Residential Solar Power in Midwest

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Residential Solar Power in Midwest Powered By Docstoc
					Residential Solar Power in
        Midwest

                        Patrick Chapman
                                 Associate Professor
                                 University of Illinois at
                                 Urbana-Champaign




     February 4, 2008
Example: Illinois Energy Picture

   Dominated by nuclear, coal
   Some wind power
   Solar power << 1%

   New Illinois Power Agency reportedly:
    –   Requires 25% of Illinois energy from renewable
        sources by 2025
    –   Requires 2% by June 1, 2008
    –   75% of this must be wind
    –   Governs net metering and other aspects of power
Illinois Energy
2006 data:

5th in population
10.37¢/kWh residential
18 GWh of generation
17.3 GWh =coal +
nuke
Illinois Solar Map




~ 4000 Wh/m2 per
day

Source: DOE
More-Detailed Maps




Provided by Angus Rockett, Univ. of Illinois
   Growth Internationally




Chart from US Photovoltaic Industry Roadmap (NREL, 2001).
PVWatts (NREL)

   Based on collected solar data (only select
    years)
   More reliable that clear-sky calculations
   Available for certain sites
   Specifications
    –   Tilt = latitude
    –   Azimuth = true south
    –   0.77 derating factor


   “Solar Advisor Model” from NREL
PV Economic Viability

   Varies from place to place
    –   Solar radiation
    –   Cloud cover
    –   Price of electricity
    –   Real-time pricing vs. fixed pricing
    –   Installation costs (labor)
    –   Demand for modules
    –   Availability of installers
    –   Rebates and incentives
Calculations for Select Sites

   For a 1-kW array
    –   Rockford: 1212 kWh/yr ($0.089/kWh)
    –   Springfield: 1281 kWh/yr
            Quick multiplier: 1250 kWh/yr/kW-installed
    –   Long Beach: 1449 kWh/yr ($0.136/kWh)
    –   Tucson: 1617 kWh/yr

    –   Portland, ME: 1280 kWh/yr ($0.128/kWh)


   National average in 2007: $0.097/kWh (all
    sectors) – Hawaii is about $0.21/kWh
Specifications
   Tilt
     –   Tilt = latitude good rule of thumb
     –   Slightly shallower is optimal
              Diffuse and reflected light are significant
   Azimuth
     –   True south optimal
     –   +/- 15 degrees OK
     –   Watch out for magnetic south
   Derating – 77% typical starting point
     –   PV module hero numbers (few %, temperature)
     –   Inverter efficiency (94%)
     –   Wires (98%-99%)
     –   Dirt, aging (few %)
     –   Mismatches (few %)
PV Module Efficiency

   Ratio of electrical power out to sunlight power
    in
   Notice, not included in specifications
    –   Somewhat overrated figure of merit
    –   Higher efficiency = smaller space
    –   Higher efficiency = higher cost (usually)
   Key figure of merit is $/W or $/Wh
    –   Aesthetics also important
   10% to 14% typical for silicon
    –   22% for SunPower modules
Illinois Rebate Programs

   State rebate program
    –   30% of project costs
    –   Maxes out at $10,000 <<< Note, taxable grant
    –   Limited budget (ran out of money last FY)
    –   Straightforward application, but takes time/care
   Federal tax credit
    –   30% of project costs
    –   Maxes out at $2,000
   Commercial – similar programs
   Illinois Clean Energy Community Foundation
    –   Other, larger scale projects
Case Study in Urbana

   2.87-kW array
   Based on Springfield data
    –   3669 kWh/yr
    –   30-degree tilt (pitch 7’x12’)
    –   15 degrees west of south
    –   0.77 derating (conservative)
   SunPower system
    –   14 205-watt modules
    –   3300-watt inverter
Photos Case Study

   Initial work
More Photos

   Racking
More Photos

   Modules
More Photos (Inverter and Monitor)

