# Consumer Preferences for Wood-Pellet-Based Green Pricing Programs in the Eastern United States
## 3 Methods
### Attributes and Corresponding Levels  
The attributes and their corresponding levels were developed based on the need to account for key features of GPPs for co-firing conversion facilities. Length of contract (LC), variability of payments (VP), flexibility of contracts (FC), reduction of CO2 emissions (RC), location of energy generation (LG), and the green pricing premium payment (GP) were the six selected attributes identified from previous studies as having a large impact on consumer choice [19; 24; 25; 28; 43; 44; 45; 46; 47; 48] (Table 1). The LC attribute addresses regularity, which is the periodicity of payment cycles for energy service provision. The contract length for the energy provision refers to the duration for the service involving the supply of a given amount of electricity and an REC, after which the customer can opt out of the contract. [PERSON] et al. [46] used a similar attribute termed a 'cancellation period' where they used monthly, quarterly, semi-yearly, and yearly as their attribute levels. For their study, the attribute level yearly was considered as the omitted variable. For the simplicity of survey design, we designated LC levels as 6 months (6 M), 12 months (12 M), and 24 months (24 M). Owing to consumer aversion to longer contracts for most consumer goods, we designated 24 M as the omitted variable [25; 45]. Price guarantee identifies how much consumers value price stability, which is measurable in terms of how long the price will remain stable [46]. For our study, this concept was captured as the VP attribute to account for how market forces beyond the control of the conversion facility, such as the cost of wood pellets, influence the price of green energy certificates. For this attribute, we applied the following levels: fixed premium (FP) \begin{table}
\begin{tabular}{c c c} \hline \hline
**Green Energy Attributes** & **Description** & **Levels** \\ \hline \multirow{3}{*}{**Length of contract (LC)**} & The contract length for the energy provision & 6 months (6 M) \\  & service that involves supply of electricity and a & 12 months (12 M) \\  & renewable energy certificate (REC). & 24 months (24 M) * \\ \hline \multirow{3}{*}{**Variability of payments (VP)**} & Variability of payments due to market factors & Fixed premium (FP) \\  & can be accounted for by RECs that have a fixed & Fluctuating premium \(\pm\) 5\% (F5) \\  & premium or fluctuating premium. & Fluctuating premium \(\pm\) 10\% (F10) * \\ \hline \multirow{3}{*}{**Flexibility of contract (FC)**} & The electricity consumer has the option to opt & Opt out of contract with a penalty (PEN) * \\  & out of the contract with or without a penalty. & Opt out of contract without a penalty (NOPEN) \\ \hline \multirow{3}{*}{**Location of energy**} & The location of the energy provision service & In State (IN-STATE) \\  & can be In State or out of state. & Out of state (OUT-STATE) * \\ \hline \multirow{3}{*}{**Reduction in CO2 Emissions (RC)**} & Co-firing conversion plants that incorporate & 1–5\% (LOW) * \\  & wood pellets can result in local reduction of & 6–10\% (MED) \\  & CO2 emissions. & 11–20\% (HIGH) \\ \hline \multirow{3}{*}{**Green Pricing Premium**} & The payment vehicle in the form of a biomass & USD 10/MWh \\  & renewable energy certificate (REC) added to & USD 20/MWh \\  & the monthly electricity bill. With a charge for & USD 30/MWh \\ \cline{1-1}  & every Megawatt hour of electricity supplied to & USD 40/MWh * \\ \hline \hline \end{tabular} Note. * Indicates that the attribute levels (M24, F10, PEN, OUT-STATE, LOW and USD 40/MWH) were the omitted/baseline variables.  
\end{table} 
Table 1: Summary of attributes and levels used to create choice experiment questions. and premiums fluctuating by (\(\pm\)5% (F5)) and (\(\pm\)10% (F10)) within the chosen contract length. The F10 was considered as the baseline variable due to customer aversion to higher percentage fluctuations in premium [25; 26]. An important feature of most GPPs is that consumers have an opt out alternative [45].