# Forecasting Brazilian Ethanol Spot Prices Using LSTM

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## Abstract

**:**

## 1. Introduction

## 2. Related Work

## 3. Methodology

#### 3.1. Data

#### Data Pre-Processing

#### 3.2. LSTM Networks

#### 3.3. Proposed Model and Benchmarks

## 4. Results and Discussions

#### 4.1. Learning Curves

#### 4.2. Forecasting Results

#### 4.3. Visualising the Predictions

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Goldemberg, J. The ethanol program in Brazil. Environ. Res. Lett.
**2006**, 1, 014008. [Google Scholar] [CrossRef] - Silva, G.P.D.; Araújo, E.F.D.; Silva, D.O.; Guimarães, W.V. Ethanolic fermentation of sucrose, sugarcane juice and molasses by Escherichia coli strain KO11 and Klebsiella oxytoca strain P2. Braz. J. Microbiol.
**2005**, 36, 395–404. [Google Scholar] [CrossRef] - Lopes, M.L.; de Lima Paulillo, S.C.; Godoy, A.; Cherubin, R.A.; Lorenzi, M.S.; Giometti, F.H.C.; Bernardino, C.D.; de Amorim Neto, H.B.; de Amorim, H.V. Ethanol production in Brazil: A bridge between science and industry. Braz. J. Microbiol.
**2016**, 47, 64–76. [Google Scholar] [CrossRef] [PubMed][Green Version] - Ministry of Agriculture, Fisheries and Supply—Ethanol Archives. Available online: https://www.gov.br/agricultura/pt-br/assuntos/sustentabilidade/agroenergia/arquivos-etanol-comercio-exterior-brasileiro/ (accessed on 11 November 2021).
- Carpio, L.G.T. The effects of oil price volatility on ethanol, gasoline, and sugar price forecasts. Energy
**2019**, 181, 1012–1022. [Google Scholar] [CrossRef] - EIA—Today in Energy. Available online: https://www.eia.gov/todayinenergy/detail.php?id=47956 (accessed on 11 October 2021).
- Hira, A.; de Oliveira, L.G. No substitute for oil? How Brazil developed its ethanol industry. Energy Policy
**2009**, 37, 2450–2456. [Google Scholar] [CrossRef] - David, S.A.; Inácio, C.; Tenreiro Machado, J.A. Quantifying the predictability and efficiency of the cointegrated ethanol and agricultural commodities price series. Appl. Sci.
**2019**, 9, 5303. [Google Scholar] [CrossRef][Green Version] - David, S.; Quintino, D.; Inacio, C.; Machado, J. Fractional dynamic behavior in ethanol prices series. J. Comput. Appl. Math.
**2018**, 339, 85–93. [Google Scholar] [CrossRef] - Tapia Carpio, L.G.; Simone de Souza, F. Competition between second-generation ethanol and bioelectricity using the residual biomass of sugarcane: Effects of uncertainty on the production mix. Molecules
**2019**, 24, 369. [Google Scholar] [CrossRef] [PubMed][Green Version] - Herrera, G.P.; Constantino, M.; Tabak, B.M.; Pistori, H.; Su, J.J.; Naranpanawa, A. Long-term forecast of energy commodities price using machine learning. Energy
**2019**, 179, 214–221. [Google Scholar] [CrossRef] - de Araujo, F.H.A.; Bejan, L.; Rosso, O.A.; Stosic, T. Permutation entropy and statistical complexity analysis of Brazilian agricultural commodities. Entropy
**2019**, 21, 1220. [Google Scholar] [CrossRef][Green Version] - Barboza, F.; Kimura, H.; Altman, E. Machine learning models and bankruptcy prediction. Expert Syst. Appl.
**2017**, 83, 405–417. [Google Scholar] [CrossRef] - Alameer, Z.; Fathalla, A.; Li, K.; Ye, H.; Jianhua, Z. Multistep-ahead forecasting of coal prices using a hybrid deep learning model. Resour. Policy
**2020**, 65, 101588. [Google Scholar] [CrossRef] - Sun, W.; Zhang, J. Carbon Price Prediction Based on Ensemble Empirical Mode Decomposition and Extreme Learning Machine Optimized by Improved Bat Algorithm Considering Energy Price Factors. Energies
**2020**, 13, 3471. [Google Scholar] [CrossRef] - Bouri, E.; Dutta, A.; Saeed, T. Forecasting ethanol price volatility under structural breaks. Biofuels Bioprod. Biorefining
**2021**, 15, 250–256. [Google Scholar] [CrossRef] - Pokrivčák, J.; Rajčaniová, M. Crude oil price variability and its impact on ethanol prices. Agric. Econ.
