Alternative electrical energy sources for Maine

I

ALTERNATIVE ELECTRICAL ENERGY SOURCES FOR MAINE SUMMARY REPORT

W.J. Jones M. Ruane

MIT Energy Laboratory Report No. MIT-EL 77-010 December 1977

ALTERNATIVE ELECTRICAL ENERGY SOURCES FOR MAINE

W.J. Jones M. Ruane

SUMMARY REPORT

This report, prepared for the Central Maine Power Company, presents a comparative discussion of twelve technologies which were evaluated as possible alternatives to the construction of a 600 MWe coal-fired gener-ating plant.

The evaluations are published as appendices, each devoted to a spe-cific technology.

Acknowledgments

Numerous people shared reports and data with us and provided

comments on the draft material. We hope that everyone has been

acknowledged through the references in the technical sections,

but if we missed anyone, thank you!

Ms. Alice Sanderson patiently weathered out many drafts and

prepared the final document with the assistance of Ms. Dorothy

Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Appendix I Appendix J Appendix K Appendix L

Conversion of Biomass - C. Glaser, M. Ruane

Conservation - P. Carpenter, W.J. Jones, S. Raskin, R. Tabors

Geothermal Energy Conversion - A. Waterflow

Ocean Thermal Energy Conversion - M. Ruane

Fuel Cells - W.J. Jones

Solar Energy Conversion - J. Geary, W.J. Jones

Conversion of Solid Wastes - M. Ruane

Storage of Energy - M. Ruane

Wave Energy Conversion - J. Mays

Ocean and Riverine Current Energy Conversion - J. Mays

Wind Energy Conversion - T. Labuszewski

Environmental Impacts - J. Gruhl

Initial literature reviews and drafts of the various technical appendices were prepared by the persons listed.

Preface

The Energy Laboratory of the Mass. Inst. of Tech. was retained by the Central Maine Power Company to evaluate several technologies as possible alternatives to the construction of Sears Island #1 (a 600 MWe coal fired generating plant scheduled for startup in

1986).

The assessments were made on the basis that a technology should be:

1) an alternative to a base -load electric

power generation facility. Base - load is

defined as ability to furnish up to a rated

capacity output for 6570 hours per year.

2) not restricted to a single plant. It

may be several plants within the state of Maine. The combined output, when viewed in isolation, must be a separate, "stand-alone" source of power.

LIST OF TABLES

Table Page

1.1 Technologies Considered 10

2.1 Components of Alternatives 22

2.2 Capacities and Annual Energies from Alternative

Technologies 25

3.1 Summary of Environmental Impacts of Alternative

Technologies 29

4.1 Special Requirements for Alternative Technologies 32

5.1 Levelized Fixed Charge Rate Assumptions 35

5.2 Optimistic Electricity Costs from Alternative

ALTERNATIVE ELECTRICAL ENERGY

SOURCES FOR MAINE

Page

Conclusions 6

1.0 Introduction 10

1.1 Scope of the Study 10

1.2 Methodology 11

1.3 Discussion 12

1.4 Caveats 14

2.0 Status of Technological Development 17

2.1 Principles of Operation 17 2.2 Components of Alternatives 21 2.3 Technical "Quantification" 21 3.0 Environmental Effects 27 4.0 Applicability to Maine 30 4.1 Special Requirements 31

4.2 Estimates of Energy and Capacity 31

5.0 Economics 33

5.1 Economic Assumptions 33

5.2 Cost of Electricity 36

LIST OF FIGURES

Page

1.1 Projected Electric Sales for Central Maine Power 13 Figure

Conclusions

A) The alternative technologies to a coal-fired steam/electric

plant considered in this report cannot be relied upon to supply the

expected increase in demand for electricity in Maine by 1986.

Tech-nical, regulatory, and institutional limitations, and the lack of

com-mercial experience indicate that they could not reliably be expected

to supply the power and energy of the proposed plant.

B) Several of the alternative technologies (biomass,

conserva-tion, solar space and hot water heating, solid waste conversion,

sto-rage, and wind) appear to offer some potential of increased energy

ef-ficiency and renewable indigenous energy supplies with acceptable

re-duced environmental impacts. These near-term technologies could begin

to contribute to Maine's energy supply between now and 1986. They

should be examined further and encouraged to determine if they are

en-vironmentally and economically desirable.

C) Other alternative technologies (central station solar

ther-mal, central station solar photovoltaic, dispersed solar photovoltaic,

waves, and currents), combined with energy-storage systems, also

ap-pear to offer potential for renewable indigenous energy supplies and

reduced environmental impacts. These technologies cannot expected to

contribute to Maine's electricity supply until some time after 1986.

Maine should follow their development in other locations more

favor-able to their development.

