Photovoltaic

Association of Energy Engineers -NE A discussion about Solar 9/10/2014 Agenda

. PV system overview & components

. National Grid’s role in integrating Photovoltaic

. The photovoltaic market , its benefits, and opportunities

. Questions

2 What is Photovoltaics? – MiniHistory

Edmund Becquerel, a French physicist, discovered that 1830 certain materials produced a current in 1839.

Prior to 1918 selenium was used in solar applications for its photoconductivity. Then a process to create single- 1900 crystal silicon was developed. (The vast majority of PV panels use silicon today!)

PV started to make its way into spacecraft design in the 1970 1960s

National Grid deployed solar technology in the 1980s, launching solar installations on over 30 homes and businesses in Gardner, MA and app.75 kW installation at Beverly High School in Beverly, MA.

Current day it’s a new leaf of life, to live sustainably and 2013 use green energy is the transitioning mentality. Solar is used at the commercial level by utilities and residential level by many eager incentivized homeowners.

3 What is Photovoltaics? Basic PV Cell Operation

Circuit diagram attained from National Instruments (NI.com) Cell VI curve attained from boatdesign.net System Overview

There are differences between large commercial PV arrays and smaller residential PV arrays. Residential System

. Smaller solar systems will be encountered more often . Usually PV panels are roof- mounted which may make responding to emergency situations challenging . System components include: . Panels (Array) . Combiner box (Not shown) . Inverter A basic residential PV system . AC power disconnect (Panel) Holt, Mike. Residential PV System Scope. Digital image. Mike Holt Enterprises, Inc. Charles Michael Holt, 11 Nov. 2011. Web. 22 July 2013. . Storage batteries (Not shown)

6 Commercial System

. Large solar arrays typically have a power capacity of 150 kilowatts (kW) to 100 megawatts (MW) . These arrays will have: . Combiner boxes for multiple strings of PV panels . DC power disconnects . Weather station . System Rack . Ballasts . 1 or more large inverter . High voltage AC power disconnect

National Grid’s 1.25 MW solar installation in Dorchester

7 System Components

A Solectria SGI 500W inverter at NG’s Dorchester solar site.

Component identification is essential for ensuring safety and preventing health hazards. Panels – Modules

. Solar Modules are made up of silicon cells, a highly abundant element on earth . Monocrystalline production is old and inefficient . Polycrystalline production is more efficient and more current than monocrystalline production . These panels will be framed (aluminum or other lightweight/ durable metal) Installing 210 Watt polycrystalline modules at National Grid’s NEDC site.

9 Panels – Shingles

. Another way to produce solar cells is with amorphous silicon. . To create these panels, silicon is vaporized and deposited on a flexible surface. . The advantage of this is the variety of application enabled by the flexibility of the .

NREL. 17W Solar Integrated Roofing Shingles. Digital image. National Renewable Energy Laboratory. WebDAM, n.d. Web. 22 July 2013.

NREL. Roofing Shingles. Digital image. National Renewable Energy Laboratory. WebDAM, n.d. Web. 22 July 2013

10 Panels - Measurement Devices

. For data collection purposes, measurement devices may be attached to modules. . Module Surface Temperature Sensor - measures temperature of module . Pyranometer – measures solar irradiance (amount of radiation per unit area)

11 Combiner Boxes

. Each string of modules will have a combiner box. . This is a central place where all the modules on that string connect. . Small arrays will have one combiner box while large arrays will have many.

12 DC disconnects

. An Important feature of a PV system are the disconnects . The DC disconnects are usually located near the panels, after the combiner boxes. . NOTE: Even after panels are disconnected, electricity is still generated when the panels are exposed to light.

13 System Rack

The rack provides the mounting structure for the panels and other PV instruments

14 Ballasts

. Some PV systems are not mounted directly to the surface they are on. Instead, heavy footings made of rubber, cement, or other durable material is provided to secure the rack and panels. These can weight 300 Ib each. . Ballasts are used on ground or flat roofs

15 Inverters

. The inverters will convert DC to AC so the solar system can tie to the grid or supply power to a household. . These units contain high voltages. . Caution: These contain large capacitors that will continue to hold a lethal charge even after being disconnected from the grid side and panel side

16 AC disconnects

An AC disconnect is the “main power” shut off in a PV system. This is where the solar array will connect to the grid.

17 Storage Batteries

. Storage batteries are becoming practical for commercial solar applications . Currently, most battery NREL. Solar Battery System . Digital image. National Renewable Energy systems will be found in Laboratory. WebDAM, n.d. Web. 22 July 2013. residential applications. . During times of overcast or at night the PV system will use battery power to continue providing electricity to the home.

NREL. Solar Battery System 2 . Digital image. National Renewable Energy Laboratory. WebDAM, n.d. Web. 22 July 2013.

18 Why does National Grid invest in PV? Why is National Grid doing PV?

• Since 2009, National Grid has integrated over 300 MW of third party- owned distributed generation facilities within its service territory.

• National Grid is looking to integrate a greater number of projects with higher benefits to customers, developers and the electric distribution system, especially given the Commonwealth’s new goal of 1,600 MW of solar by 2020, set by Governor Deval Patrick.

• Installing solar generation in pre-selected areas will enable the company to experiment with new tools and unlock technical challenges. Which National Grid will share with the entire energy community, assisting toward the Commonwealth’s clean energy goals.

