# Presentation: 769701

## Representation of Renewable Energy in ModelsNREL Analysis Seminar Series

- Walter Short
- February 8, 2001

## What Kinds of Models Are We Talking About?

- A wide variety of models for renewables:
- Design analysis
- Systems engineering
**Market penetration models**
- project energy prices and quantities out in time
- fuels and energy technologies compete for markets
- may or may not include:
- balancing of supply and demand through price
- macroeconomic feedback

## Modelers’ Dilemmas 

- No model is ever finished (if it is, it’s not being used)
- No model can answer all questions (but it’s too expensive to build a model for each question)
- Insightful model results are easy to dismiss
- Transparent models can’t do much
- Economics are difficult; social factors are incredible.
- Zero is the wrong input

## EIA’s National Energy Modeling System

## Electric Renewables in the AEO2001 Reference Case

## Energy Prices in the AEO2001 Reference Case

## Non-hydro Electric Renewables in EIA Analyses

- 2

- 3

- 6

- 14

- 1.4

## Unique Aspects of Modeling RE

- Capital cost dominates
- Dispersed, non-transportable resource
- Intermittency of wind and solar resource
- Alternative uses for biomass resources
- Benefits
- environmentally benign
- modular
- domestic resource
- inexhaustible resource

## Major Issues in Modeling Wind Energy

- Transmission: access to existing lines, new lines
- Intermittency: system reliability, capacity planning, bidding/dispatch
- Resource: quality, amount, access (terrain, roads, environmental and social factors)

## Slide 10

## Selected NEMS Constraints on Wind Energy

- Up to 200% capital cost penalty for site access - varies by region
- 1% capital cost penalty for every 1% in annual national growth above 25%/year
- No builds in one region to serve another region
- Intermittency:  max 10% of regional generation; capacity credit = 75% of cap factor

**nrel:**
- These are the principal constraints on wind.  There are others.
- We examined the impact of these by running NEMS AEO99 version  at OnLocation

## Wind Energy Constraints in NEMS

**GW**

**nrel:**
- Done by OnLocation with NREL
- sequential removal of constraints
- removal of all constraints yields tremendous growth by 2020 relative to the reference case
- It appears that it’s largely due to interregional builds, but that’s not the case

## nrel:

**nrel:**
- If you don’t use the lower quality class 4 wind, you can produce only 40.9 GW nationwide under the constraints assumed

## Major Advances Needed in Modeling Wind Energy Markets

- Transmission
- Access to and expansion of existing lines
- Inter-regional DC lines
- Transmission pricing
- Intermittency
- Low availability
- Short-term variability - cost of ancillary services
- No control - multiple wind sites
- No knowledge of when - bidding, short-term forecasting
- Resource estimation and access costs

## Biomass Modeling

- Biomass resource data
- Central electric biomass power
- Cofiring
- Industrial biomass use
- Ethanol production
- Alternative fuel vehicle modeling

## 2020 Biomass Supply Curves

## Cofiring in NEMS

- Cofiring limited to maximum of 5% of input fuel by heat content
- no capital cost
- Cofiring limited by regional resource availability
- 50 mile radius
- was 2% national average; expected to increase

## Cofiring Limits

- “Both” refers to the option to cofire at 5% with no capital
- cost or at 15% with a capital cost of $225/kW

## NEMS Industrial Biomass Energy

- Focussed on pulp and paper industry
- Paper/pulp demand determines biomass available, i.e. not tied to biomass supply curves
- All used for cogeneration (no economics)
- No tracking of capacity
- no retirements of old Tomlinson boilers
- no change in heat rates over time

## Ethanol in        NEMS

- AEO2000
- Reference
- Case

## AEO2000 Cellulosic Ethanol Production

- 20%

- 15%

- 10%

- 5%

- 5%

## Alternative-Fuel Vehicles in NEMS

- Two ethanol vehicle types - flex and neat
- Compete first with 13 AFV types
- Then a composite AFV competes with gasoline and diesel
- in 6 auto and 6 truck markets in each region (no flex-fuel SUVs)
- based on vehicle cost, fuel cost and availability and 7 other factors.
- Stock turnover is accounted for.

## Non-Blended Ethanol Demand

- * AFV share/Flex share/Neat share of new sales in 2020

- 52 / 35 / 15

- 22 /  /

- 27 / 1.4 / 0.2

## Major Issues in Modeling Bioenergy Markets

- Competition for Resources: land, residues
- Cofiring: resource access; costs
- Cogeneration: Pulp/paper
- Ethanol: infrastructure development, oxygenate market; AFV

## Photovoltaic Modeling Issues

- PV in buildings
- correlation of PV with load
- net metering
- Green power
- Future cost/performance

## NEMS Photovoltaics in Buildings

- Separate residential and commercial models
- Residential model focus on new homes
- no off grid
- only 30% of new homes
- full net metering
- competes with delivered electricity price; not other distributed sources
- includes “Million Solar Roofs” program
- Retrofits set as small fraction of new homes

## PV in AEO2001

## Geothermal Power Modeling Issues

- Resource estimation
- hydrothermal
- enhanced geothermal systems
- Siting/environmental issues
- Transmission access

## Geothermal in NEMS

- Explicitly include hydrothermal power and geothermal heat pumps
- Hydrothermal power
- Supply curve of 51 potential sites each with 4 quantity/cost points
- System costs no longer scale with size
- All intra-site deployment delays removed

## AEO2001 Geothermal Supply Curve

## Electric Renewables in the AEO2001 Reference Case

## Summary	

- There are unique aspects to modeling RE
- resources: wind, biomass, geothermal
- transmission: existing, new
- intermittency
- benefits
- NEMS addresses many of the issues, but not all
- Many opportunities exist to improve the representation of renewables in models