D) Maine does not have the conditions and resources required for

ocean thermal and most forms of geothermal energy conversion. Hot dry rock geothermal energy conversion in Maine might be possible but would

not contribute to Maine's electricity supply until after the year 2000. Maine should follow its development in other, more favorable

geological locations.

E) Reliable quantification of the power and energy potential,

costs, and environmental impacts of the alternative technologies is

not possible without further basic data collection in Maine followed

by specific design studies. If Maine hopes to utilize these

technolo-gies in the future, such data collection and design studies will be

necessary.

F) Best case approximations of performance for the alternative

technologies indicate that, regardless of costs, they cannot

indivi-dually supply or eliminate the expected increase in demand for

elec-tricity. Based on available information, it is entirely conjectural

to estimate the possible composite performance if all the

alterna-tive technologies were implemented. Even the individual best case

ap-proximations are subject to possible errors which could lead to

se-rious undercapacity and economic problems if Maine were to rely on the

alternative technologies.

G) Many of the alternative technologies (solar space and hot

wa-ter heating, wind, central station solar thermal, central station

so-lar photovoltaic, dispersed soso-lar photovoltaic, waves, and currents)

are best operated in a fuel-saver mode, in which they supply energy as

it becomes available. Unless extensive energy storage is included,

these technologies provide on a random basis either peaking or

inter-mediate energy, rather than base load power.

On a statistical performance/demand basis these types of energy

facilities can present a "capacity credit" of "reliable" power within

a given utility system. This "reliable" power can be expressed as a

fraction of the rated capability per facility. There are current

in-vestigations which should result in a methodology for arriving at

"capacity credit" equivalencies for a number of dispersed energy

sta-tions. The studies are not complete.

H) Best case approximations of performance for the near-term

al-ternative technologies indicate that their electricity costs in 1986

will be between 50 and 100 mills/KWh. Actual costs will probably be

higher but can only be quantified by actual design studies. Estimated

costs for mid-term technologies fell in a range from 75 to 200

mills/Kwh in 1986 dollars. The above are "busbar" costs, that is, the

costs of electricity at the output terminals of the generation

plants. Allowance for funds used during construction (see p. 34) must

be added to these estimates to determine the total busbar costs.

I) The overall environmental effects of the alternative

techno-logies appear to be roughly equivalent to or possibly less than the

ef-fects due to coal-fired generation. The absence of commercial

experience or even full-scale prototypes makes quantification of the

impacts difficult.

J) Based on the information in Table 2.1, note that only

conver-sion of biomass, conservation, distributed solar space and hot water

heating, solid waste incineration, storage, and wind conversion are

only conservation, solid waste incineration, and storage have some

es-tablished commercial experience. The others of this group have the

po-tential to be commercially developed in time to supply energy for 1986.

It should be recognized that the necessary lead times for

design-ing and licensdesign-ing these alternative technologies may preclude their

availability by 1986 even though the commercial technology is

available by then.

1.0 INTRODUCTION

1.1 Scope of the Study

The Energy Laboratory of the Massachusetts Institute of

Techno-logy (MIT) was retained by the Central Maine Power Company (CMP) to

e-valuate several technologies (Table 1.1) as possible alternatives to

the construction of Sears Island #1 (a 600 MWe coal-fired generating

plant scheduled for startup in 1986). This report presents the

re-sults of the study.

Table 1.1

TECHNOLOGIES CONSIDERED

conversion of biomass

increased conservation

geothermal energy conversion

· ocean thermal energy conversion

fuel cells

solar energy conversion

conversion of solid wastes

storage of energy

wave energy conversion

ocean and riverine current energy conversion

· wind energy conversion

On a national scale, the technologies of Table 1.1 have

stimula-ted interest because of their independence from conventional fossil

and/or nuclear fuels and because they offer the potential of more

1.2 Methodology

The study of the technologies was based primarily on critical

re-views of the available literature, supplemented, when possible, by

discussions with researchers, government agencies, equipment vendors,

and architect/engineering firms. Each technology was reviewed

sepa-rately. The results of these separate studies are included as

ap-pendices. The body of this report presents comparative discussions,

based on the appendices, using four categories:

Status of Technological Development: description of the

alter-native approaches in terms of their principles of operation,

ma-jor components, operating experience, projected development

sched-ule, anticipated technical problems. This was a generic study of

the technologies per se.

Applicability to Maine: special requirements for utilization;

availability of requirements in Maine; potential energy

produc-tion in Maine; instituproduc-tional objecproduc-tions to use.

Economics of Operation: economic assumptions; capital and

ope-rating costs; projected electricity costs.

Environmental Consequences: air, water, and land use impacts of

conversion technology; impacts of ancillary operations;

envi-ronmental benefits.

1.3 Discussion

Increased efficiency in the generation and consumption of energy

and the use of renewable energy sources should, in general, be

en-couraged in the face of our nation's growing dependence on fossil

fuels. Several of the technologies studied by MIT offer this

poten-tial to Maine. An exploration in more detail would be necessary to

determine those most appropriate for contribution to Maine's energy

supply.

