Local Solar PV Systems Update Promoting Research and Education for - - PowerPoint PPT Presentation

Local Solar PV Systems Update

Promoting Research and Education for Alaskans in Sustainable Development

acat.org

Getting to Net Zero Energy

26kwh $1800 NZE 0 kwh $68 Step 5: Solar Panels Step 1: Phantom Loads 26kwh $1800 NZE 0 kwh $68 24kwh $1684 26kwh $1800 NZE 0 kwh $68 17kwh $1201 Step 2: Lighting 26kwh $1800 NZE 0 kwh $68 11kwh $742 Step 3: Appliances 26kwh $1800 NZE 0 kwh $68 7kwh $554 Step 4: HVAC Equipment

PASSIVE SOLAR vs. HEATING DEGREE DAYS

See UAF Co‐Ops Alaska Solar Guide.

Solar – PV Watts2

Solar – PV Watts2

Solar PV seasonal site angles

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 12‐15 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

Solar PV Array

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

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: 12‐15 years, DIY

5% Return on Investment

• Special Notes:

Cleaning is important, 3‐4x per year. Love their setup, glad they did it.

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

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
• f your utility’s requirements for permits.

Delayed interconnect 4 months. Snow cleared at 45 deg with some sun.

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

Agate Solar PV Array ‐ 48kw

• System Size: 8 x 250w panels = 2kw
• System Type: Central Inverter
• Mounting: Building mount, 45&60 deg.
• 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

• 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

6 KW array 6 KW array

Economic Assessment

ACAT Annual Meeting

• Nov. 12, 2016

Masteller PV System

System Info

• 3705 kW rated power
• 13 285‐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

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.

Estimating Energy Production

All methods require estimate of energy produced (kWh) over some period of time

Estimating Annual Production

Using online PVWatts calculator (pvwatts.nrel.gov/)

Data Inputs

• 3705 Watt array at 60‐degree tilt angle, true south
• rientation
• Using Palmer airport solar insolation data
• Price of kWh from utility ($0.19)

Estimated annual production = 3,145 kWh Estimated annual energy value = $600

Annual Production – PVWatts

491 421 347 262

Actual Production

Method 1 ‐ Cost of Electricity Comparison

Compare, over 30 yrs:

• cost of kWh from PV system

to

• cost from conventional source (e.g. utility)

Economic Analysis

Cost of Electricity Comparison

3.705 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

Economic Analysis – Method 1

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

Economic Analysis

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 = 0.111
• 0.111 x 100 = 11.1 percent ROI

Economic Analysis – Method 2

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…

Economic Analysis

Energy Inflation Rate

Example ‐ Cook Inlet Natural Gas

20‐year period 1993‐2012 150% increase total Average 7.5% per year 6‐year period 2004‐2009 140% increase total Average 23% per year

Cost depends on many factors, including

• Size of system
• Complexity
• Using installer? DIY?
• Distance installer must travel
• Type of installation
• Difficulty of installation
• Etc.

Review ‐ Reminder

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

Economic Analysis

Incentives

Federal, state and local incentives can make a HUGE difference If you want to know incentives:

• www.dsireusa.org
• Database of State Incentives for Renewables and

Efficiency What’s OUR role in incentives?? Policy‐making??

Economic Analysis

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 = $0.0825 / kwh
• Power purchased from grid = $0.11455 / kwh plus tariffs

$0.191174 / kwh with tariffs

• Difference in bought – sold = $0.10 /kwh

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.

• MEA Monthly fee = $5.65
• Annually = $67.80

26kwh $1800 NZE 0 kwh $68

PATH TO NET ZERO WORKSHOP SERIES

Non-profit education outreach for Net Zero Energy Register Online: www.ACAT.org Full Day Workshops

• $80 -160 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