DOI: 10.5061/dryad.95x69p8r6
title: Flexibilization or biomethane upgrading? Investment preference of German biogas plant operators for the follow-up of guaranteed feed-in tariffs

description: This dataset reports the results of a discrete choice experiment with 183
 German biogas plant operators designed to elicit the respondents’ plans
 for biogas utilization pathways after the end of guaranteed feed-in
 tariffs. Participants could choose between ‘flexibilization’ for
 demand-based electricity generation and conversion to biomethane upgrading
 for direct feed-in into the natural gas grid. A binomial logit model
 revealed a 37% probability of switching to biomethane upgrading. These
 plants are characterized by higher capacities, several involved
 shareholders, secured succession, costly digestate disposal and belonging
 to the upper performance quartile. Mixed logit estimations conducted
 separately for the two investment concepts revealed a very high overall
 willingness to invest: 71% for flexibilization and 82% for biomethane
 upgrading. The respondents demand a return on investment of 19% for
 flexibilization and 26% for biomethane upgrading. Within the
 flexibilization, twofold overbuilding (installed capacity equals 2 times
 the rated power) is clearly preferred to fivefold overbuilding. For the
 biomethane upgrading, private ownership of the upgrading plant is
 preferred to a joint investment in a central upgrading facility. Limiting
 the use of energy crops reduces the propensity to invest in both models,
 while a longer utilization period enhances it. The respondents consider
 lack of planning reliability as the biggest obstacle to invest, followed
 by long approval procedures and high investment costs due to restrictive
 legal requirements.
description: # Flexibilization or biomethane upgrading? Investment preference of German
 biogas plant operators for the follow-up of guaranteed feed-in tariffs
 A discrete choice
 experiment with 183 German biogas plant operators designed to elicit the
 respondents’ plans for biogas utilization pathways after the end of
 guaranteed feed-in tariffs. Participants could choose between
 ‘flexibilization’ for demand-based electricity generation and conversion
 to biomethane upgrading for direct feed-in into the natural gas grid. ##
 Description of the data and file structure In the survey, participants
 were asked to provide basic characteristics of their biogas plant, such as
 capacity specifications, substrate input and the number of other biogas
 plants in the vicinity. The participants were then asked to decide which
 of the two concepts, flexibilization or biomethane upgrading, they would
 consider for their plant in the first stage. This choice is recorded as a
 dummy variable. Since extended operation in the status quo is not possible
 and an investment has to be made, but no specific investment concepts were
 presented in this stage, no opt-out variant was considered. Based on this,
 three investment alternatives of the previously selected concept were
 presented. In addition, a status quo alternative was offered at this
 second stage, which effectively implied the decommissioning of the biogas
 plant. The questionnaire was divided into 2 blocks of 6 decision
 situations each. This results in a panel data set that contains a total of
 18 observations (rows) per participant from the 6 choice situations per
 participant and 3 alternatives to be chosen in each case. The raw data
 regarding the time of data collection was removed to reduce the number of
 direct identifiers: datetime; numtime; date; year; month; time_month; day.
