Local Solar PV Systems Update

Transcription

1 Local Solar PV Systems Update Promoting Research and Education for Alaskans in Sustainable Development acat.org

2 Getting to Net Zero Energy Step 1: Phantom Loads Step 2: Lighting Step 3: Appliances Step 4: HVAC Equipment Step 5: Solar Panels 26kwh $ kwh $ kwh $ kwh $ kwh $ kwh $ kwh $ kwh $742 7kwh $554 0 kwh $68 NZE 0 kwh $68 NZE 0 kwh $68 NZE 0 kwh $68 NZE 0 kwh $68 NZE

3 PASSIVE SOLAR vs. HEATING DEGREE DAYS See UAF Co Ops Alaska Solar Guide.

4 Solar PV Watts2

5 Solar PV Watts2

6 Solar PV seasonal site angles

7 Jason s Solar PV Array 3.65kw System Size: 13 x 280w panels = 3.65kw System Type: Central Inverter (Power Optimizers to control voltage) Mounting: Roof, 60&30 degrees Annual kwh: 2890kwh (estimated) Installed Cost: $7000 / $4900 w/ Credit Payback years, DIY with Tax Credit 5% (simple) Return on Investment Special Notes: NZE for electrical only for year? Frost still sticks at 60 degrees Edge of cloud effect

8 Solar PV Array At the end of the year, any remaining additional production is paid out for a zero balance.

9 Paul& Julie s Solar PV Array 3kw System Size: 12 x 255w panels = 3kw System Type: Central inverters Mounting: Ground racking, 45 degrees Unistrut racking Annual kwh: 2200kwh Installed Cost: $7,000 / $4,900 w/ Credit Payback: years, DIY 5% Return on Investment Special Notes: Cleaning is important, 3 4x per year. Love their setup, glad they did it.

10 Art&Danielle s Solar Array 3kw System Size: 12 x 255w panels = 3kw System Type: Central inverter Mounting: Ground racking, 45 degrees Unistrut racking Annual kwh: 2500kwh Installed Cost: $5,500 / $3850 w/ Credit Payback: 8 12 years, DIY 5% Return on Investment Special Notes: Less surrounding trees and shading Shorter distance to electrical panel

11 Alan s Solar PV Array 2.85kw System Size: 10 x 285w panels = 2.85kw System Type: Enphase microinverters Mounting: Roof racking, 45 degrees Annual kwh: 2500kwh (estimated) Installed Cost: $12,100 / $8,470 w/ Credit Payback: 20 years 5.2% Return on Investment Special Notes: Make sure you are aware of your utility s requirements for permits. Delayed interconnect 4 months. Snow cleared at 45 deg with some sun.

12 Palmer Solar PV Array 2kw System Size: 8 x 250w panels = 2kw System Type: Enphase microinverters Mounting: Ground racking, 45 degrees Annual kwh: 2000kwh Installed Cost: $5,000 / $3,500 w/ Credit Payback: 20 years 5.2% Return on Investment Special Notes: Originally had Enphase microinverters but problems with cold 20F. Sent 1740 kwh to grid Total used in house 1190 kwh Used 930 kwh from grid Produced extra from March - October

13 Agate Solar PV Array 48kw System Size: 8 x 250w panels = 2kw System Type: Central Inverter Mounting: Building mount, 45&60 deg. 6 KW array Annual kwh: 12,000kwh (estimated) Installed Cost: $36,000/$25,000 w. Credit $3/watt w/ local labor Payback: 11 years 9% Return on Investment 6 KW array Special Notes: Powering multiple buildings 3 houses and 2 apartment buildings Meter buildings separately, bill combined Electric bill ~ $94 for all 5 buildings 3/2015 Bills show credit for 2 apartments in March

14 Economic Assessment Masteller PV System ACAT Annual Meeting Nov. 12, 2016

15 System Info 3705 kw rated power watt panels with DC power optimizers 60 deg tilt angle; oriented to true south 5000W string inverter IronRidge racking $7700 total cost = $2.08/watt After 30% tax credit; system cost $5400

16 Economic Analysis Two relatively simple methods: Cost of Electricity Comparison Return on Investment Another more complicated method Total Cost of Ownership Typically used for large investments Includes time value of money, loan interest, energy inflation rates, etc.