This study, however, had a narrower purpose in that it was

searching for alternatives which could possibly eliminate or delay the

need for the coal-fired 600 MWe generation planned at Sears Island.

For this search, the load forecast of CMP (Figure .1) was taken as a

given. Each technology was evaluated to answer the following:

1) Under what conditions could this technology supply

(con-serve) the power and energy to be supplied by Sears Island

#]?

2) What would be the best performance to be expected from this

technology?

In some cases, a successful commitment to a single or a combination of

alternative technologies could conceivably delay the need for coal

generation for a year or two although the energy costs would probably

be higher. This was not considered to be a true alternative, since

the plant would still be needed to supply Maine's lonq-term energy

Capability Responsibility, Millions of Kilowatts (106) Y) N i O cm CO c N.c - c Od .d . .~ -. .. . . - .

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1.4 Caveats

A. The reader should keep in mind several limitations associated

with comparative evaluations performed on the basis of the available

literature:

Comparison of alternatives is imprecise since critical

as-sumptions made by different authors are often unstated or

irreconcilable, particularly between very different

tech-nologies, e.g., solar energy conversion and burning solid

waste.

Published reports tend to be optimistic. Extrapolations to

Maine of reported pilot or demonstration plant experience

can only indicate gross costs or benefits. More detailed

design evaluations and specific engineering studies are

required before a firm commitment to any of the alternative

technologies can be made.

B. Uncertainty surrounds almost every facet of the analysis

per-formed in choosing alternative generation technologies to meet Maine's

electrical demand in 1986 and beyond. No absolute answers are

pos-sible in this situation. Usually, the wisest policy is to pursue

se-veral courses of action simultaneously. What should be avoided is the

closing off of options which may become very important in the

uncer-tain future.

C. To concentrate solely on one or more of the alternative

tech-nologies could conceivably leave Maine in a serious undercapacity

their hoped-for energy. The adverse consequences for Maine of such

undercapacity would be principally economic. However, both the

Fede-ral Power Commission (FPC, 1976, p. 5) and the National Electric

Reli-ability Council (NERC, 1976, p. 3) have warned of the possibility of

widespread capacity deficiencies by the mid-1980's. Such shortages

could lead to brownouts and blackouts. Utilities would probably

in-stall short procurement time generation in the form of gas turbines to

the extent possible. The present capacity of the manufacturers of gas

turbines is sized to meet normal growth requirements. The industry

would require several years to design, manufacture and install the

machinery required to increase gas turbine production. Gas turbine

installations would adversely affect the generation mix by poorly

matching generation characteristics to the load. The resulting mix

would contain too much intermediate and peaking capacity and too

little base load capacity. More light distillate oil would have to be

burned, if allowed by national energy policy.

Undercapacity has the effect of reducing reserve margins and the

associated carrying costs for capacity. Although there may be a

trade-off between the carrying costs for reserve margins and the costs

of reduced reliability levels, this issue is best addressed directly,

rather than "backed into" by a poor choice of technologies for

opera-tion.

D. Adverse environmental effects could also result from an

un-dercapacity situation. The urgency of bringing capacity on line might

create pressures for bypassing environmental hearings which require

time. Older, less efficient, and less environmentally sound plants

might have to be kept in service longer.

E. What happens if Maine concentrates only on the construction

of Sears Island #1? A commitment to the conventional coal alternative

does not altogether eliminate the possibility of an undercapacity

sit-uation, although it reduces its chances of occurrence. However, this

course of action could conceivably later have its own economic and

en-vironmental drawbacks. Several of the alternative technologies might

offer unique economic benefits which would be missed, such as

encour-aging new industries and increasing employment and, in the case of

conservation, reduced cost-of-living and doing business in Maine.

Re-liance on indigenous renewable energy sources would also help reduce

Maine's out-of-state energy payments. In some situations (e.g.,

ra-pidly rising coal costs), the alternative technologies might even

re-sult in lower consumer energy costs. Most of the renewable sources of

energy appear to be environmentally comparable to burning coal.

Choosing only the coal option could deny Maine the opportunity for

in-troducing new, possibly less environmentally harmful energy supplies.

F. Choosing to develop both the coal plant at Sears Island and

some set of alternative technologies also has associated problems.