**2011**, 57, 394–403. [Google Scholar] [CrossRef][Green Version] - Bastianin, A.; Galeotti, M.; Manera, M. Ethanol and field crops: Is there a price connection? Food Policy
**2016**, 63, 53–61. [Google Scholar] [CrossRef] - Bildirici, M.; Guler Bayazit, N.; Ucan, Y. Analyzing Crude Oil Prices under the Impact of COVID-19 by Using LSTARGARCHLSTM. Energies
**2020**, 13, 2980. [Google Scholar] [CrossRef] - Ding, S.; Zhang, Y. Cross market predictions for commodity prices. Econ. Model.
**2020**, 91, 455–462. [Google Scholar] [CrossRef] - Kulkarni, S.; Haidar, I. Forecasting model for crude oil price using artificial neural networks and commodity futures prices. arXiv
**2009**, arXiv:0906.4838. [Google Scholar] - Liu, Y.; Yang, C.; Huang, K.; Gui, W. Non-ferrous metals price forecasting based on variational mode decomposition and LSTM network. Knowl.-Based Syst.
**2020**, 188, 105006. [Google Scholar] [CrossRef] - Hu, Y.; Ni, J.; Wen, L. A hybrid deep learning approach by integrating LSTM-ANN networks with GARCH model for copper price volatility prediction. Phys. A Stat. Mech. Its Appl.
**2020**, 557, 124907. [Google Scholar] [CrossRef] - Zhou, B.; Zhao, S.; Chen, L.; Li, S.; Wu, Z.; Pan, G. Forecasting Price Trend of Bulk Commodities Leveraging Cross-Domain Open Data Fusion. ACM Trans. Intell. Syst. Technol.
**2020**, 11, 1–26. [Google Scholar] [CrossRef][Green Version] - Ouyang, H.; Wei, X.; Wu, Q. Agricultural commodity futures prices prediction via long- and short-term time series network. J. Appl. Econ.
**2019**, 22, 468–483. [Google Scholar] [CrossRef] - CEPEA—Center for Advanced Studies on Applied Economics. Available online: https://www.cepea.esalq.usp.br/en/cepea-1.aspx (accessed on 13 January 2021).
- Ariyawansha, T.; Abeyrathna, D.; Kulasekara, B.; Pottawela, D.; Kodithuwakku, D.; Ariyawansha, S.; Sewwandi, N.; Bandara, W.; Ahamed, T.; Noguchi, R. A novel approach to minimize energy requirements and maximize biomass utilization of the sugarcane harvesting system in Sri Lanka. Energies
**2020**, 13, 1497. [Google Scholar] [CrossRef][Green Version] - Franken, J.R.; Parcell, J.L. Cash Ethanol Cross-Hedging Opportunities. J. Agric. Appl. Econ.
**2003**, 35, 510–516. [Google Scholar] [CrossRef][Green Version] - Uhrig, R.E. Introduction to artificial neural networks. In Proceedings of the IECON’95-21st Annual Conference on IEEE Industrial Electronics, Orlando, FL, USA, 6–10 November 1995; Volume 1, pp. 33–37. [Google Scholar]
- Nakisa, B.; Rastgoo, M.N.; Rakotonirainy, A.; Maire, F.; Chandran, V. Long Short Term Memory Hyperparameter Optimization for a Neural Network Based Emotion Recognition Framework. IEEE Access
**2018**, 6, 49325–49338. [Google Scholar] [CrossRef] - Breuel, T.M. Benchmarking of LSTM Networks. arXiv
**2015**, arXiv:1508.02774. [Google Scholar] - Hochreiter, S.; Schmidhuber, J. Long Short-Term Memory. Neural Comput.
**1997**, 9, 1735–1780. [Google Scholar] [CrossRef] - Gers, F.A.; Schmidhuber, J.; Cummins, F. Learning to Forget: Continual Prediction with LSTM. Neural Comput.
**2000**, 12, 2451–2471. [Google Scholar] [CrossRef] - Yu, Y.; Si, X.; Hu, C.; Zhang, J. A Review of Recurrent Neural Networks: LSTM Cells and Network Architectures. Neural Comput.
**2019**, 31, 1235–1270. [Google Scholar] [CrossRef] - Greff, K.; Srivastava, R.K.; Koutník, J.; Steunebrink, B.R.; Schmidhuber, J. LSTM: A Search Space Odyssey. IEEE Trans. Neural Netw. Learn. Syst.
**2017**, 28, 2222–2232. [Google Scholar] [CrossRef] [PubMed][Green Version] - Graves, A.; Fernández, S.; Schmidhuber, J. Bidirectional LSTM Networks for Improved Phoneme Classification and Recognition. In Artificial Neural Networks: Formal Models and Their Applications—ICANN 2005; Duch, W., Kacprzyk, J., Oja, E., Zadrożny, S., Eds.; Springer: Berlin/Heidelberg, Germany, 2005; pp. 799–804. [Google Scholar]
- Habibi, M.; Weber, L.; Neves, M.; Wiegandt, D.L.; Leser, U. Deep learning with word embeddings improves biomedical named entity recognition. Bioinformatics