17 Estimating Energy Production All methods require estimate of energy produced (kwh) over some period of time

18 Estimating Annual Production Using online PVWatts calculator (pvwatts.nrel.gov/) Data Inputs 3705 Watt array at 60 degree tilt angle, true south orientation Using Palmer airport solar insolation data Price of kwh from utility ($0.19) Estimated annual production = 3,145 kwh Estimated annual energy value = $600

19 Annual Production PVWatts Actual Production

20 Economic Analysis Method 1 Cost of Electricity Comparison Compare, over 30 yrs: cost of kwh from PV system to cost from conventional source (e.g. utility)

21 Economic Analysis Method 1 Cost of Electricity Comparison kw system near Palmer; producing 3145 kwh/year; system cost after tax credit $5400 Now, to compare with buying from utility: Calculate total energy value over 30 yrs: 3145 kwh/year for 30 years = 94,350 kwh 94,350 kwh x $0.19/kWh = $17,926 over 30 years

22 Economic Analysis Method 2 Return on Investment Another relatively simple method An estimate of the rate of return on your investment Savings generated by investment in RE system are expressed as percentage of investment

23 Economic Analysis Method 2 Return on Investment Divide annual dollar value of energy generated by total system cost Annual Electricity value: 3145 kwh/year x $0.19/kWh = $597/year Rounding: $600 divided by $5,400 = x 100 = 11.1 percent ROI

24 Economic Analysis Weaknesses Cost of Electricity and ROI Methods These simple tools typically ignore: Interest payments on loans Rising cost of electricity (aka energy inflation rate ) Different rate you pay for kwh versus what you get paid when it goes on grid Opportunity costs lost income from other things you could have done with the money

25 Energy Inflation Rate Example Cook Inlet Natural Gas 20 year period % increase total Average 7.5% per year 6 year period % increase total Average 23% per year

26 Review Reminder Cost depends on many factors, including Size of system Complexity Using installer? DIY? Distance installer must travel Type of installation Difficulty of installation Etc.

27 Economic Analysis Misleading Method Simple Payback Common term, and frequent question Defined time needed to pay back system cost Easy to understand, but misleading (Chiras) Do we routinely apply this concept to anything else? Any energy related device in our home? Simple payback more appropriate for energy conservation/efficiency measures

28 Economic Analysis Incentives Federal, state and local incentives can make a HUGE difference If you want to know incentives: Database of State Incentives for Renewables and Efficiency What s OUR role in incentives?? Policy making??

29 NET ZERO ELECTRICAL METERING NET METERING energy produced and energy used are measured at the building location. Equal utility rates? MEA Rates for power purchase vary quarterly. Power sold back into grid = $ / kwh Power purchased from grid = $ / kwh plus tariffs $ / kwh with tariffs Difference in bought sold = $0.10 /kwh 26kwh $1800 What does this mean? If you are using the grid as a battery and trying to pay for your winter/evening energy usage with summer/daytime production, you ll need to produce more than energy than you use. FEES AND TARIFFS utility providers have fees and tariffs isolated from actual usage cost. Even if you make as much energy as you use, you will still have a utility bill. 0 kwh $68 NZE MEA Monthly fee = $5.65 Annually = $67.80

30 PATH TO NET ZERO WORKSHOP SERIES Non-profit education outreach for Net Zero Energy Register Online: Full Day Workshops $ General Admission $40-80 Students and members $225+ w/ Continuing Ed. Certificate Lectures, Shorter Workshops $20 General Admission $10 Student* $75 w/ Cont. Ed. Certificate *Scholarships Available