 The data will be made available on request. Description of variables: |
 **Variable** | **Unit** | **Explanation** | | ------------------------ |
 ----------------- |
 ---------------------------------------------------------------------------------------------- | | installed capacity | kW<sub>el</sub> | installed capacity of the biogas plant | | rated power | kW<sub>el</sub> | rated power of the biogas plant | | commisioning year | Year | year of the commissioning of the plant | | cooperativ plant | Number | plant is managed with several operators | | energy crops | % | share of energy crops in substrate input | | animal manure | % | share of animal manure in substrate input | | residues | % | percentage share of residues in substrate mix | | heat sale | % | share of heat sold externally | | heat price | ct/kWh | price for heat sold externally | | neighbours | Number | number of biogas plants within 3km radius of the own plant | | animal intensive region | Dummy | farm is located in a region with intensive livestock production in north-west Germany | | top 25% | Dummy | personal ranking in the successful 25% of farms with biogas plants | | lower 25% | Dummy | personal ranking in the less successful 25% of farms with biogas plants | | arable land | hectar | arable land under cultivation | | grassland | hectar | grassland under cultivation | | special crops | Dummy | farm cultivates special crops | | pigs | Number | number of pigs kept | | cattle | Number | number of cattle kept | | poultry | Number | number of poultry kept | | red area | Dummy | farm is wholly or partly located in the nitrate-sensitive area (‘red area’) | | storage | Dummy | farm has sufficient storage capacity for animal manure and digestate | | digestate disposal | Dummy | farm has to dispose of digestate at a charge due to the fertiliser ordinance | | after ukraine conflict | Dummy | completion of survey after the outbreak of the Ukraine conflict (24 Feb 2022) | | age | Number | age of participant in years | | successor | Dummy | farm succession is secured | | farming education | Dummy | participant has an agricultural education (training, technical college) | | higher farming education | Dummy | participant has a higher agricultural education (higher agricultural school, master craftsman) | | university | Dummy | participant has a university degree in agriculture | | overhaul | Likert scale 1-5 | estimation of the repair costs for subsequent use of the plant | | safety feasibility | Likert scale 1-5 | assessment of the feasibility of implementing safety requirements | | planning security | Likert scale 1-5 | statement: Insufficient planning certainty prevents investment | | plans investment | Likert scale 1-5 | operator has informed himself about connection concepts and is planning an investment | | needs subsidy | Likert scale 1-5 | economic operation of the plant is only possible with government subsidies | | choice\_number | Number | Number of the choice situation presented to a participant (1 to 6) | | Case | Number | ID of all choice situations | | Alternative | Number | Number of the Alternative of a choice situation (1 to 4) | | Choice | Dummy | Dummy equals 1 if participant chose the alternative; else zero | | questionaire | Number | Identifier for block of choice sets presented to a participant (1 or 2) | | concept\_choice | Dummy | equals 1 if participant chose flexibilization, 2 if biomethane | | profit | €/kW<sub>el</sub> | Profit Attribute of a Choice Alternative | | capital\_requirement | €/kW<sub>el</sub> | Investment Attribute of a Choice Alternative | | passiveFlex | Dummy | Equals 1 if an alternative contains the attribute, else 0 | | doubleFlex | Dummy | Equals 1 if an alternative contains the attribute, else 0 | | fiveFlex | Dummy | Equals 1 if an alternative contains the attribute, else 0 | | on\_site\_upgrading | Dummy | Equals 1 if an alternative contains the attribute, else 0 | | collective\_upgrading | Dummy | Equals 1 if an alternative contains the attribute, else 0 | | share\_energy\_crops | % | Maximum possible proportion of energy crops in an alternative | | duration | year | Period of use of the Alternative | ## Sharing/Access information Data was derived from a survey conducted between January and October 2021 via the *Unipark* platform. Due to few participants and energy market distortions in the aftermath of the conflict in Ukraine a second round was conducted between March and October 2022. The survey was initially distributed by industry interest groups, chambers of agriculture and advisory rings. In addition, the survey was advertised in authors’ presentations, and stakeholders were also contacted directly by email or phone. To encourage participation, a two-part video podcast was recorded in cooperation with a biogas consulting company. In the first part, both investment concepts flexibilization and biomethane upgrading were explained, followed by a request to participate in the survey. As an incentive to complete the survey, the second part of the video podcast was offered at the end of the survey, in which profitability analyses were presented for selected concepts. ## Code/Software The choice experiments D-efficient design was generated with the module Dcreate in Stata 17 (Hole, 2016). In order to test whether there is a difference between the participants who choose flexibilization and those who choose biomethane upgrading at the first stage of the survey, a binomial logit model was estimated. The choice data of the two subsamples were analysed separately using a mixed logit model, drawing on the *mixlogit* module in *Stata 17* (Hole, 2007).