The alternative technologies are more risky investments than a coal

plant, so someone will have to pay a risk premium to attract the

ne-cessary capital. If the alternatives are developed by the utility

in-dustry, either electricity consumers or electric utility stockholders

would pay the risk premium. If the alternatives fail or are not

eco-nomically competitive with conventional generation, someone must

ab-sorb the losses. Even so, it seems to be in Maine's best interests to

2.0 STATUS OF TECHNOLOGICAL DEVELOPMENT*

2.1 Principles of Operation

Our evaluation searched for technologies which could possibly be

substituted for Sears Island #1. Such technologies would have to be

capable of producing or conserving 600 MW of electrical power and

roughly 4 billion KWh of energy per year. In general either a few

large centralized facilities (e.g., biomass combustion power plants)

or numerous small decentralized facilities (e.g., wind turbines) offer

the best use of the characteristics of alternative technologies.

In the following discussions only the most promising form of each

technology will be considered. Thus, while it may be technically

pos-sible to erect a 1 KW wind turbine for every household, this

discus-sion would only consider the more likely design of several hundred 1-3

MW units. Furthermore, only the most promising of the candidate 1-3

MW wind turbine designs will be presented. Otherwise the list of

al-ternatives becomes unwieldy and the comparisons entirely

conjec-tural. The various appendices give more justification for the choice

of the following as the best prospective designs.

CONVERSION OF BIOMASS: Multiple harvesting in conjunction

with commercial logging and pulp operations would be used to remove

the presently noncommercial portions of the forest for use as fuel.

The fuel wood would be chipped in the forest and trucked to several

small, centrally located conversion plants. These plants would burn

*Note: The technologies were first examined for the intrinsic characteristics (capabilities, status of development and/or commer-cialization, environmental impact, and anticipated cost of generated electricity). In Section 4.0, the applicability of each technology to Maine is discussed.

the chips to produce steam for the generation of electricity. A plant

of about 50 MWe size appears to be optimal.

CONSERVATION: Utilities, industries, commercial

estab-lishments, and residential users would take action to reduce

elec-tricity consumption by foregoing demands and increasing the efficiency

of end use. Heroic changes in lifestyle are not considered.

Con-servation produces no electricity but might reduce the need for new

generation in 1986.

GEOTHERMAL ENERGY CONVERSION: In the absence of natural

wet or dry steam reservoirs, hot dry rock technology is needed to tap

any geothermal resources. Deep wells must be drilled, after which the

hot rocks would be fractured and water pumped through the cracks to

transfer heat to the surface. Depending on the temperatures involved,

the hot water would be used to vaporize water or another working fluid

to drive a turbine, generating electricity. Plant sizes on the order

of 100 MWe are considered.

OCEAN THERMAL ENERGY CONVERSION: Warm surface ocean water

would be used to vaporize a low boiling point working fluid to drive a

turbine, generating electricity. Cool ocean water, taken from depths

below 1500 ft, is used to condense the turbine exhaust. Floating

con-crete hulls with 100 MWe capacity are considered.

FUEL CELLS: Hydrocarbon fuels would be chemically combined

with air (oxygen), without combustion, to generate direct current

electricity. Power conditioning equipment would then produce 60 Hz

electricity for public use. Because modular design is basic to this

SOLAR ENERGY CONVERSION: Several solar technologies are

considered. At central station solar thermal plants area-extensive

mirror systems would focus sunlight on a central receiver-boiler to

develop steam. The steam would be used to generate electricity

imme-diately or the steam or generated electrical energy would be stored

for use when the sun was not available. Central plants on the order

of 100 MWe are considered. Central station photovoltaic plants would

utilize arrays of photovoltaic cells to instantaneously produce direct

current electricity. This would then be converted to 60 Hz

electri-city for public use. Central plants of 100 MWe are considered. Solar

space and water heating involves dispersed residence or

single-structure technologies. Either air or water would be circulated from

the solar collectors to the living area or hot water system. No

elec-tricity would be produced, but elecelec-tricity used for space conditioning

might be replaced by solar-derived energy, resulting in reduced demand

from conventional sources at those times when collectible sunshine was

available. Dispersed solar photovoltaic systems for small-scale

(single-structure) use would operate on the principles of the central

systems. Direct current from photovoltaic cells would be converted to

60 Hz electrical power to satisfy the demands of the user.

Storage technology is critical to most economic uses of solar

energy. The increased size of collection facilities to "charge" the

storage also places an economic burden on solar energy technologies.

CONVERSION OF SOLID WASTES: Municipal solid wastes would

be collected at a series of transfer stations and then transported by

truck to several central energy conversion plants. There, the solid

wastes would either be incinerated to produce steam for electricity

generation or processed into another form to be used as a

supplemen-tary fuel for coal- or oil-fired utility boilers. Incineration units

sized at about 50 MWe are considered.

STORAGE OF ENERGY: Storage devices would allow energy

col-lected or converted in one time period to be used in another, and

would result in more reliable and efficient operation of both

alterna-tive and conventional generation technologies. Dedicated storage

would be associated with a single conversion technology. Storage

could utilize thermal, pumped hydro, mechanical, or electrical

energy. System storage would store electricity from a variety of

sources. Storage facilities could be any size since their modular

units could be combined to form larger capacities.