**2017**, 33, i37–i48. [Google Scholar] [CrossRef] [PubMed] - Zhou, C.; Sun, C.; Liu, Z.; Lau, F. A C-LSTM neural network for text classification. arXiv
**2015**, arXiv:1511.08630. [Google Scholar] - Zhou, P.; Qi, Z.; Zheng, S.; Xu, J.; Bao, H.; Xu, B. Text classification improved by integrating bidirectional LSTM with two-dimensional max pooling. arXiv
**2016**, arXiv:1611.06639. [Google Scholar] - Liu, G.; Guo, J. Bidirectional LSTM with attention mechanism and convolutional layer for text classification. Neurocomputing
**2019**, 337, 325–338. [Google Scholar] [CrossRef] - Sachan, D.S.; Zaheer, M.; Salakhutdinov, R. Revisiting lstm networks for semi-supervised text classification via mixed objective function. In Proceedings of the AAAI Conference on Artificial Intelligence, Honolulu, HI, USA, 27 January–1 February 2019; Volume 33, pp. 6940–6948. [Google Scholar]
- Bao, W.; Yue, J.; Rao, Y. A deep learning framework for financial time series using stacked autoencoders and long-short term memory. PLoS ONE
**2017**, 12, e0180944. [Google Scholar] [CrossRef][Green Version] - Siami-Namini, S.; Tavakoli, N.; Namin, A.S. A comparison of ARIMA and LSTM in forecasting time series. In Proceedings of the 2018 17th IEEE International Conference on Machine Learning and Applications (ICMLA), Orlando, FL, USA, 17–20 December 2018; pp. 1394–1401. [Google Scholar]
- Moghar, A.; Hamiche, M. Stock market prediction using LSTM recurrent neural network. Procedia Comput. Sci.
**2020**, 170, 1168–1173. [Google Scholar] [CrossRef] - Tong, G.; Yin, Z. Adaptive Trading System of Assets for International Cooperation in Agricultural Finance Based on Neural Network. Comput. Econ.
**2021**, 1–20. [Google Scholar] [CrossRef] - Karim, F.; Majumdar, S.; Darabi, H.; Chen, S. LSTM Fully Convolutional Networks for Time Series Classification. IEEE Access
**2018**, 6, 1662–1669. [Google Scholar] [CrossRef] - Mahasseni, B.; Lam, M.; Todorovic, S. Unsupervised video summarization with adversarial lstm networks. In Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, Honolulu, HI, USA, 21–26 July 2017; pp. 202–211. [Google Scholar]
- Sønderby, S.K.; Sønderby, C.K.; Nielsen, H.; Winther, O. Convolutional LSTM networks for subcellular localization of proteins. In International Conference on Algorithms for Computational Biology; Springer: Cham, Switzerland, 2015; pp. 68–80. [Google Scholar]
- Trinh, H.D.; Giupponi, L.; Dini, P. Mobile traffic prediction from raw data using LSTM networks. In Proceedings of the 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Bologna, Italy, 9–12 September 2018; pp. 1827–1832. [Google Scholar]
- Ycart, A.; Benetos, E. A Study on LSTM Networks for Polyphonic Music Sequence Modelling. In Proceedings of the International Society for Music Information Retrieval Conference (ISMIR), Suzhou, China, 23–28 October 2017. [Google Scholar]
- Srivastava, N.; Hinton, G.; Krizhevsky, A.; Sutskever, I.; Salakhutdinov, R. Dropout: A simple way to prevent neural networks from overfitting. J. Mach. Learn. Res.
**2014**, 15, 1929–1958. [Google Scholar] - Gers, F.A.; Schmidhuber, E. LSTM recurrent networks learn simple context-free and context-sensitive languages. IEEE Trans. Neural Netw.
**2001**, 12, 1333–1340. [Google Scholar] [CrossRef][Green Version] - Herrera, G.P.; Constantino, M.; Tabak, B.M.; Pistori, H.; Su, J.J.; Naranpanawa, A. Data on forecasting energy prices using machine learning. Data Brief
**2019**, 25, 104122. [Google Scholar] [CrossRef] [PubMed] - Carrasco, M.; López, J.; Maldonado, S. Epsilon-nonparallel support vector regression. Appl. Intell.
**2019**, 49, 4223–4236. [Google Scholar] [CrossRef] - Wang, X.; Zhou, T.; Wang, X.; Fang, Y. Harshness-aware sentiment mining framework for product review. Expert Syst. Appl.
**2022**, 187, 115887. [Google Scholar] [CrossRef] - Zhang, P.; Yin, Z.Y.; Zheng, Y.; Gao, F.P. A LSTM surrogate modelling approach for caisson foundations. Ocean Eng.
**2020**, 204, 107263. [Google Scholar] [CrossRef]

