The following tables show our energy balance and the sufficiency of our self-supply scheme, offset by the surplus delivered to the National Electricity System and purchases from CFE. Clean energy generation covered 40.6% of our consumption—48.3% starting in April—the equivalent to the electricity consumed by 738,834 homes in Mexico in a year. With this we avoided the emission of 679,491 tCO₂e, almost double the figure than the previous year.

POWER GENERATION BY SOURCE
%

Source		Description	2020	2019
	Termoeléctrica Peñoles (TEP)	Located in Tamuín, San Luis Potosí, with installed capacity of 230 MW. It is operated by an independent company, and electricity is supplied under a power purchase agreement expiring in 2027.	57.8	68.0
	Eólica de Coahuila (EDC)	Located in General Cepeda, Coahuila, with installed capacity of 199.5 MW. The electricity is supplied under a power purchase agreement expiring in 2042.	20.5	23.7
	Eólica Mesa La Paz (MLP)	Located in Llera de Canales, Tamaulipas, with a capacity of 306 MW; operated by an independent company. Supply is committed under a power purchase contract expiring in 2045.	14.9	-
	Fuerza Eólica del Istmo (FEI)	Located in El Espinal, Oaxaca, operated by Peñoles; installed capacity of 80 MW.	6.1	6.4
	Cogeneration from Met-mex	Turbo-generator with 7 MW unit capacity that utilizes steam from the roasting area of the zinc plant.	0.7	1.9
Supply from proprietary sources in 2020 (3,466 GWh/year)			100.0	100.0
Energy generation in relation to consumption in 2020 (3,311 GWh/year)			104.7	90.1

Of the power generated by Grupo Peñoles' sources, 83.4% was assigned to Peñoles’ operations and 2.9% to other companies of Grupo BAL. The share for each source in Grupo Peñoles' consumption (without BAL) is shown in the following table:

In 2020, Peñoles’ total electricity consumption was 3,311 GWh (equivalent to an annual average demand of 378.0 MW), 2.7% lower than the previous year, due to the public health emergency and suspension of activities at three of our mining units. Additionally, the Peñoles’ energy division supplied 99.8 GWh to companies of Grupo BAL, for a total consumption of 3,411 GWh.

The average unit cost of the electricity consumed was US¢ 6.86/kWh, 6.7% higher than the previous year. This increase was due primarily to the sharp rise in transmission rates charged by CFE to legacy self-supply centrals—500% for renewables and 90% for thermoelectric plants—the constitutionality of which is under debate. There was also an increase in our consumption of energy purchased from the CFE, with a unit cost 14% higher than the energy supplied by our own plants.

New regulations for the power sector that took effect in 2018 require major users and suppliers of electricity to acquire Clean Energy Certificates (CELs). To cover the obligations accrued in 2019, we acquired 107,364 CELs in 2020, 16,000 of which were purchased from other companies and the rest were supplied by generation from the Mesa La Paz wind farm.

As we discussed in last year’s Annual Report, in 2016 the Energy Regulation Commission issued a new technical regulation called the Network Code, intended to guarantee the stability, reliability and security of the National Electricity System. Peñoles made the necessary adjustments to its electric installations to comply with the Code, particularly as regards energy quality indicators like power factor and harmonic current control. Furthermore, all of our high-voltage facilities completed their projects, in compliance with the technical and legal requirements of the Code.

In 2020, Fuentes de Energía Peñoles (FEPSA) began operating as a supplier of qualified services in the wholesale electricity market. FEPSA signed a power supply contract with the Mesa La Paz wind farm, and also represents the group’s consumers before the National Energy Control Center (CENACE).

Although 2020 presented significant challenges to our progress toward energy self-supply from renewable sources, we remain firm in our goal of increasing the share of clean technologies within the company’s energy portfolio. The execution will depend upon the national energy policy. In the meantime, we will continue to explore potential wind and solar farm projects.

With regard to our use of other fuels, we reduced our consumption of diesel by 13.2% during the year, and our natural gas consumption by 4.9%. Only the use of liquefied natural gas was increased to replace the use of diesel in heavy duty truckloads in open-pit mines to reduce greenhouse gas emissions. This project, together with the monitoring of emerging technologies such as the electrification of our mobile equipment, storage in batteries and production of hydrogen, opens possibilities for the long-awaited goal of being CO₂ emissions neutral.