WAVE ENERGY CONVERSION: Buoy-type systems or floating cams

could convert the kinetic energy of waves into mechanical energy to

compress air or pump water for eventual electricity production. Wave

energy systems would have to be moored off the coast with undersea

ca-bles for transmission of electricity to shore. The size of the

sys-tems would be limited by mooring and transmission considerations, and

would probably be on the order of 1-5 MW capacity.

OCEAN AND RIVERINE CURRENT ENERGY CONVERSION: River

cur-rents could be used to turn turbines for electricity production in a

manner similar to waterwheels. River current turbines would have to

be moored in the river and would require cable systems for energy

transmission to the shore. Unit sizes would be a function of river

WIND ENERGY CONVERSION: A tower-mounted, horizontal axis

turbine could convert the kinetic energy of the wind into rotational

energy to turn a generator to produce electricity. Proper siting and

storage would be critical to sustained, reliable electricity

produc-tion. Unit sizes from 1.5 MWe to 3 MWe are being considered.

2.2 Components of Alternatives

For most of the technologies there are critical new components

which are needed for successful commercial operation. In addition

there are other components which are essentially established,

off-the-shelf technologies. These are summarized in Table 2.1, along

with a list of the major anticipated technical problems and estimates

of the availability of the technologies.

2.3 Technical "Quantification"

For most of the technologies there is a shortage of adequate

ba-sic data about the available primary energy sources. The data which

are available have often been collected for purposes other than energy

assessments and, as a result, are incomplete or inappropriate. For

example, wind speed data have typically been collected near ground

level at airports (which are chosen for their low wind speeds). Such

data do not completely represent the elevated wind speed data which

would be found at an optimal wind turbine site. Collection efforts

for data on energy generation potential of wind, waves, currents, and

solar insolation in Maine would improve future assessments. Biomass

and solid waste production data are also needed on a more

site-specific basis. A particularly weak point in existing data is the lack of time-dependent information on a daily time scale.

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o a 4-- 4-) a·J O4-4J -IJ C C =n O 4 C c 3 3 O C - -In In C C L LE E U U E E S S *_ o 0r 00 CO cn 90 S.-0 In C 0 E S-o u S 0 IU L la 4 a) c Z (1 s- o O o_ r- E_{o 0} a -c.> 0a -r-_0r 4. In C n 0 4 0 O e . 4 4-) N O 4 'U c 5 4 0) -)

-

E

oC) aI E u, o >i 0 L 4 o N a) - y 4 -4C O m I r 0.. >

4-o

N' In C) In 40 O I 0 QO 0-E 4--₀ s-0 I0 'U s-0 0 L.) _ _

I_ _I

_

_

For several of the technologies, there is a trade-off between the

cost and design complexity and the energy production of the

techno-logy. The added cost and complexity result from the necessity of

col-lecting and storing energy for those periods when the basic energy

source (e.g., sunlight, wind, or waves) is not available. Matching

generation and storage is in general a complex and critical problem

and is best done as part of specific design studies. For this report

an attempt has been made to consider storage with central station

so-lar thermal and central station soso-lar photovoltaic generation, in

or-der to facilitate their comparison as base load technologies. Energy

Costs for these technologies would be more attractive if they were

operated in a fuel saver mode. In general, adding storage increases

energy costs while making capacity ratings more reliable.

Capacity and energy estimates were prepared (Table 2.2).

Capa-city estimates were made for the rated (maximum) operating capaCapa-city

for the likely unit design of each alternative technology. Energy

es-timates are based upon the rated capacity and typical capacity

fac-tors. Also given is the approximate number of units of each

techno-logy which would be needed to replace the contribution of Sears Island

#1.

The figures in Table 2.2 are annual averages since shorter time

scale data are generally unavailable. Annual averaging masks daily

and seasonal problems such as reduced insolation, wind speed

varia-tions, and so forth. To guarantee adequate year-long capacity and

energy production would require oversizing several alternative

CAPACITIES Technology Biomass Conservation b Ocean Thermal Geothermal Fuel Cells AND ANNUAL Unit Rated Capacity (MWe) 50 100 100 20 Table 2.2

ENERGIES FROM ALTERNATIVE TECHNOLOGIES

Energy Unitsa Unitsa

of Rated to Provide to Provide

Unit 600 MWe at 3.7 x 109 KWh (109 KWh) Rated

Capacity

__ _ .307 12 12 .614 .614 0.131 6 6 30 6 6 29 Solar

Central Station Thermal 100

Central Station Photovoltaic 100

Space & Water Heating

NAC Dispersed Photovoltaice .006 .614 .614 2.9x10- 5 3.1xlO-5 6 6 NAC See note d Solid Wastes Storageb Waves Currents Wind 50 1.5 1 1.5-3.0 .360 .005-.026f .001f .005-.010f

aIgnores daily and seasonal variation.

bDoes not produce any energy; replaces need

CProvides thermal not electrical energy; may be energy

dCapacity depends strongly on assumptions about

eBased on study for Arizona.

fStorage not included.