**Figure 2.**Architecture of LSTM with a forget gate. Reproduced from [34].

Forecast Horizon (Days) | Feature 1 | Feature 2 | Feature 3 | Feature 4 | Feature 5 | Feature 6 |
---|---|---|---|---|---|---|

63 | C${}_{t}$ | C${}_{t-63}$ | C${}_{t-126}$ | C${}_{t-189}$ | C${}_{t-252}$ | C${}_{t-315}$ |

126 | C${}_{t}$ | C${}_{t-126}$ | C${}_{t-252}$ | C${}_{t-378}$ | C${}_{t-504}$ | C${}_{t-630}$ |

252 | C${}_{t}$ | C${}_{t-252}$ | C${}_{t-504}$ | C${}_{t-756}$ | C${}_{t-1008}$ | C${}_{t-1260}$ |

63 Days Ahead | 126 Days Ahead | 252 Days Ahead | ||||
---|---|---|---|---|---|---|

Model | MAPE | RMSE | MAPE | RMSE | MAPE | RMSE |

LSTM | 17.23 | 78.53 | 19.91 | 83.38 | 26.15 | 98.69 |

RF | 21.49 | 94.48 | 22.28 | 95.78 | 32.12 | 127.26 |

SVML | 17.24 | 86.12 | 22.58 | 97.55 | 26.58 | 98.58 |

SVMR | 20.65 | 92.62 | 23.32 | 98.00 | 33.72 | 120.22 |

Model–Trend | Precision | Recall | Support | Accuracy | |
---|---|---|---|---|---|

LSTM–Downtrend | 0.59 | 0.88 | 173 | 72% | |

LSTM–Uptrend | 0.90 | 0.63 | 291 | ||

RF–Downtrend | 0.80 | 0.65 | 173 | 81% | |

RF–Uptrend | 0.81 | 0.90 | 291 | ||

SVML–Downtrend | 0.68 | 0.60 | 173 | 74% | |

SVML–Uptrend | 0.78 | 0.86 | 291 | ||

SVMR–Downtrend | 0.74 | 0.84 | 173 | 83% | |

SVMR–Uptrend | 0.90 | 0.82 | 291 |

Model–Trend | Precision | Recall | Support | Accuracy | |
---|---|---|---|---|---|

LSTM–Downtrend | 0.70 | 0.93 | 201 | 74% | |

LSTM–Uptrend | 0.86 | 0.52 | 187 | ||

RF–Downtrend | 0.95 | 0.71 | 201 | 83% | |

RF–Uptrend | 0.76 | 0.96 | 187 | ||

SVML–Downtrend | 0.84 | 0.78 | 201 | 81% | |

SVML–Uptrend | 0.78 | 0.83 | 187 | ||

SVMR–Downtrend | 0.83 | 0.84 | 201 | 83% | |

SVMR–Uptrend | 0.83 | 0.81 | 187 |

Model–Trend | Precision | Recall | Support | Accuracy | |
---|---|---|---|---|---|

LSTM–Downtrend | 0.88 | 0.88 | 200 | 80% | |

LSTM–Uptrend | 0.35 | 0.35 | 37 | ||

RF–Downtrend | 0.87 | 0.40 | 200 | 44% | |

RF–Uptrend | 0.17 | 0.68 | 37 | ||

SVML–Downtrend | 0.94 | 0.89 | 200 | 86% | |

SVML–Uptrend | 0.53 | 0.70 | 37 | ||

SVMR–Downtrend | 0.97 | 0.50 | 200 | 57% | |

SVMR–Uptrend | 0.25 | 0.92 | 37 |

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**MDPI and ACS Style**

Santos, G.C.; Barboza, F.; Veiga, A.C.P.; Silva, M.F.
Forecasting Brazilian Ethanol Spot Prices Using LSTM. *Energies* **2021**, *14*, 7987.
https://doi.org/10.3390/en14237987

**AMA Style**

Santos GC, Barboza F, Veiga ACP, Silva MF.
Forecasting Brazilian Ethanol Spot Prices Using LSTM. *Energies*. 2021; 14(23):7987.
https://doi.org/10.3390/en14237987

**Chicago/Turabian Style**

Santos, Gustavo Carvalho, Flavio Barboza, Antônio Cláudio Paschoarelli Veiga, and Mateus Ferreira Silva.
2021. "Forecasting Brazilian Ethanol Spot Prices Using LSTM" *Energies* 14, no. 23: 7987.
https://doi.org/10.3390/en14237987