Three Ha Tinh factories are taking power from up to 22 MWp of roof solar and a 45 MWh battery - the cost line is nearly 3.5 billion dong a year, and the tariff is blank
VietNamNet reported on 28 October 2026 that VinEnergo has switched on rooftop solar and a battery at the Vung Ang economic zone in Ha Tinh. The solar line is up to 22 MWp. The battery is 45 MWh. The article names the VinFast plant's owner, the VinES battery plant's owner, and a V-G battery joint venture as the customers. It calls this VinEnergo's first project under a direct power purchase mechanism. An estimate on the page is about 39 million kWh in the first year and nearly 3.5 billion dong of cost a year. No dong per kilowatt-hour and no contract length are printed. The battery's megawatts are not printed.
Three factories in one industrial zone are taking electricity from rooftop solar and a battery. The tariff is not on the page. A yearly cost figure is.
On 28 October 2026 VietNamNet reported that VinEnergo has put a rooftop solar system and a battery into operation at the Vung Ang Economic Zone in Ha Tinh. The timestamp on the article is 17:45 (GMT+07:00).
The size line. Solar up to 22 MWp. Battery 45 MWh. The article does not print the battery's power in megawatts. Hours are energy divided by power. Without the power, a duration is not a published figure. Dividing 45 MWh by 22 MWp and calling the result the battery's length would mix the solar array's size with the battery's energy. The article does not do that division.
The buyer line. The article calls this VinEnergo's first project under a direct power purchase mechanism. A direct power purchase is a contract to buy electricity from a named plant. The customers named are Công ty Cổ phần Sản xuất, Đầu tư và Phát triển Tương Lai, described as the owner and operator of the VinFast car and motorcycle factory in Ha Tinh, and Công ty Cổ phần Giải pháp Năng lượng VinES Hà Tĩnh, described as the owner of the VinES battery factory in Ha Tinh. The rooftop system also supplies the V-G battery joint-venture factory in the same zone. The article does not print a dong-per-kilowatt-hour price. It does not print a contract length. It does not say the factories own the panels.
The estimate line. The article says that, on an estimate, the system is expected to produce about 39 million kWh in the first year, and that this cuts more than 25,000 tonnes of CO2, written as equal to the absorption of more than 1.13 million trees a year. A further line puts the cost difference at nearly 3.5 billion dong a year. The article does not print the method. It does not print an exchange rate into another currency. 39 million kilowatt-hours divided by 22 MWp is 1,773 hours to the nearest hour, by our arithmetic, using the top of the "up to 22 MWp" line. The article does not print those hours.
A figure that is easy to paste onto the wrong line. The same article says VinEnergo is supplying batteries for projects of Hanoi Power Corporation and Northern Power Corporation at a total of more than 1.1 GWh. That is a different set of projects. It is not the 45 MWh at Vung Ang. The article also prints a renewable portfolio of up to 10 GW, and a target of up to 100 GW within three years. Those are company portfolio lines. They are not the size of this roof.
The next stage, on the same article. Supply to the three factories is described as a first stage. A later model is described as renewable energy with a very large battery, aimed at distribution and retail of electricity in the zone. No megawatt-hour figure is printed for that later battery.
The fill. The article says the system supplies the factories. It does not print a wholesale price for charging the battery from the grid, and it does not print a comparison with a gas plant. A battery holds only what solar or the grid puts in. The 3.5 billion dong line is an estimate of cost. It is not a tariff. A workplace that owns the panels on its own roof is a different contract from a direct purchase of someone else's output. An earlier note covered a near-site industrial contract with the price left blank. This one prints a battery energy size and a cost estimate, and still leaves the tariff blank.
Analogy: three plants are buying power from a roof that has a tank beside it. The tank's size is on the page. The price on the contract is not.
Good: A public date, three named industrial customers, a solar size, a battery energy size, a direct-purchase label, and an estimate kept separate from a tariff.
Bad: No dong per kilowatt-hour. No contract length. No battery megawatts, so no published duration. The 39 million kWh line, the CO2 line, the tree line and the 3.5 billion dong line are estimates, and the method is not printed. "Up to 22 MWp" is not a single guaranteed size.
Ugly: Treating more than 1.1 GWh as this site. Treating 10 GW or 100 GW as this roof. Dividing 45 MWh by 22 MWp and calling that the battery's hours. Dividing nearly 3.5 billion dong by 39 million kWh and calling the result a tariff. Reading the tree line as trees planted. Pasting the cost estimate onto a workplace that owns its own roof.
Soft next step: if a quote borrows the 3.5 billion dong line, the tariff and the term are not on this page, and the battery's hours are not either.
Source: VietNamNet, 28 Oct 2026 - VinEnergo switches on rooftop solar and a battery in Ha Tinh. Primary for the 28 October 2026 date and the 17:45 (GMT+07:00) timestamp, VinEnergo putting a rooftop solar system and a battery into operation at the Vung Ang Economic Zone in Ha Tinh, solar up to 22 MWp and a 45 MWh battery, the first VinEnergo project under a direct power purchase mechanism, customers Công ty Cổ phần Sản xuất, Đầu tư và Phát triển Tương Lai as owner and operator of the VinFast car and motorcycle factory in Ha Tinh and Công ty Cổ phần Giải pháp Năng lượng VinES Hà Tĩnh as owner of the VinES battery factory, supply also to the V-G battery joint-venture factory in the same zone, an estimate of about 39 million kWh in the first year, a cut of more than 25,000 tonnes of CO2 written as equal to the absorption of more than 1.13 million trees a year, nearly 3.5 billion dong of cost a year, batteries for Hanoi Power Corporation and Northern Power Corporation projects at more than 1.1 GWh in total, a renewable portfolio of up to 10 GW, and a target of up to 100 GW within three years. The article does not print a tariff, a contract length, the battery's megawatts, an exchange rate, the method behind the estimates, or a megawatt-hour size for a later battery. 39 million kWh divided by 22 MWp equals 1,773 hours to the nearest hour, using the top of the "up to 22 MWp" line, is our arithmetic. The article does not print that figure.