NA: not applicable. 25

for capacity

substituted for electrical

storage. 6 6 130,000 117,000 12 10 600-120 600 400-200 7 1 0-1 4 0f 3700f 740-370f -·__

Estimates of the impact of conservation on electricity demand are

highly unreliable; in addition, some conservation measures tend to

re-duce only peaking and intermediate capacity requirements, rather than

base load requirements. We estimate that an all-out conservation

ef-fort could theoretically eliminate 325 MW of capacity requirements and

2 billion KWh/yr of energy demand by 1986.

This is what could be saved only if the complete and sustained

conservation effort were implemented by the government on a national

basis. (Electricity customers in Maine cannot be asked to freeze

slowly in the near dark while the rest of the nation lives the "good

life.")

If a utility system has excess base-load energy, storage can be

employed at the system level to reduce or postpone new peaking and

in-termediate capacity requirements by making better use of existing base

load generation. System level storage in itself does not directly

serve system energy demands although it can provide additional

capa-city. Since system level storage depends on excess base load energy

to provide intermediate and peaking energy and capacity, it is not an

3.0 ENVIRONMENTAL EFFECTS

Appendix L (Environmental Impacts) presents the results of a

special literature review on the comparative environmental impacts of

the alternative technologies. Some authors have found the total

im-pacts of technologies such as burning solid wastes, burning forest

wastes, and geothermal energy conversion to be comparable to the

im-pacts of coal-burning plants.

The alternative technologies for electricity production are not

environmental panaceas. Several have as yet unresolved environmental

problems which could have a serious impact on Maine. Others, when in

operation, have minimal environmental impact.

Many of the alternative sources considered do rely upon

re-newable primary energy sources and avoid most of the environmental

air, water, and land pollution impacts of conventional coal, oil, and

gas generation. With adequate planning and good design, it appears

that most of these renewable primary energy resources can be utilized

indefinitely with no long-term environmental effects comparable to the

potential problems of coal mining and utilization. The construction

of the facilities requires materials and manufactured products for

which environmental impacts must be considered. There are substantial

economic costs associated with even some of the least environmentally

damaging technologies. Maine must decide if the benefits warrant the

additional costs.

The major impacts of the alternative technologies considered in

this report are given in Table 3.1. Conservation has the least

im-pact, closely followed by the dispersed solar energy-derived

technolo-gies, (thermal, photovoltaic) wind, current and wave conversion.

Cen-tral solar facilities and ocean thermal facilities may be in about the

middle. At the high impact end are the burning of solid waste, and

Table 3.1

SUMMARY OF ENVIRONMENTAL IMPACTS OF ALTERNATIVE TECHNOLOGIES

cr~~(

Energy Resource Depletion Conversion Area

Transmission Area Water Consumption Use of Air Space

Air Pollution - Particulate Air Pollution - Gaseous Water Pollution Construction Activity Heavy Metals/Toxic Thermal Discharge Solid Waste Visual Intrusion Noise Public Health Transportation TOTALS :E c. 1 3 3 1 3 1 1 1 3 1 1 1 3 1 1 1 -1 CD 1 3 3 1 1 1 1 1 4 1 1 1 4 1 1 2 27 01

(b

uD 1 4 3 1 1 1 1 1 4 1 1 1 4 1 1 2 28 C)

0

CD La 1 3 2 1 1 1 1 1 3 1 1 1 2 1 1 1 22

0

U) _., CD U) (D 2 3 3 4 1 4 3 3 3 3 4 2 3 3 2 ) SOLAR c)

0

0

o

1 3 1 1 1 1 1 1 2 1 1 1 2 1 1 1 20 I -_. 1 3 1 1 1 1 1 1 2 1 1 1 2 1 1 1 20 ,) :0

0

c-0

1 4 3 1 3 1 1 1 3 1 2 1 3 1 1 1 28

Impact Rating: 1 - negligible 2 - slight

3 - moderate 4 - severe

O

indicates ratings for which the more optimistic value of a spread was chosen.

29 G) O

0

CD 01 __J.. 3 3 3 3 4 2 3 2 3 2 1 C4

0

U) U) 2 4 3 3 1 4 3 3 3 2 4 2 3 3 1

C

C fD U) 4 2 2 2 1 1 1 1 3 1 2 1 2 1 1 1 26 n C--c') =r 1) -S 01 3 ml 1 4 3 2 3 1 1 1 3 1 3 1 3 1 1 1 30

0

CD o 1 --I 3 01 2 4 3

)3

)l 2 3 1 2 1 1 ) 2 2 30 C-)

0

ID 1

rt

-.

