Romania’s small hydropower plants: 370 plants on rivers, how much power they make and what they received through electricity bills

#How much electricity small hydro makes

At the end of 2025, 155 small hydro plants belonging to 82 producers were accredited for green certificates, with 194 MW. Small hydro with green certificates, including plants whose accreditation expired during the year, produced 466 GWh in 2025: 0.85% of Romania’s gross final electricity consumption (55,132 GWh). These reports do not give output for the other small plants in the register, including nearly all of Hidroelectrica’s.

In the same year Romania’s 295,476 prosumers, people, businesses and public bodies that make their own electricity, nearly all with solar panels, sent 1,770 GWh into the grid. That is only the electricity they did not use themselves. Homes alone (households) sent 1,080 GWh, 2.3 times what the subsidised small hydro plants made. The comparison is with subsidised small hydro, the only small hydro whose output the regulator publishes. Prosumers get no green certificates (the scheme closed to new plants at the end of 2016), but they have their own support: power they send to the grid is offset against power they take from it.

#What they received from green certificates

A green certificate is a bonus a producer receives for renewable electricity, on top of the price of the power. Electricity suppliers must buy certificates and bill the cost separately: in 2025, on average 73.1 lei per MWh, for all technologies. About 7.8 TWh of large consumers’ demand was exempt, so everyone else pays more.

The regulator’s annual reports show, by technology, how much producers earned from selling certificates. Small hydro received 2,273 million lei in 2018–2025, 10.5% of all the money paid for green certificates in those eight years. The sum starts in 2018; the scheme has paid small hydro since 2005, so the full total is higher.

In 2025 small hydro received 191 million lei from selling certificates, including some deferred from earlier years, and 261 million from selling electricity. The certificates issued for 2025 output (1,116,540, at about 146 lei each) are worth about 163 million lei, close to 350 lei per MWh on top of the price of the power.

What the regulator estimated about returns

Each year the regulator checks whether producers earn more than the European Commission approved when it cleared the scheme. In its report for 2025, the internal rate of return the regulator estimates for small hydro over the scheme’s life, in a base scenario, averages 6.6%, below the 7.4% threshold the Commission set in 2015. For plants accredited in 2015 and 2016, though, the estimate is 8.2% and 9.1%, above the threshold. The regulator concludes there is no overall risk of overcompensation. It proposes no measure: the rule only allows fewer certificates for new producers, and the scheme has admitted none since 2017 (overcompensation report for 2025).

#The source of the Argeș: 12 plants on the Capra and the Buda

The Argeș is born from two rivers of the Făgăraș Mountains, the Buda and the Capra, which meet above Lake Vidraru (Wikipedia). The regulator’s register lists 12 small hydro plants named after them in the commune of Arefu, 7 after the Capra and 5 after the Buda, with 15.2 MW. All were licensed in 2013 and all were accredited for green certificates at the end of 2025. Ten belong to Imob Expert Consulting, two to Mobil Den Steel.

In Arefu both rivers, as mapped on OpenStreetMap, run through the Natura 2000 site Munții Făgăraș and the Golul alpin Moldoveanu – Capra reserve. In 2015 the European Commission opened case INFR(2015)4036 over small hydro plants permitted on alpine rivers in three Natura 2000 sites. In November 2023 it sent Romania an additional letter of formal notice, because the permits had not been changed and the deterioration of one water body had not been remedied. The Commission writes that the river basin management plan shows the water body “Argeș from source to Lake Vidraru and tributaries” has deteriorated, and that some small plants were permitted without the assessment the Habitats Directive requires (Commission release). The release does not name the plants.

A case that reached court: the plant on the Taia river near Petrila. In a ruling reported in January 2018, the Hunedoara County Court found the project partly inside the Natura 2000 site Grădiștea Muncelului – Cioclovina and the Cheile Taia reserve; the ruling was not final (Adevărul, January 2018). MHC Taia is in the register, with 3.6 MW, and was accredited for green certificates at the end of 2025.

Show Arefu on the map

#How many small hydro plants are on rivers in protected areas

The most precise placing open data allows is the river: 110 plants carry the name of a river we found on OpenStreetMap in their commune. For 79 of them, the river runs through a Natura 2000 site within that commune; for 11, through a national park as well (Munții Rodnei, Călimani, Cozia, Retezat, Buila - Vânturarița).

A river crossing a site does not mean the water intake or the plant is inside it: they may lie upstream or downstream. When you pick a plant on the map you see its river in the commune and the protected areas it crosses.

Another 27 plants we found on OpenStreetMap itself, under their own names; 6 stand inside a protected area. For 204 we know only the village in the register; 28 of those villages lie in protected areas.

#How this was done, and what we do not know

• The plants: ANRE’s table of installed capacity in generating units at 24 April 2023. Rows per generating unit were summed per plant; we kept plants of up to 10 MW, the green-certificate threshold.
• Green certificates: the list of accredited plants at 31 December 2025, matched to the register by name; 150 of 155 were found.
• Money, output and consumption: ANRE’s annual monitoring reports 2018–2025 and its overcompensation report for 2025. Prosumers: ANRE report for 2025.
• Placing on the map: the commune from the SIRUTA register and UAT outlines (geo-spatial.org); rivers, villages and mapped plants from OpenStreetMap. A river is matched only when its name appears in the plant’s name.
• Protected areas: Natura 2000 sites (European Environment Agency, 2024) and nationally designated areas (European database of nationally designated areas). Relief: Copernicus GLO-30.
• What is missing: the exact site of plants and water intakes, the length of river whose water goes into pipes, the flow left in the riverbed, and the output of plants without green certificates. None of these is published as open data.