   Inverter and Monitor
Finished Project
Connecting to Ameren

   Somewhat complicated, but cooperative
   Register with FERC as QF
    –   Qualifying Facility
    –   Self-certify – not difficult, just annoying
   Submit schematic and specs to Ameren
    –   Pay $100
    –   Their engineer will approve drawings
   Sign connection agreement
    –   Can request waivers on insurance, etc.
   Sign QF Rider agreement
    –   Pick real-time pricing or normal rates ($333 meter)
Example Schematic
Real-Time Pricing

   Price peaks more/less with sun
Pricing

   Smart Power Pricing program
    –   Administered by CNT
    –   $2.25 per month participation
    –   Get wholesale price (Ameren providing wires, this is
        fair)
   Recent legislation allows net metering
    –   Get the retail price
    –   Eliminate Smart Power Pricing?
   The Public Utilities Act is amended by adding 5
    Section 16-107.5 as follows…
    –   Ameren to provide free meter… (?)
Sample Billing (9/24-10/23)
            Usage (kWh)          PSP Billing (net
9
8                                energy consumed)
7
6
5
4                                Total Energy: 861
3
2                                kWh
1
0
                                 Total Price: $51.37
      1
     26
     51
     76
    101
    126
    151
    176
    201
    226
    251
    276
    301
    326
    351
    376
    401
    426
    451
    476
    501
    526
    551
    576
    601
    626
    651
    676
                                  = $0.0596/kWh
    This is the energy             Price ($/kWh)
                          0.8
    supply charge.        0.7

    Distribution (“the    0.6
                          0.5               $0.71 at noon,
    wires”) costs         0.4
                          0.3
                                            10/8
    $0.0245/kWh           0.2
                          0.1
                            0

    Total = $0.084/kWh
                                   1
                                  27
                                  53
                                  79
                                 105
                                 131
                                 157
                                 183
                                 209
                                 235
                                 261
                                 287
                                 313
                                 339
                                 365
                                 391
                                 417
                                 443
                                 469
                                 495
                                 521
                                 547
                                 573
                                 599
                                 625
                                 651
                                 677
                          -0.1
Sample Days

    0.8


    0.7


    0.6


    0.5


    0.4                                                                    8-Oct
                                                                           1-Oct
    0.3


    0.2


    0.1


     0
          1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24




Saving $20 to $40 per month compared to flat rate
                                                       




       -2
                   -1
                                     0




            -1.5
                        -0.5




-2.5
                                 1
                                17
                                33
                                49
                                65
                                81
                                97
                               113
                               129
                                                       -133 kWh


                               145
                               161
                               177
                               193
                               209
                               225
                               241
                               257
                               273
                               289
                               305
                               321
                               337
                                                                  Generated Power




                               353
                               369
                               385
                               401
                               417
                                     Generated power




                               433
                               449
                               465
                               481
                               497
                               513
                               529
                               545
                               561
                               577
                               593
                               609
                               625
                               641
                               657
                               673
                               689
One Day Example (kW-hr vs. hr)
                              8-Oct
  0

-0.1
       1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24   Peaks nearly line
-0.2
                                                                        up, maximizing the
-0.3

-0.4
                                                                        benefit
-0.5

-0.6

-0.7
                                                                        Note this is net
-0.8                                                                    generation
                         Oct 8 Prices
0.8                                                                     On “negative load”
0.7
0.6                                                                     generation, effectively
0.5
0.4
                                                                        get the retail price
0.3
0.2
0.1
 0
       1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Economics
   Upfront cost, about
    $27,000
    –   $9 per peak watt, installed
   Breakdown in cost per
    watt
    –   $4.50 for PV modules
    –   $1.00 for inverter
    –   $3.50 for installer labor
        and markup
   Rebates
    –   $8,100 for IL (took eight
        months to receive check)
    –   $2,000 for Federal
   Net cost: $16,900
“Investment” Analysis

   At $0.10/kWh = $366.90/yr yield
   Simple payback, a mere 46 years!

