Power Supply & Demand

Tony RamunnoDirector, Engineering & Project Management

Great River Energy

Great River Energy

• G&T Cooperative• 28 Member Cooperatives

– Customer Interface• 634,000 Members (Owners)• Sales:

– 57.4% Residential – 40.2% Commercial and Industrial,

Agriculture– 2.4% Seasonal

• 5th largest G&T in nation• Second largest utility in Minnesota

Tony Ramunno - Director Engineering & Project Management - Transmission

Service area covers 60% of Minnesota

Great River EnergyGreat River Energy

Nearly 850 employees (in MN and ND)

2,800 MW of generation4,500 miles of transmission linesTotal assets: $2.3 billion

Overview of Presentation

• Generation types/cost/application• Power Delivery – Transmission• Correlation of load to electrical infrastructure• What can we do!

Introduction

• Electricity Is not Magic – Can’t be stored/warehoused– Ordered, Manufactured, and delivered “on-demand”– Electricity usage and production costs are directly

related!• Infrastructure must be built to accommodate

“peak demand”– Assets are expensive ($$ and lead time)– Users of electricity share the cost

Power GenerationPlant Type Cost to Build Cost per MW Response Flexibility

Peaking (Gas, Oil) $ $$$$ Excellent

Intermediate (Gas) $$$ $$$ Good

Baseload (Nuke, Hydro, Coal)

$$$$ $ Poor

Wind $$ $$$ None (availability of wind)

The Lowest Cost Plant is the one not built!

Matching Generation & Load Types

Baseload GenerationRun Continuous

IntermediateRun as Planned/Needed

Peaking Run When Necessary

Low Cost Generation

High Cost Generation

Continuous Load

Cycling, Seasonal, other predictable Load

Unpredictable or added to high Load timeframe

Power Delivery System OverviewTransmission Must Cover “peak load”

PurchasedPower

GeneratingPlants

BulkTransmission

BulkTransmissionSubstation

Load ServingTransmission

DistributionSubstations

Distribution Lines

Power is generated or purchased

Bulk transmission (DC line and >115kv) moves the power to transmission substations, allows reserve sharing, and integrates resources into a regional grid

distribution substations drop the voltage down

Load serving transmission (<115kv) moves the power to distribution substations

These substations drop the voltage down

distribution lines move the power to the end customer.

Typical Utility Demand Curve

Ideal Load Curve!

What Can We Do!1. Understand/manage process energy usage

• Energize/de-energize frequency/duration• Staging starts/stops to levelize load

2. Consider energy in utilization equation• Is there operational flexibility?• Can facility load be shifted to off-peak times?

3. Consider energy in equipment selection• Energy efficiency – upfront vs. lifetime costs

Working Together

• Collaborate with Electric Utility– Time of day or time of year load benefits– On-site emergency generation capabilities– Load shedding or other flexibility during times of

emergency• We all share the costs for Electrical Infrastructure! • We all share the savings of deferred/delayed

infrastructure!

Questions