranging gives: Solar PV Solar Thermal PV array has a gross output of 1.25 kW and after inverter losses ~ 1.15kW At Load factor of ~ 10% this will generate ~1000 kWh per annum. The capital cost was £6500 What is unit cost which would make scheme profitable over 25 years. For simplicity – ignore maintenance costs. Load factor = Net output over year as % of theoretical generation – see notes on this slide

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Life timeDiscount Rate years2%4%6%8%10% Example 2: Solar Photovoltaic Unit Cost of generating electricity by Solar PV to ensure investment is recouped over life span of project Notice how dependent actual cost o generation is on: Discount rate chosen Life Span of project (note – some of cells on ZICER are having to be replaced after 8 years

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2.6 Project life and Choice of Discount Rate Small Schemes: Exceptional Schemes: with pay back period over 5 years are rarely considered unless the existing equipment is nearing the end of its life and has to be replaced anyway Usually must have pay back in no more than 9-18 months Definitely Cost effective in 2 years Project life for an installation in industry: 29

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2.7 Summary Conclusions The project must have a net positive present value over its life span The project should have the most favorable rate of return when compared to other projects, or to direct investment (i.e. use IRR as an indicator here). If money has to be borrowed to undertake the project, then the rate of return must be greater than the borrowing rate. The choice of specific discount rate can often bias an answer towards a particular option The choice of discount rate and life span of a project affects estimates of future costs of generating electricity Other considerations are also relevant – What price SECURITY of SUPPLY?? An Economic assessment should be only one of several considerations when assessing a project 30

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