0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 16

4.0 APPLICABILITY TO MAINE

Each of the technologies was examined to identify special

re-quirements for its satisfactory production of electricity in Maine

(for example, wind speed regimes, solar insolation levels, etc.).

When possible, the ability of Maine to provide these requirements was

quantified and estimates were made of the resulting available

electri-cal capacity and energy. This approach is necessarily subject to the

possibility of large errors because the performance of the

technolo-gies is highly site-dependent. Specific siting and design studies

were beyond the scope of this evaluation.

In an attempt to draw reliable conclusions about the

alterna-tives to construction of the Sears Island 600 MWe plant, a best case

approach was used to evaluate the uncertain performance information of

the alternative technologies. The maximum electrical output of each

technology under best case assumptions was determined. This number

could then be compared with the minimum requirements for replacing the

Sears Island plant. In some cases (e.g., ocean thermal energy)

Maine's total resources were clearly too limited to allow operation of

the alternative technology.

In other cases (e.g., wind energy) it is conjectural to say what

Maine's resources are, but statements can be made like, "Over 2000

one-MWe wind turbines would be needed to produce 95% reliable 600 MWe

capacity." The reader is cautioned to note that whether 2000 one-MWe

wind turbines can actually be sited, licensed, and built by 1986 is

only partly a technical question. Considerable institutional and

of wind turbines would be possible. The numbers given in the

fol-lowing two sections represent our estimates of the best possible

per-formance, without regard to the non-technical barriers which might

exist or arise.

4.1 Special Requirements

The special requirements discussed in this section are not

tech-nological requirements, such as the development of manufacturing

meth-ods for the mass production of wind turbine blades. Rather, the

fol-lowing special requirements encompass the basic energy and raw

ma-terial needs of the alternative technologies (Table 4.1).

With two exceptions, all of the technologies could clearly

con-tribute to the electrical energy supply in Maine.

A. Ocean thermal systems will not operate in the relatively cold

and shallow waters off the Maine coast.

B. Geothermal systems must rely upon hot dry rock technology

be-cause Maine has no known hydrothermal or geopressured resources.

No data are available on the extent and characteristics of

Maine's hot dry rock resources.

4.2 Estimates of Energy and Capacity

The fact that the remaining technologies can theoretically be

operated in Maine is interesting but may be only academic. More

im-portant is the question of how much energy and capacity can be

pro-duced or saved by the technologies.

Table 4.1

SPECIAL REQUIREMENTS FOR ALTERNATIVE TECHNOLOGIES

Technology Requirements Availability in Maine

Biomass Biomass supply 90% forested; collection

could be a problem;

compe-tition from pulp industry. Conservation Mandatorv Measures

--Ocean Thermal Geothermal Fuel Cells Solar Energy Solid Wastes Storage Waves Currents Wind

and Public Support

Thermal gradient

totaling 150C

Hot dry rocks

Clean gaseous or liquid fuels from coal Solar insolation Solid waste supply Suitable sites Coastal Access River Sites High Wind Speeds None Unknown None

Low insolation levels; a(

verse weather

Small, rural population;

collection problems

Limited

300-400 miles of open wal

coastline; fishing inter*

ference

Numerous; icing and ship

interference

Coastal reoions and moun

I-ter

5.0 ECONOMICS

Because there is, in general, little or no commercial experience

with the alternative technologies studied here, estimates of their

cost are necessarily approximate. In many cases there are no data

whatsoever on the costs of certain components or operations.

The cost data which exist are very sensitive to the assumptions

made in their derivation. Unfortunately many of those assumptions are

not reported in the literature, making it necessary for us to

inter-pret the available data in order to draw even rough comparisons. The

technical appendices have noted these assumptions and include

inter-pretations when appropriate.

5.1 Economic Assumptions

In order to allow at least an order of magnitude comparison of

the economics of the various alternative technologies, a common

eco-nomic methodology was applied. The numbers which this methodology has

produced are probably low in an absolute sense but should be

repre-sentative of the relative costs of the alternatives. Only a specific

design study including issues such as siting, licensing, transmission,

and environmental impact minimization could provide accurate absolute

cost data. Even then, costs will be no more reliable than the

avail-able performance data, most of which are still based on prototype

units that are still in the experimental stages or "paper" designs.

Our basis of cost comparison of the electricity produced by the

various technologies has been the cost in mills/KWh, at the output

terminals of the generation plant, . A comparison year, 1986, was

chosen. All reported costs have been converted to 1986 dollars by

using an escalation rate of 5% per year. Escalation was not

compoun-ded.

No attempt was made to determine a lifetime cost for operating

the various technologies. Costs after 1986 were not compared as it is

considered to be too far into the future for numbers to make sense.