   This is unfair to PV
    –   (PV held to near impossible standard)


   Need to look at
    –   Amortized cost (buying all power upfront)
    –   Equity
    –   Increases in electricity prices (real time price?)
    –   Environmental advantages
More Econ

   Realtors estimate $1,000 savings = $20,000
    equity
    –   $366.90  $7,338 in equity, and rising
    –   Net out-of-pocket = $9,562
    –   Assumes there is a willing buyer
   4% rise in rates = 50% increase in prices in 10
    years – effects payback and equity
More Econ

   As part of home mortgage
    –   6.75% (30-yr) mortgage, interest is initially
        $95/month ($66.50 after taxes)
    –   $33.58 in energy per month – about $33 per month
        deficit
   Year 15, prices go up, interest is down
    –   $55/month savings, $49/month interest
    –   Equity is $13,200, not much less than the $16,900
        upfront cost
Other “investments”

   A 4% CD would have generated $13,536 in
    income on $16,900 principle
    –   After taxes, this is ~$10,000 yield
   15 years of electric savings lost
    –   About $500 per year on average
    –   ~$6,000 in 15 years of savings lost
    –   Net yield on the (CD – electricity) is $4,000
   This is about an $8,000 deficit
    –   This is about $44/month average “luxury” price for
        the electricity, or about $0.15/kWh
    –   Gets better with more time
For Comparison

   Other things that cost $17,000…
    –   BMW 500 over a Toyota Prius
    –   Extra bedroom
    –   One semester out-of-state tuition at Illinois
    –   Etc.
   Conservative?
    –   Rates may go up faster
    –   PV costs will go down
    –   Home interest rates lower
   Unconversative?
    –   Repairs, maintenance, other risks
Cost Drivers and Trends
   Manufacturing costs for PV modules going down
     –   Prices still high due to shortage
   Competition in China coming fast
   Must achieve $3/Wp installed cost and 25 year warranty to have
    grid parity


                                     PV Module Costs




Source: Evergreen Solar
2007 Solar Decathlon

   Dept. of Energy Sponsored Event
   Large national media attention – National Mall
   Draw awareness to solar power

   20 universities to build solar houses
   10 events (with overall prizes)
Contests

   Architecture (200 pts)
   Engineering (150 pts)
   Marketability (150 pts)
   Communications (100 pts)
   Comfort Zone, Getting Around, Hot
    Water, Lighting, Appliances (100 pts)
   Energy Balance (100 pts)
Univ. of Illinois Finish

   9th overall
   1st in
    –   Comfort Zone (best passive solar and HVAC
        design)
    –   Marketability (very affordable, ordinary building
        materials, expandable)
   Homes limited to 800 sq. ft.
   Multitude of other limitations and rules

   Accepted for 2009 competition
Final Illinois House on the Mall
    ($450k)




              Source: SD07 photos from solardecathlon.org
Winning Overall House

   Darmstadt ($2M)
Other Remarkable Houses

   Georgia Tech, Missouri-Rolla
Other Remarkable Houses, cont’d

   Santa Clara, Lawrence Tech
Passive Home Design for 2009
   Passive heating and
    cooling is largely
    feasible in the Midwest
   PassivHaus Institute
    US (PHIUS) is located
    in Urbana
    –   Superinsulated homes
        (1200 sq. ft.)
    –   No central air
        conditioning of furnace
    –   Earth-tube intake
    –   Southern exposure
        adequate for PV – a 1-
        kW system = zero net
                                  Source: e-colab.org
        energy
Summary

   PV taking off but still just off the ground
    –   “normal” people now taking notice
   Midwest is a poor economic case
   Environmental improvement is worth?

   Still makes most sense to do conventional
    efficiency improvements first
    –   Insulation, sealing
    –   Compact fluorescent lighting
    –   Better HVAC (geothermal, etc)