20 The Green Communities Act (GCA)

. The Green Communities Act was passed in MA in 2008 . Allowed investor owned utilities to own, operate and recover the cost of 50 MW of solar . Grow the solar industry and stimulate broader economic growth . Advance the market to lower the cost of renewables . Achieve 250 MW of installations by 2017 . Meet at least 20% of the states electric load by the year 2020 through renewable and alternative energy generation

21 Company Owned Solar

. Phase I Solar . Constructed 5MW’s of PV . Five sites: Dorchester, Haverhill, Everett, Revere and Sutton . Production and more facts can be found at: https://www.nationalgridus.com/masselectric/solar/

. Phase II Solar . DPU approved June 28, 2014.

Objective: . Purchase 20 MW of turn-key solar sites . Implement advanced inverters . Learn more about impacts of solar on areas with: . High PV Penetration . Lightly Loaded feeders . Heavy Loaded Feeders

22 National Grid Solar Phase I

. National Grid owns the systems. . Energy (kWh) and Solar renewable energy certificates (SRECs) are sold to the market at prevailing market prices and are used to offset the cost of the installation. . Project is financed by National Grid’s customers in MA through an approved monthly fee added to the electric bills.

23 Dorchester - 1,250 kW

24 Waltham - 225 kW

25 Everett – 605 kW

26 Haverhill – 1016 kW

27 Revere – 750 kW

28 National Grid Solar Phase II

In progress… Expected Completion: June 30th, 2014

29 The Photovoltaic Market The Benefits of PV

Known Benefits . Reduced carbon footprint . Reduced fossil fuel consumption by conventional power plants . Reduced energy bills for customers . Providing jobs

31 The Benefits of PV

Solar Emissions Offset of National Grid Sites

32 The Benefits of PV

Potential Benefits . Reducing the effects of outages . Reducing utility system and customer costs . Grid support through advanced inverter technology . Power quality . Reliability

33 Economics of Solar Generation

Dependent on . scale, solar variability, intermittency, carbon displacement

. ancillary services vs. displacement of other type of generation (carbon intense)

. Locational Marginal prices and solar power production

34 Economic benefits

. Employment opportunity

. Investment opportunities

. New sources of income for property owners

35 Capital Costs

Courtesy of NREL

36 Expected O&M

Courtesy of NREL

37 Useful Life

Courtesy of NREL

38 Solar in the U.S.

39 Solar generation in New England

Is PV feasible in New England?

How does it compare with other locations in the US?

Location Capacity Factor Boston, MA 14.2% Lynchburg, VA 15.3% Boulder, CO 16.7% Albuquerque, NM 19.2% Flagstaff, AR 18.4% San Francisco, CA 16.5% San Diego, CA 17.1% * Values from NREL’s PVwatts

40 Solar Renewable Energy Credits (SRECs)

-- SRECs are an opportunity for solar plants to create income --

A SREC is attained for each MWh produced by a solar renewable energy . Want to increase plant efficiency and decrease power consumption . Can be worth significantly more than LMP . In rare cases, LMP goes to 0, or even negative . Renewables stay on as long LMP > REC price Companies create renewable portfolios . Some states mandate Renewable Portfolio Standards (RPS)

Put into RPS Energy Accounted RECs Issued by owner or Created for by ISO sold Investment Tax Credit (ITC)

. A Federal policy created by the Energy Policy Act of 2005 to encourage renewable energy growth . Solar developers receive a 30% tax credit on residential and commercial PV systems. . Currently, the ITC will continue through December 31,2016

42 Financing – PPA

-- Power Purchase agreement –

. No construction/installation cost for customer

. Customer pays a specific rate for electricity generated

. At end of term property owner extends contract or buys the PV system

43 Financing PV – Lease

-- Lease -- . Customer signs a tradition lease and pays for the use of the system . Allows for minimal to no up-front costs . Eventual ownership

44 Investment based on tariffs rather than contracts . Long term contracts are not always the best answers . Rhode Island General Assembly introduced approved new renewable energy bill H-7727 and S-2690 . Renewable energy developers are guaranteed a long term tariff instead of a contract

45 Net Metering

. Gaining popularity as distributed generation (DG) grows . Allows the tracking of imported and exported electricity for finances. . If customer generates more energy than consumed, an electricity credit will be issued.

46 Virtual (or remote) Metering

Allows customers with net metered PV to allocate net metering credits to other NG accounts within the ISO-NE load zone . Helps customers who are interested in PV . May not be best fit for customers without DG

47 Challenges to Large Scale PV Generation

. Peak power output around midday – summer peak power usage is early evening . Land availability – clearing woodland for solar panels? . Unknown effects of large scale use of renewable energy on the Grid – renewable energy sources are not predictable.

48 Resiliency without battery storage

. PV is subject to: . Potential problems: . Weather intermittency . Slow transients that . Peak load demand can cause voltage swings on feeders . Night time . Peak load demand will not be alleviated if maximum generation azimuth is used . Base load PPs cannot quickly change with solar generation variance

49 Resiliency with battery storage

. Possible solution to: . Voltage fluctuations . Maximum generation and peak load demand relief trade off . Night time generation

Courtesy of NREL 50 Looking to install a PV systems at a facility?

. Fixed PPA VS variable PPA. What is the risk? . Guaranteed output? . Is the assumed utility rate increase per year for the life of the contract valid? . Is the energy degradation factor of the solar generation over the life of the system reasonable? . Is the fixed PPA $/ kWh reasonable? . Robust O&M plans? . At the end of contract term, what are the costs associated with dismantling, owning, or extending the contract? . Is there a lease payment for the property and is fair?

51 Questions

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