The quality of the economic and operating data simply does not justify

adding another set of assumptions to develop lifetime costs. If a

specific design study were undertaken, then such a year-by-year

an-alysis should be performed.

Electricity costs were found by dividing the total annual

ca-pital and operating costs by the energy produced in one year.

Matura-tion problems, which might cause low energy producMatura-tion during the

first few years of plant operation, were ignored. Whenever

as-sumptions were necessary, optimistic but reasonable asas-sumptions were

used, so the resulting energy costs are probably as low as possible.

In most cases, it was impossible to quantify the effects of mass

pro-duction of equipment and services on the 1986 prices, so this effect

is not included. No attempt was made to determine secondary economic

effects (increased employment, sales of goods and services in Maine,

etc.) of the alternative technologies as a possible credit against

their costs.

Annual capital costs were determined by converting the capital

investment for an alternative technology, say a wood burning plant,

into an annual levelized charge. A levelized fixed charge rate (LFCR)

of 18% was used for all the alternatives and reflects the annual cost

of owning a capital investment. Debt service, equity return,

depreci-ation, state and local income taxes, investment tax credit, insurance,

Service life strongly affects the calculation of LFCR, with

im-portant implications for the evaluation of the alternative

technolo-gies. Because they are new technologies, their service life can only

be estimated and will certainly vary from one technology to another.

Given this uncertainty and the uncertainties of the basic economic

da-ta, there seemed to be little justification for adding the refinement

of individually calculated LFCR's. Over a range of posssible service

lives (10-30 years), and using the assumptions of Table 5.1, the value

of the LFCR changed between roughly 15% and 19%.

Table 5.1

LEVELIZED FIXED CHARGE RATE ASSUMPTIONS

Bond Interest 9.75%

Bond Fraction 52.00%

Common Stock Interest 14.50%

Common Stock Fraction 34.00%

Preferred Stock Interest 10.00%

Preferred Stock Fraction 14.00%

State Income Tax 7.00%

Federal Income Tax 48.00%

Investment Tax Credit 10.00%

Investment Tax Credit Fraction 75.00%

Property Tax, Insurance 1.50%

Service Life - N 10-33 years

Allowance for funds used during construction (AFUDC) was not

in-cluded in the costs calculated for the technologies. Depending on the

length of the construction period these could increase the capital

charges by as much as 30%. If this increase were included instead in

the LFCR, LFCR would range between 19% and 24%. An LFCR of 18% was

arbitrarily chosen as an optimistic but representative LFCR.

Operating costs were taken directly from the literature,

calcu-lated from known components of plant operation, or estimated as a

fraction of plant investment.

Energy generated was based on the rated capacity of the

alter-native technologies and their estimated capacity factors. In most

cases there is no commercial experience on which to base forced outage

and maintenance estimates.

5.2 Cost of Electricity

Based on the optimistic approach outlined in Section 5.1, 1986

costs of electricity from each of the alternative technologies were

derived (Table 5.2). These costs should be considered as best case

numbers, (i.e., "most optimistic"), in the sense that it is expected

that commercially installed units will not provide electricity below

these costs, even with reasonably likely technological and

manufactu-ring breakthroughs. Actual commercial costs may turn out to be higher

by a factor of two or more.

Conservation is one method that can actually pay consumers for

their investment. The economics of conservation vary according to the

measures taken and the cost of the electricity.

Storage costs have two components: the cost of the stored

energy, which depends on its generating source, and the cost of the

storage equipment. The incremental storage equipment costs are the

same for all generating units, so the determining factor is the cost

of the stored energy. Base load generation is needed so that the

energy taken from storage can be economically competitive with

Table 5.2

OPTIMISTIC ELECTRICITY COSTS FROM ALTERNATIVE TECHNOLOGIES

Technology Range of Busbar Electricity Costs Mills/KWha in 1986 dollars

Conversion of Biomass 50 - 70

Conservationb

Ocean Thermal Energy Conversion 70 - 90

Geothermal Energy Conversion 25 - 80

Fuel Cells 55 - 70

Solar Energy Conversion

Central Station Thermal 600 - 800

Central Station Photovoltaic 346 - 3000C Space Heating and Coolingd

Dispersed Photovoltaice

Conversion of Solid Wastes 40 - 90

Storage of Energyb

Wave Energy Conversionf 25 - 116

Ocean and Riverine Current Energy Conversion 200 - 260

Wind Energy Conversion 65 - 100

aThese figures do not include AFUDC. Depending upon fuel costs, if AFUDC is included, the busbar cost of electricity can increase up to 30%

bCosts depend on the cost of the energy conserved or stored.

CCost depends on assumptions made about projected reductions in photovol-taic cell costs.

dMay be economic for average homeowner (depending upon his alternatives). eMay be economic if photovoltaic cell costs fall drastically, but utility

backup supply still needed.

flow by as much as a factor of 3 due to missing costs.